$SIGI
Selective Insurance Group Inc Stock $sigi

$sigi Overview Financials Valuation SEC Filings Company Website

2024 Q1 Form 10-K Financial Statement

#000023055724000005 Filed on February 09, 2024

Income Statement

Concept	2024 Q1	2023 Q4	2023
Revenue	$1.165B	$1.111B	$4.232B
YoY Change	16.52%	16.61%	18.94%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin	$15.50M	$3.400M	$30.70M
YoY Change	28.08%	-49.06%	-21.81%
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$219.4M	$6.640M	$24.70M
YoY Change	15.64%	-16.85%	0.41%
% of Gross Profit
Operating Expenses	$1.055B	$946.5M	$3.745B
YoY Change	20.21%	13.06%	15.26%
Operating Profit
YoY Change
Interest Expense	-$7.873M	-$7.200M	-$28.80M
YoY Change	9.35%	-5.06%	-52.77%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$102.6M	$157.0M	$458.4M
YoY Change	-10.62%	45.7%	63.61%
Income Tax	$20.05M	$32.10M	$93.20M
% Of Pretax Income	19.55%	20.45%	20.33%
Net Earnings	$82.52M	$122.5M	$356.0M
YoY Change	-10.86%	45.47%	58.3%
Net Earnings / Revenue	7.08%	11.03%	8.41%
Basic Earnings Per Share	$1.32		$5.87
Diluted Earnings Per Share	$1.31	$2.01	$5.84
COMMON SHARES
Basic Shares Outstanding	60.64M shares	60.59M shares	60.63M shares
Diluted Shares Outstanding	61.21M shares		60.97M shares

Balance Sheet

Concept	2024 Q1	2023 Q4	2023
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$11.84M	$13.27M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$82.70M	$83.30M	$83.30M
YoY Change	-0.8%	-1.19%	-34.26%
Goodwill	$7.849M	$7.800M
YoY Change	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments	$8.746B	$8.694B	$8.694B
YoY Change	8.92%	10.92%	10.92%
Other Assets	$156.4M	$153.3M	$153.3M
YoY Change	-19.19%	-22.54%	-22.54%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$12.06B	$11.80B	$11.80B
YoY Change	9.45%	9.26%	9.26%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$97.92M	$122.0M	$122.0M
YoY Change	10.27%	-23.6%	-23.6%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$124.4M	$128.3M	$128.3M
YoY Change	14.07%	-19.66%	-19.66%
LONG-TERM LIABILITIES
Long-Term Debt	$503.3M	$503.9M	$503.9M
YoY Change	-0.18%	-0.15%	-0.15%
Other Long-Term Liabilities	$479.1M	$548.3M	$548.3M
YoY Change	-11.34%	15.99%	15.99%
Total Long-Term Liabilities	$982.4M	$1.052B	$1.052B
YoY Change	-5.95%	7.65%	7.65%
TOTAL LIABILITIES
Total Short-Term Liabilities	$124.4M	$128.3M	$128.3M
Total Long-Term Liabilities	$982.4M	$1.052B	$1.052B
Total Liabilities	$9.050B	$8.848B	$8.848B
YoY Change	8.44%	6.93%	6.93%
SHAREHOLDERS EQUITY
Retained Earnings	$3.088B	$3.029B
YoY Change	9.45%	10.17%
Common Stock	$745.2M	$733.2M
YoY Change	4.54%	4.27%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$641.9M	$635.2M
YoY Change	1.13%	1.26%
Treasury Stock Shares
Shareholders Equity	$3.006B	$2.954B	$2.954B
YoY Change
Total Liabilities & Shareholders Equity	$12.06B	$11.80B	$11.80B
YoY Change	9.45%	9.26%	9.26%

Cashflow Statement

Concept	2024 Q1	2023 Q4	2023
OPERATING ACTIVITIES
Net Income	$82.52M	$122.5M	$356.0M
YoY Change	-10.86%	45.47%	58.3%
Depreciation, Depletion And Amortization	$219.4M	$6.640M	$24.70M
YoY Change	15.64%	-16.85%	0.41%
Cash From Operating Activities	$114.2M	$236.6M	$758.9M
YoY Change	-15.88%	-25.35%	-5.42%
INVESTING ACTIVITIES
Capital Expenditures	$6.199M	$7.831M	$22.63M
YoY Change	12.5%	83.78%	-13.02%
Acquisitions
YoY Change
Other Investing Activities	-$79.81M	-$208.4M	-$663.7M
YoY Change	-13.93%	-25.38%	-6.31%
Cash From Investing Activities	-$86.01M	-$216.4M	-$686.4M
YoY Change	-12.45%	-23.71%	-6.55%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-$29.63M	-20.39M	-$84.49M
YoY Change	9.43%	18.48%	-3.79%
NET CHANGE
Cash From Operating Activities	$114.2M	236.6M	$758.9M
Cash From Investing Activities	-$86.01M	-216.4M	-$686.4M
Cash From Financing Activities	-$29.63M	-20.39M	-$84.49M
Net Change In Cash	-$1.428M	-137.0K	-$11.94M
YoY Change	-113.66%	-100.85%	-39.88%
FREE CASH FLOW
Cash From Operating Activities	$114.2M	$236.6M	$758.9M
Capital Expenditures	$6.199M	$7.831M	$22.63M
Free Cash Flow	$108.0M	$228.8M	$736.3M
YoY Change	-17.08%	-26.84%	-5.17%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2023	us-gaap	Other Income OtherIncome	19402000	usd
CY2023	us-gaap	Revenues Revenues	4232106000	usd
CY2022	us-gaap	Revenues Revenues	3558062000	usd
CY2022	us-gaap	Incurred Claims Property Casualty And Liability IncurredClaimsPropertyCasualtyAndLiability	2111778000	usd
CY2021	us-gaap	Incurred Claims Property Casualty And Liability IncurredClaimsPropertyCasualtyAndLiability	1813984000	usd
CY2021	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	626469000	usd
CY2023	dei	Amendment Flag AmendmentFlag	false
CY2023	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2023
CY2023	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2023	dei	Entity Central Index Key EntityCentralIndexKey	0000230557
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherAssets
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherAssets
CY2023Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2022Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNet
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNet
CY2023Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#LongTermDebt
CY2022Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#LongTermDebt
CY2023	dei	Document Annual Report DocumentAnnualReport	true
CY2023	dei	Document Period End Date DocumentPeriodEndDate	2023-12-31
CY2023	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2023	dei	Document Transition Report DocumentTransitionReport	false
CY2023	dei	Entity File Number EntityFileNumber	001-33067
CY2023	dei	Entity Registrant Name EntityRegistrantName	SELECTIVE INSURANCE GROUP, INC.
CY2023	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	NJ
CY2023	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	22-2168890
CY2023	dei	Entity Address Address Line1 EntityAddressAddressLine1	40 Wantage Avenue
CY2023	dei	Entity Address City Or Town EntityAddressCityOrTown	Branchville
CY2023	dei	Entity Address State Or Province EntityAddressStateOrProvince	NJ
CY2023	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	07890
CY2023	dei	City Area Code CityAreaCode	(973)
CY2023	dei	Local Phone Number LocalPhoneNumber	948-3000
CY2023	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2023	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2023	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2023	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2023	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2023	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2023	dei	Entity Small Business EntitySmallBusiness	false
CY2023	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2023	dei	Document Fin Stmt Error Correction Flag DocumentFinStmtErrorCorrectionFlag	false
CY2023	dei	Entity Shell Company EntityShellCompany	false
CY2023Q2	dei	Entity Public Float EntityPublicFloat	5764421938	usd
CY2024Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	60641846	shares
CY2023	dei	Auditor Name AuditorName	KPMG LLP
CY2023	dei	Auditor Location AuditorLocation	New York, New York
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	21923000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	29837000	usd
CY2023Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	22700000	usd
CY2022Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	31157000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Amortized Cost After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss	22700000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Amortized Cost After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss	31157000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	28212000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	45721000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7880697000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7185754000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	7499197000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6612107000	usd
CY2023Q4	sigi	Commercial Mortgage Loan Fair Value CommercialMortgageLoanFairValue	178913000	usd
CY2022Q4	sigi	Commercial Mortgage Loan Fair Value CommercialMortgageLoanFairValue	139243000	usd
CY2023Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	188708000	usd
CY2022Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	149305000	usd
CY2023Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	291000	usd
CY2022Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	116000	usd
CY2023Q4	us-gaap	Mortgage Loans On Real Estate Commercial And Consumer Net MortgageLoansOnRealEstateCommercialAndConsumerNet	188417000	usd
CY2022Q4	us-gaap	Mortgage Loans On Real Estate Commercial And Consumer Net MortgageLoansOnRealEstateCommercialAndConsumerNet	149189000	usd
CY2023Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	183076000	usd
CY2022Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	167431000	usd
CY2023Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	187155000	usd
CY2022Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	162000000	usd
CY2023Q4	us-gaap	Other Short Term Investments OtherShortTermInvestments	309317000	usd
CY2022Q4	us-gaap	Other Short Term Investments OtherShortTermInvestments	440456000	usd
CY2023Q4	us-gaap	Alternative Investment AlternativeInvestment	395779000	usd
CY2022Q4	us-gaap	Alternative Investment AlternativeInvestment	371316000	usd
CY2023Q4	us-gaap	Other Investments OtherInvestments	91164000	usd
CY2022Q4	us-gaap	Other Investments OtherInvestments	71244000	usd
CY2023Q4	us-gaap	Investments Investments	8693729000	usd
CY2022Q4	us-gaap	Investments Investments	7837469000	usd
CY2023Q4	us-gaap	Cash Cash	180000	usd
CY2022Q4	us-gaap	Cash Cash	26000	usd
CY2023Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	13092000	usd
CY2022Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	25183000	usd
CY2023Q4	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	66339000	usd
CY2022Q4	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	59167000	usd
CY2023Q4	us-gaap	Premiums Receivable Gross PremiumsReceivableGross	1331979000	usd
CY2022Q4	us-gaap	Premiums Receivable Gross PremiumsReceivableGross	1101787000	usd
CY2023Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	18900000	usd
CY2022Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	16100000	usd
CY2023Q4	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	1313079000	usd
CY2022Q4	us-gaap	Premiums Receivable At Carrying Value PremiumsReceivableAtCarryingValue	1085687000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	658525000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	784410000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1700000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	656825000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	782810000	usd
CY2023Q4	us-gaap	Prepaid Reinsurance Premiums PrepaidReinsurancePremiums	203320000	usd
CY2022Q4	us-gaap	Prepaid Reinsurance Premiums PrepaidReinsurancePremiums	172371000	usd
CY2023Q4	us-gaap	Income Tax Receivable IncomeTaxReceivable	0	usd
CY2022Q4	us-gaap	Income Tax Receivable IncomeTaxReceivable	3545000	usd
CY2023Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	140237000	usd
CY2022Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	172733000	usd
CY2023Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	271409000	usd
CY2022Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	251209000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	83272000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	84306000	usd
CY2023Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	424864000	usd
CY2022Q4	us-gaap	Deferred Policy Acquisition Costs DeferredPolicyAcquisitionCosts	368624000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	7849000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	7849000	usd
CY2023Q4	us-gaap	Other Assets OtherAssets	199760000	usd
CY2022Q4	us-gaap	Other Assets OtherAssets	202491000	usd
CY2023Q4	us-gaap	Assets Assets	11802546000	usd
CY2022Q4	us-gaap	Assets Assets	10802261000	usd
CY2023Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	5336911000	usd
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense Property Casualty Liability LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability	5144821000	usd
CY2023Q4	us-gaap	Unearned Premiums UnearnedPremiums	2330656000	usd
CY2022Q4	us-gaap	Unearned Premiums UnearnedPremiums	1992781000	usd
CY2023Q4	us-gaap	Long Term Debt LongTermDebt	503946000	usd
CY2022Q4	us-gaap	Long Term Debt LongTermDebt	504676000	usd
CY2023Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	6251000	usd
CY2022Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	0	usd
CY2023Q4	us-gaap	Accrued Salaries Current And Noncurrent AccruedSalariesCurrentAndNoncurrent	122003000	usd
CY2022Q4	us-gaap	Accrued Salaries Current And Noncurrent AccruedSalariesCurrentAndNoncurrent	115185000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	548398000	usd
CY2022Q4	us-gaap	Other Liabilities OtherLiabilities	517234000	usd
CY2023Q4	us-gaap	Liabilities Liabilities	8848165000	usd
CY2022Q4	us-gaap	Liabilities Liabilities	8274697000	usd
CY2022Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0
CY2023Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0
CY2023Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2023Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25000
CY2022Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25000
CY2023Q4	us-gaap	Preferred Stock Value PreferredStockValue	200000000	usd
CY2022Q4	us-gaap	Preferred Stock Value PreferredStockValue	200000000	usd
CY2022Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	2
CY2023Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	2
CY2023Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	360000000	shares
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	360000000	shares
CY2023Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	105223307	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	104847111	shares
CY2023Q4	us-gaap	Common Stock Value CommonStockValue	210447000	usd
CY2022Q4	us-gaap	Common Stock Value CommonStockValue	209694000	usd
CY2023Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	522748000	usd
CY2022Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	493488000	usd
CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	3029396000	usd
CY2022Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	2749703000	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-373001000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-498042000	usd
CY2023Q4	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	44586870	shares
CY2022Q4	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	44508211	shares
CY2023Q4	us-gaap	Treasury Stock Value TreasuryStockValue	635209000	usd
CY2022Q4	us-gaap	Treasury Stock Value TreasuryStockValue	627279000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	2954381000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	2527564000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	11802546000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	10802261000	usd
CY2023	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3827606000	usd
CY2022	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3373380000	usd
CY2021	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3017253000	usd
CY2023	us-gaap	Net Investment Income NetInvestmentIncome	388650000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	288155000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	326589000	usd
CY2023	us-gaap	Gain Loss On Investments GainLossOnInvestments	-3552000	usd
CY2022	us-gaap	Gain Loss On Investments GainLossOnInvestments	-114808000	usd
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	17599000	usd
CY2022	us-gaap	Other Income OtherIncome	11335000	usd
CY2021	us-gaap	Other Income OtherIncome	17723000	usd
CY2021	us-gaap	Revenues Revenues	3379164000	usd
CY2023	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	30686000	usd
CY2023	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	3773694000	usd
CY2022	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	3277876000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	458412000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	280186000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	505310000	usd
CY2023	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	94022000	usd
CY2022	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	78308000	usd
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	87335000	usd
CY2023	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-848000	usd
CY2022	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-23008000	usd
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	14138000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93174000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	55300000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	101473000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	365238000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	224886000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	403837000	usd
CY2023	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9200000	usd
CY2022	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9200000	usd
CY2021	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9353000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	356038000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	215686000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	394484000	usd
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.87
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.57
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.55
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.84
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.54
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.50
CY2023	us-gaap	Net Income Loss NetIncomeLoss	365238000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	224886000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	403837000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	84407000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-527805000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-119598000	usd
CY2023	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	47585000	usd
CY2022	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	-148495000	usd
CY2021	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	-7159000	usd
CY2023	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Netof Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleNetofTax	0	usd
CY2022	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Netof Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleNetofTax	-3000	usd
CY2021	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Netof Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleNetofTax	9000	usd
CY2023	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	16162000	usd
CY2022	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	47438000	usd
CY2021	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	-3022000	usd
CY2023	sigi	Debt Securities Available For Sale Credit Loss Net DebtSecuritiesAvailableForSaleCreditLossNet	-10189000	usd
CY2022	sigi	Debt Securities Available For Sale Credit Loss Net DebtSecuritiesAvailableForSaleCreditLossNet	30944000	usd
CY2021	sigi	Debt Securities Available For Sale Credit Loss Net DebtSecuritiesAvailableForSaleCreditLossNet	5418000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	137965000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-597915000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-124370000	usd
CY2023	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-15315000	usd
CY2022	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-16543000	usd
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	17093000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-2391000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1317000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-2190000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	12924000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	15226000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-19283000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	125041000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-613141000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-105087000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	490279000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-388255000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	298750000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	2954381000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	2527564000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	2982885000	usd
CY2023	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	1150
CY2022	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	1150
CY2021	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	1169.17
CY2023	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.25
CY2022	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.14
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.03
CY2022Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2021Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2020Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2021Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	60338900	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	60184382	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	59905803	shares
CY2023	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	18608	shares
CY2022	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	22093	shares
CY2021	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	22986	shares
CY2023	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	357588	shares
CY2022	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	374102	shares
CY2021	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	395018	shares
CY2023	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	0	shares
CY2022	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	165159	shares
CY2021	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	52781	shares
CY2023	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	78659	shares
CY2022	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	76518	shares
CY2021	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	86644	shares
CY2023Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	60636437	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	60338900	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	60184382	shares
CY2023	us-gaap	Net Income Loss NetIncomeLoss	365238000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	224886000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	403837000	usd
CY2023	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	30040000	usd
CY2022	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	42336000	usd
CY2021	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	55109000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	18346000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	18428000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	15893000	usd
CY2023	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	17083000	usd
CY2022	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	12946000	usd
CY2021	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	69873000	usd
CY2023	sigi	Proceeds From Equity Investments In Excess Of Current Year Earnings ProceedsFromEquityInvestmentsInExcessOfCurrentYearEarnings	16052000	usd
CY2022	sigi	Proceeds From Equity Investments In Excess Of Current Year Earnings ProceedsFromEquityInvestmentsInExcessOfCurrentYearEarnings	43184000	usd
CY2021	sigi	Proceeds From Equity Investments In Excess Of Current Year Earnings ProceedsFromEquityInvestmentsInExcessOfCurrentYearEarnings	2910000	usd
CY2023	us-gaap	Gain Loss On Investments GainLossOnInvestments	-3552000	usd
CY2022	us-gaap	Gain Loss On Investments GainLossOnInvestments	-114808000	usd
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	17599000	usd
CY2023	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	6000	usd
CY2022	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-172000	usd
CY2021	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-50000	usd
CY2023	sigi	Increase Decrease In Reserves For Losses And Loss Expenses Net Of Reinsurance Recoverables IncreaseDecreaseInReservesForLossesAndLossExpensesNetOfReinsuranceRecoverables	318075000	usd
CY2022	sigi	Increase Decrease In Reserves For Losses And Loss Expenses Net Of Reinsurance Recoverables IncreaseDecreaseInReservesForLossesAndLossExpensesNetOfReinsuranceRecoverables	381176000	usd
CY2021	sigi	Increase Decrease In Reserves For Losses And Loss Expenses Net Of Reinsurance Recoverables IncreaseDecreaseInReservesForLossesAndLossExpensesNetOfReinsuranceRecoverables	307972000	usd
CY2023	sigi	Increase Decrease In Unearned Premiums Net Of Prepaid Reinsurance IncreaseDecreaseInUnearnedPremiumsNetOfPrepaidReinsurance	306926000	usd
CY2022	sigi	Increase Decrease In Unearned Premiums Net Of Prepaid Reinsurance IncreaseDecreaseInUnearnedPremiumsNetOfPrepaidReinsurance	200210000	usd
CY2021	sigi	Increase Decrease In Unearned Premiums Net Of Prepaid Reinsurance IncreaseDecreaseInUnearnedPremiumsNetOfPrepaidReinsurance	172460000	usd
CY2023	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	9082000	usd
CY2022	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-25932000	usd
CY2021	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-542000	usd
CY2023	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	227392000	usd
CY2022	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	140500000	usd
CY2021	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	109173000	usd
CY2023	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	56240000	usd
CY2022	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	41709000	usd
CY2021	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	38337000	usd
CY2023	us-gaap	Increase Decrease In Interest And Dividends Receivable IncreaseDecreaseInInterestAndDividendsReceivable	7172000	usd
CY2022	us-gaap	Increase Decrease In Interest And Dividends Receivable IncreaseDecreaseInInterestAndDividendsReceivable	10920000	usd
CY2021	us-gaap	Increase Decrease In Interest And Dividends Receivable IncreaseDecreaseInInterestAndDividendsReceivable	3243000	usd
CY2023	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	6430000	usd
CY2022	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	-3092000	usd
CY2021	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	7216000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	23195000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	37561000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	33379000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	16255000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	49869000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	78121000	usd
CY2023	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	758908000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	802409000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	771422000	usd
CY2023	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	0	usd
CY2022	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	6691000	usd
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	16250000	usd
CY2023	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2438851000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2648974000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2165555000	usd
CY2023	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	42114000	usd
CY2022	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	64008000	usd
CY2021	us-gaap	Payments To Acquire Mortgage Notes Receivable PaymentsToAcquireMortgageNotesReceivable	50204000	usd
CY2023	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	24166000	usd
CY2022	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	26675000	usd
CY2021	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	88640000	usd
CY2023	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	97597000	usd
CY2022	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	73408000	usd
CY2021	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	85044000	usd
CY2023	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	4479918000	usd
CY2022	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	4506500000	usd
CY2021	us-gaap	Payments To Acquire Short Term Investments PaymentsToAcquireShortTermInvestments	4345140000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1221918000	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1211739000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	502911000	usd
CY2023	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	2711000	usd
CY2022	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	10498000	usd
CY2021	us-gaap	Proceeds From Sale And Collection Of Mortgage Notes Receivable ProceedsFromSaleAndCollectionOfMortgageNotesReceivable	714000	usd
CY2023	us-gaap	Proceeds From Sale Of Short Term Investments ProceedsFromSaleOfShortTermInvestments	4611342000	usd
CY2022	us-gaap	Proceeds From Sale Of Short Term Investments ProceedsFromSaleOfShortTermInvestments	4513940000	usd
CY2021	us-gaap	Proceeds From Sale Of Short Term Investments ProceedsFromSaleOfShortTermInvestments	4306684000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8458000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	4351000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	4192000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	509220000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	669211000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1217555000	usd
CY2023	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	53344000	usd
CY2022	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	186144000	usd
CY2021	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	99235000	usd
CY2023	us-gaap	Proceeds From Sale Of Equity Method Investments ProceedsFromSaleOfEquityMethodInvestments	900000	usd
CY2022	us-gaap	Proceeds From Sale Of Equity Method Investments ProceedsFromSaleOfEquityMethodInvestments	3281000	usd
CY2021	us-gaap	Proceeds From Sale Of Equity Method Investments ProceedsFromSaleOfEquityMethodInvestments	5428000	usd
CY2023	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	11029000	usd
CY2022	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	18664000	usd
CY2023	us-gaap	Use Of Estimates UseOfEstimates	Use of Estimates<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of our Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported financial statement balances, as well as the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.</span></div>
CY2021	us-gaap	Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital ProceedsFromEquityMethodInvestmentDividendsOrDistributionsReturnOfCapital	17497000	usd
CY2023	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	22631000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	26019000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	22163000	usd
CY2023	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-686355000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-734447000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-618780000	usd
CY2023	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	9200000	usd
CY2022	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	9200000	usd
CY2021	us-gaap	Payments Of Dividends Preferred Stock And Preference Stock PaymentsOfDividendsPreferredStockAndPreferenceStock	9353000	usd
CY2023	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	73827000	usd
CY2022	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	66920000	usd
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	60136000	usd
CY2023	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	7930000	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	18344000	usd
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	9050000	usd
CY2023	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	9133000	usd
CY2022	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	9086000	usd
CY2021	us-gaap	Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions	7976000	usd
CY2023	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	usd
CY2022	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	0	usd
CY2021	us-gaap	Proceeds From Issuance Of Preferred Stock And Preference Stock ProceedsFromIssuanceOfPreferredStockAndPreferenceStock	479000	usd
CY2023	us-gaap	Proceeds From Debt Net Of Issuance Costs ProceedsFromDebtNetOfIssuanceCosts	20000000	usd
CY2021	us-gaap	Repayments Of Debt RepaymentsOfDebt	50000000	usd
CY2022	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2438000	usd
CY2021	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1768000	usd
CY2023	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-84490000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-87816000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-122810000	usd
CY2023	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-11937000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-19854000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	29832000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	25209000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	45063000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	15231000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	13272000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	25209000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	45063000	usd
CY2023	us-gaap	Nature Of Operations NatureOfOperations	Organization<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Selective Insurance Group, Inc., through its subsidiaries, (collectively referred to as “we,” “us,” or “our”) offers standard commercial, standard personal, and excess and surplus ("E&S") lines property and casualty insurance products. Selective Insurance Group, Inc. (referred to as the “Parent”) was incorporated in New Jersey in 1977 and its corporate headquarters is located in Branchville, New Jersey. The Parent’s common and preferred stock are publicly traded on the Nasdaq Global Select Market under the symbols “SIGI” and "SIGIP," respectively. We have provided a glossary of terms as Exhibit 99.1 to this Form 10-K, which defines certain industry-specific and other terms that are used in this Form 10-K.</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </span></div><div style="margin-bottom:10pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We classify our business into four reportable segments, which are as follows:</span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">Standard Commercial Lines – comprised of property and casualty insurance products and services provided in the standard marketplace to commercial enterprises, which are typically businesses, non-profit organizations, and local government agencies.</span></div><div style="padding-left:36pt"><span><br/></span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">Standard Personal Lines – comprised of property and casualty insurance products and services, including flood insurance coverage, provided primarily to individuals acquiring coverage in the standard marketplace.</span></div><div style="padding-left:36pt"><span><br/></span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">E&S Lines – comprised of property and casualty insurance products and services provided to customers who are unable to obtain coverage in the standard marketplace.</span></div><div style="padding-left:36pt"><span><br/></span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">Investments – invests the premiums collected by our insurance operations, as well as amounts generated through our capital management strategies, which may include the issuance of debt and equity securities.</span></div>
CY2023	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	4
CY2023	us-gaap	Depreciation Depreciation	24700000	usd
CY2022	us-gaap	Depreciation Depreciation	24600000	usd
CY2021	us-gaap	Depreciation Depreciation	24300000	usd
	sigi	Investment Yields Assumed In Premium Deficiency Assessment InvestmentYieldsAssumedInPremiumDeficiencyAssessment	0.048
	sigi	Investment Yields Assumed In Premium Deficiency Assessment InvestmentYieldsAssumedInPremiumDeficiencyAssessment	0.035
	sigi	Investment Yields Assumed In Premium Deficiency Assessment InvestmentYieldsAssumedInPremiumDeficiencyAssessment	0.043
CY2023	us-gaap	Interest Paid Net InterestPaidNet	28359000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	26639000	usd
CY2021	us-gaap	Interest Paid Net InterestPaidNet	28930000	usd
CY2023	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	79702000	usd
CY2022	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	75000000	usd
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	100000000	usd
CY2023	us-gaap	Operating Lease Payments OperatingLeasePayments	7409000	usd
CY2022	us-gaap	Operating Lease Payments OperatingLeasePayments	8148000	usd
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	7935000	usd
CY2023	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	66000	usd
CY2022	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	46000	usd
CY2021	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	35000	usd
CY2023	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2666000	usd
CY2022	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2438000	usd
CY2021	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1768000	usd
CY2023	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	50253000	usd
CY2022	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	usd
CY2021	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	usd
CY2023	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1584000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	707000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	6709000	usd
CY2023	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	5885000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	16649000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3272000	usd
CY2023	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	242000	usd
CY2022	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	70000	usd
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	472000	usd
CY2023Q4	us-gaap	Cash Cash	180000	usd
CY2022Q4	us-gaap	Cash Cash	26000	usd
CY2023Q4	us-gaap	Restricted Cash RestrictedCash	13092000	usd
CY2022Q4	us-gaap	Restricted Cash RestrictedCash	25183000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	13272000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	25209000	usd
CY2023Q4	sigi	Unrealized Gain Loss On Investment Securities UnrealizedGainLossOnInvestmentSecurities	-353253000	usd
CY2022Q4	sigi	Unrealized Gain Loss On Investment Securities UnrealizedGainLossOnInvestmentSecurities	-527891000	usd
CY2021Q4	sigi	Unrealized Gain Loss On Investment Securities UnrealizedGainLossOnInvestmentSecurities	228963000	usd
CY2023Q4	sigi	Deferred Income Tax Expense Benefit On Investment Securities In Other Comprehensive Income DeferredIncomeTaxExpenseBenefitOnInvestmentSecuritiesInOtherComprehensiveIncome	-74184000	usd
CY2022Q4	sigi	Deferred Income Tax Expense Benefit On Investment Securities In Other Comprehensive Income DeferredIncomeTaxExpenseBenefitOnInvestmentSecuritiesInOtherComprehensiveIncome	-110857000	usd
CY2021Q4	sigi	Deferred Income Tax Expense Benefit On Investment Securities In Other Comprehensive Income DeferredIncomeTaxExpenseBenefitOnInvestmentSecuritiesInOtherComprehensiveIncome	48082000	usd
CY2023Q4	sigi	Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax	-279069000	usd
CY2022Q4	sigi	Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax	-417034000	usd
CY2021Q4	sigi	Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax	180881000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	137965000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-597915000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-124370000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7880697000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	28212000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	50076000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	403364000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	7499197000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7185754000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	45721000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	9262000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	537188000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6612107000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	45721000	usd
CY2023	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not Previously Recorded DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded	4142000	usd
CY2023	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Purchased With Credit Deterioration Increase DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	0	usd
CY2023	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not To Sell Before Recovery Credit Loss Previously Recorded Expense Reversal DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal	-17040000	usd
CY2023	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Securities Sold DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold	-4340000	usd
CY2023	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Sell Before Recovery DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery	-271000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	28212000	usd
CY2021Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	9724000	usd
CY2022	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not Previously Recorded DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded	34561000	usd
CY2022	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Purchased With Credit Deterioration Increase DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	8318000	usd
CY2022	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Not To Sell Before Recovery Credit Loss Previously Recorded Expense Reversal DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal	4608000	usd
CY2022	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Securities Sold DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold	-7636000	usd
CY2022	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss Sell Before Recovery DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery	-3854000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	45721000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	511125000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	0	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	0	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	3450675000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	13624000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	13307000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	2817046000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	9076000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	8616000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	720351000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	0	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	0	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	7499197000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Amortized Cost After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss	22700000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	21923000	usd
CY2023	sigi	Schedule Of Other Investment Portfolio By Strategy And Remaining Commitment Amount Associated With Each Strategy Textblock ScheduleOfOtherInvestmentPortfolioByStrategyAndRemainingCommitmentAmountAssociatedWithEachStrategyTextblock	<div><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:99.853%"><tr><td style="width:1.0%"></td><td style="width:20.422%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.052%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.052%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.077%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.052%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.052%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.385%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.083%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="15" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31, 2023</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="15" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">December 31, 2022</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">($ in thousands)</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Carrying<br/>Value</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Remaining<br/>Commitment</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Maximum<br/>Exposure to Loss</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Carrying<br/>Value</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Remaining<br/>Commitment</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Maximum<br/>Exposure to Loss</span></td></tr><tr><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Alternative investments</span></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"> </span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Private equity</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">301,759</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">131,885</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">433,644</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">280,980 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">134,676 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">415,656 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Private credit</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">54,500</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">89,401</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">143,901</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">54,866 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">89,481 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">144,347 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Real assets</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">39,520</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">33,040</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">72,560</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">35,470 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">21,945 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">57,415 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt 2px 12.25pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total alternative investments</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">395,779</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">254,326</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">650,105</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">371,316 </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">246,102 </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">617,418 </span></td><td style="background-color:#cdffcc;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div>
CY2022Q4	sigi	Maximumexposuretocreditconcentrationriskofthe Companysstockholdersequityotherthancertain U.S.Governmentagencies MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies	0.10
CY2023Q4	sigi	Maximumexposuretocreditconcentrationriskofthe Companysstockholdersequityotherthancertain U.S.Governmentagencies MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies	0.10
CY2023	us-gaap	Net Investment Income NetInvestmentIncome	388650000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	288155000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	326589000	usd
CY2023	sigi	Debt And Equity Securities Realized Gains DebtAndEquitySecuritiesRealizedGains	5896000	usd
CY2022	sigi	Debt And Equity Securities Realized Gains DebtAndEquitySecuritiesRealizedGains	28419000	usd
CY2021	sigi	Debt And Equity Securities Realized Gains DebtAndEquitySecuritiesRealizedGains	15284000	usd
CY2023	sigi	Debt And Equity Securities Realized Losses DebtAndEquitySecuritiesRealizedLosses	30760000	usd
CY2022	sigi	Debt And Equity Securities Realized Losses DebtAndEquitySecuritiesRealizedLosses	60055000	usd
CY2021	sigi	Debt And Equity Securities Realized Losses DebtAndEquitySecuritiesRealizedLosses	8140000	usd
CY2023	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-24864000	usd
CY2022	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-31636000	usd
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	7144000	usd
CY2023	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	9510000	usd
CY2022	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-32127000	usd
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	17881000	usd
CY2023	sigi	Losses On Investment Securities For Which We Have The Intent To Sell LossesOnInvestmentSecuritiesForWhichWeHaveTheIntentToSell	921000	usd
CY2022	sigi	Losses On Investment Securities For Which We Have The Intent To Sell LossesOnInvestmentSecuritiesForWhichWeHaveTheIntentToSell	11823000	usd
CY2021	sigi	Losses On Investment Securities For Which We Have The Intent To Sell LossesOnInvestmentSecuritiesForWhichWeHaveTheIntentToSell	519000	usd
CY2023	us-gaap	Gain Loss On Investments GainLossOnInvestments	-3552000	usd
CY2022	us-gaap	Gain Loss On Investments GainLossOnInvestments	-114808000	usd
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	17599000	usd
CY2023	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	3593000	usd
CY2022	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	-10454000	usd
CY2021	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	16473000	usd
CY2023	sigi	Unrealized Gain Losson Equity Securities Sold UnrealizedGainLossonEquitySecuritiesSold	5917000	usd
CY2022	sigi	Unrealized Gain Losson Equity Securities Sold UnrealizedGainLossonEquitySecuritiesSold	-21673000	usd
CY2021	sigi	Unrealized Gain Losson Equity Securities Sold UnrealizedGainLossonEquitySecuritiesSold	1408000	usd
CY2022	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-32127000	usd
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	17881000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1221900000	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	1211700000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	502900000	usd
CY2023	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	53300000	usd
CY2022	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	186100000	usd
CY2021	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	99200000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	458412000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93174000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	365238000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	106845000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	22438000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	84407000	usd
CY2023	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Gross UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsGross	60234000	usd
CY2023	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Tax UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsTax	12649000	usd
CY2023	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	47585000	usd
CY2023	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Before Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesBeforeTax	20458000	usd
CY2023	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesTax	4296000	usd
CY2023	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	16162000	usd
CY2023	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Gross DebtSecuritiesAvailableforsaleAllowanceforCreditLossGross	-12898000	usd
CY2023	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Tax DebtSecuritiesAvailableforsaleAllowanceforCreditLossTax	-2709000	usd
CY2023	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Net DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet	-10189000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	174639000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	36674000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	137965000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-19385000	usd
CY2023	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-4070000	usd
CY2023	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-15315000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-3026000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	-635000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-2391000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	16359000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	3435000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	12924000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	158280000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	33239000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	125041000	usd
CY2023	sigi	Comprehensive Income Loss Before Tax ComprehensiveIncomeLossBeforeTax	616692000	usd
CY2023	sigi	Comprehensive Income Loss Tax ComprehensiveIncomeLossTax	126413000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	490279000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	280186000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	55300000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	224886000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-668107000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-140302000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-527805000	usd
CY2022	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Gross UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsGross	-187968000	usd
CY2022	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Tax UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsTax	-39473000	usd
CY2022	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	-148495000	usd
CY2022	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Before Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleBeforeTax	-4000	usd
CY2022	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleTax	-1000	usd
CY2022	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Netof Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleNetofTax	-3000	usd
CY2022	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Before Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesBeforeTax	60048000	usd
CY2022	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesTax	12610000	usd
CY2022	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	47438000	usd
CY2022	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Gross DebtSecuritiesAvailableforsaleAllowanceforCreditLossGross	39169000	usd
CY2022	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Tax DebtSecuritiesAvailableforsaleAllowanceforCreditLossTax	8225000	usd
CY2022	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Net DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet	30944000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-756854000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-158939000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-597915000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-20941000	usd
CY2022	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-4398000	usd
CY2022	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-16543000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-1668000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	-351000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1317000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	19273000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	4047000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	15226000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-776127000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-162986000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-613141000	usd
CY2022	sigi	Comprehensive Income Loss Before Tax ComprehensiveIncomeLossBeforeTax	-495941000	usd
CY2022	sigi	Comprehensive Income Loss Tax ComprehensiveIncomeLossTax	-107686000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-388255000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	505310000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	101473000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	403837000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-151391000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-31793000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-119598000	usd
CY2021	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Gross UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsGross	-9061000	usd
CY2021	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Tax UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsTax	-1902000	usd
CY2021	sigi	Unrealized Gains Losses On Securities With Credit Loss Recognized In Earnings Net UnrealizedGainsLossesOnSecuritiesWithCreditLossRecognizedInEarningsNet	-7159000	usd
CY2021	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Before Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleBeforeTax	11000	usd
CY2021	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleTax	2000	usd
CY2021	sigi	Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Netof Tax AmortizationOfNetUnrealizedGainsLossesOnHeldToMaturityTransferredFromAvailableForSaleNetofTax	9000	usd
CY2021	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Before Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesBeforeTax	-3825000	usd
CY2021	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesTax	-803000	usd
CY2021	sigi	Oci Reclassification Adjustment From Aoci For Write Down Of Securities Net Of Tax OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax	-3022000	usd
CY2021	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Gross DebtSecuritiesAvailableforsaleAllowanceforCreditLossGross	6858000	usd
CY2021	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Tax DebtSecuritiesAvailableforsaleAllowanceforCreditLossTax	1440000	usd
CY2021	sigi	Debt Securities Availableforsale Allowancefor Credit Loss Net DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet	5418000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-157430000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-33060000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-124370000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	21636000	usd
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	4543000	usd
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	17093000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-2772000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTax	-582000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-2190000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax	-24408000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-5125000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-19283000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-133022000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-27935000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-105087000	usd
CY2021	sigi	Comprehensive Income Loss Before Tax ComprehensiveIncomeLossBeforeTax	372288000	usd
CY2021	sigi	Comprehensive Income Loss Tax ComprehensiveIncomeLossTax	73538000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	298750000	usd
CY2023Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	503805000	usd
CY2022Q4	us-gaap	Long Term Debt Fair Value LongTermDebtFairValue	466603000	usd
CY2023Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	2636000	usd
CY2022Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	3718000	usd
CY2023Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	503946000	usd
CY2022Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	504676000	usd
CY2022Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	349255000	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	201681000	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	0	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Issues FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues	0	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	27016000	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	38485000	usd
CY2023	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3	26062000	usd
CY2023Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	551689000	usd
CY2023	sigi	Periodchangeunrealizedgainslossesinearnings Periodchangeunrealizedgainslossesinearnings	-241000	usd
CY2023	sigi	Periodchangeunrealizedgainslossesin Oci PeriodchangeunrealizedgainslossesinOCI	-14652000	usd
CY2021Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	251282000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	200274000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	0	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Issues FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues	0	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	22535000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3	20613000	usd
CY2022	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Out Of Level3 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3	60938000	usd
CY2022Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	349255000	usd
CY2022	sigi	Periodchangeunrealizedgainslossesinearnings Periodchangeunrealizedgainslossesinearnings	3374000	usd
CY2022	sigi	Periodchangeunrealizedgainslossesin Oci PeriodchangeunrealizedgainslossesinOCI	-36359000	usd
CY2023Q4	us-gaap	Other Assets Fair Value Disclosure OtherAssetsFairValueDisclosure	288955000	usd
CY2023Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	551689000	usd
CY2022Q4	us-gaap	Other Assets Fair Value Disclosure OtherAssetsFairValueDisclosure	207936000	usd
CY2022Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	349255000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	21923000	usd
CY2023Q4	sigi	Commercial Mortgage Loan Fair Value CommercialMortgageLoanFairValue	178913000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	29837000	usd
CY2022Q4	sigi	Commercial Mortgage Loan Fair Value CommercialMortgageLoanFairValue	139243000	usd
CY2022Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	16100000	usd
CY2021Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	13600000	usd
CY2023	us-gaap	Premium Receivable Credit Loss Expense Reversal PremiumReceivableCreditLossExpenseReversal	6124000	usd
CY2022	us-gaap	Premium Receivable Credit Loss Expense Reversal PremiumReceivableCreditLossExpenseReversal	6065000	usd
CY2023	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Write Offs Against Allowance PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance	5080000	usd
CY2022	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Write Offs Against Allowance PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance	4978000	usd
CY2023	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Recoveries PremiumsReceivableAllowanceForDoubtfulAccountsRecoveries	1756000	usd
CY2022	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Recoveries PremiumsReceivableAllowanceForDoubtfulAccountsRecoveries	1413000	usd
CY2023Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	18900000	usd
CY2022Q4	us-gaap	Premiums Receivable Allowance For Doubtful Accounts PremiumsReceivableAllowanceForDoubtfulAccounts	16100000	usd
CY2023Q4	sigi	Series20231 Class A Catastrophe Bonds Series20231ClassACatastropheBonds	325000000	usd
CY2023	sigi	Terrorism Risk Insurance Program Companys Estimated Deductible TerrorismRiskInsuranceProgramCompanysEstimatedDeductible	543000000	usd
CY2023	sigi	Terrorism Risk Insurance Program Reimbursed Percentage Maximum TerrorismRiskInsuranceProgramReimbursedPercentageMaximum	0.80
CY2023	sigi	Terrorism Risk Insurance Program Annual Cap TerrorismRiskInsuranceProgramAnnualCap	100000000000	usd
CY2023Q4	sigi	Terrorism Risk Insurance Program Insurer Retainer TerrorismRiskInsuranceProgramInsurerRetainer	0.20
CY2023Q4	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	658525000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1700000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	656825000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	784410000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	782810000	usd
CY2023	sigi	Percentage Of Unpaid Nfip Claims Ceded By Federal Government PercentageOfUnpaidNFIPClaimsCededByFederalGovernment	1
CY2022Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2021Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2023	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	100000	usd
CY2022	us-gaap	Reinsurance Recoverable Credit Loss Expense Reversal ReinsuranceRecoverableCreditLossExpenseReversal	0	usd
CY2023	us-gaap	Reinsurance Loss On Uncollectible Accounts In Period Amount ReinsuranceLossOnUncollectibleAccountsInPeriodAmount	0	usd
CY2022	us-gaap	Reinsurance Loss On Uncollectible Accounts In Period Amount ReinsuranceLossOnUncollectibleAccountsInPeriodAmount	0	usd
CY2023	us-gaap	Reinsurance Recoverable Allowance For Credit Loss Recovery ReinsuranceRecoverableAllowanceForCreditLossRecovery	0	usd
CY2022	us-gaap	Reinsurance Recoverable Allowance For Credit Loss Recovery ReinsuranceRecoverableAllowanceForCreditLossRecovery	0	usd
CY2023Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1700000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	656825000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	782810000	usd
CY2023Q4	us-gaap	Prepaid Reinsurance Premiums PrepaidReinsurancePremiums	203320000	usd
CY2022Q4	us-gaap	Prepaid Reinsurance Premiums PrepaidReinsurancePremiums	172371000	usd
CY2023Q4	sigi	Remaining Reinsurance Balances RemainingReinsuranceBalances	860145000	usd
CY2022Q4	sigi	Remaining Reinsurance Balances RemainingReinsuranceBalances	955181000	usd
CY2023Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1700000	usd
CY2022Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1600000	usd
CY2023Q4	sigi	Collateral Of Reinsurance Recoverables CollateralOfReinsuranceRecoverables	126418000	usd
CY2022Q4	sigi	Collateral Of Reinsurance Recoverables CollateralOfReinsuranceRecoverables	126167000	usd
CY2023	us-gaap	Direct Premiums Written DirectPremiumsWritten	4725459000	usd
CY2022	us-gaap	Direct Premiums Written DirectPremiumsWritten	4068518000	usd
CY2021	us-gaap	Direct Premiums Written DirectPremiumsWritten	3656537000	usd
CY2023	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	23999000	usd
CY2022	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	32320000	usd
CY2021	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	22664000	usd
CY2023	us-gaap	Ceded Premiums Written CededPremiumsWritten	614926000	usd
CY2022	us-gaap	Ceded Premiums Written CededPremiumsWritten	527248000	usd
CY2021	us-gaap	Ceded Premiums Written CededPremiumsWritten	489488000	usd
CY2023	us-gaap	Premiums Written Net PremiumsWrittenNet	4134532000	usd
CY2022	us-gaap	Premiums Written Net PremiumsWrittenNet	3573590000	usd
CY2021	us-gaap	Premiums Written Net PremiumsWrittenNet	3189713000	usd
CY2023	us-gaap	Direct Premiums Earned DirectPremiumsEarned	4386556000	usd
CY2022	us-gaap	Direct Premiums Earned DirectPremiumsEarned	3880522000	usd
CY2021	us-gaap	Direct Premiums Earned DirectPremiumsEarned	3472715000	usd
CY2023	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	25027000	usd
CY2022	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	30742000	usd
CY2021	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	21550000	usd
CY2023	us-gaap	Ceded Premiums Earned CededPremiumsEarned	583977000	usd
CY2022	us-gaap	Ceded Premiums Earned CededPremiumsEarned	537884000	usd
CY2021	us-gaap	Ceded Premiums Earned CededPremiumsEarned	477012000	usd
CY2023	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3827606000	usd
CY2022	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3373380000	usd
CY2021	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3017253000	usd
CY2023	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	2738301000	usd
CY2022	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	2537638000	usd
CY2021	us-gaap	Policyholder Benefits And Claims Incurred Gross PolicyholderBenefitsAndClaimsIncurredGross	2096512000	usd
CY2023	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	19581000	usd
CY2022	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	23160000	usd
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Assumed ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed	13813000	usd
CY2023	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	273597000	usd
CY2022	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	449020000	usd
CY2021	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	296341000	usd
CY2023	us-gaap	Incurred Claims Property Casualty And Liability IncurredClaimsPropertyCasualtyAndLiability	2484285000	usd
CY2022	us-gaap	Incurred Claims Property Casualty And Liability IncurredClaimsPropertyCasualtyAndLiability	2111778000	usd
CY2021	us-gaap	Incurred Claims Property Casualty And Liability IncurredClaimsPropertyCasualtyAndLiability	1813984000	usd
CY2023	sigi	Percentage Of Unpaid Nfip Claims Ceded By Federal Government PercentageOfUnpaidNFIPClaimsCededByFederalGovernment	1
CY2021Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	578641000	usd
CY2023Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	5336911000	usd
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	5144821000	usd
CY2023	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div style="margin-top:8pt"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:56.356%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.384%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.496%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.384%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.496%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.384%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.500%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">($ in thousands)</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2023</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2022</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2021</span></td></tr><tr><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Gross reserves for loss and loss expense, at beginning of year</span></td><td colspan="3" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:0 1pt"></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">5,144,821</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,580,903 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,260,355 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year</span></div></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">757,513</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">578,641 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">554,269 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Net reserves for loss and loss expense, at beginning of year</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">4,387,308</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,002,262 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">3,706,086 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Incurred loss and loss expense for claims occurring in the:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"> </span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2,474,331</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2,190,668 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,896,837 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Prior years</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">9,954</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(78,890)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(82,853)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total incurred loss and loss expense</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2,484,285</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">2,111,778 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,813,984 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Paid loss and loss expense for claims occurring in the:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"> </span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">922,641</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">768,583 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">676,331 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 7.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Prior years</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">1,230,642</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">958,149 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">841,477 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total paid loss and loss expense</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2,153,283</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,726,732 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1,517,808 </span></td><td style="background-color:#cdffcc;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Net reserves for loss and loss expense, at end of year</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">4,718,310</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,387,308 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,002,262 </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cdffcc;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Add: Reinsurance recoverable on unpaid loss and loss expense, at end of year</span></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">618,601</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">757,513 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cdffcc;padding:0 1pt"></td><td colspan="2" style="background-color:#cdffcc;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">578,641 </span></td><td style="background-color:#cdffcc;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Gross reserves for loss and loss expense at end of year</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">5,336,911</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">5,144,821 </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">4,580,903 </span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div>
CY2022Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	5144821000	usd
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	4580903000	usd
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	4260355000	usd
CY2022Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	757513000	usd
CY2021Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	578641000	usd
CY2020Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	554269000	usd
CY2022Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	4387308000	usd
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	4002262000	usd
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	3706086000	usd
CY2023	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	2474331000	usd
CY2022	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	2190668000	usd
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	1896837000	usd
CY2023	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	9954000	usd
CY2022	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	78890000	usd
CY2021	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	82853000	usd
CY2023	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	2484285000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	2111778000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	1813984000	usd
CY2023	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	922641000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	768583000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	676331000	usd
CY2023	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	1230642000	usd
CY2022	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	958149000	usd
CY2021	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	841477000	usd
CY2023	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	2153283000	usd
CY2022	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	1726732000	usd
CY2021	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	1517808000	usd
CY2023Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	4718310000	usd
CY2022Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	4387308000	usd
CY2021Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	4002262000	usd
CY2023Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	618601000	usd
CY2022Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	757513000	usd
CY2021Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	4580903000	usd
CY2023	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	331000000	usd
CY2022	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	385000000	usd
CY2021	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	296200000	usd
CY2023Q4	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	116000000	usd
CY2022Q4	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	91300000	usd
CY2021Q4	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	87000000	usd
CY2023Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	26400000	usd
CY2023Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	19100000	usd
CY2022Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	27768000	usd
CY2022Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	20329000	usd
CY2021Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	27773000	usd
CY2021Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	21075000	usd
CY2020Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	28530000	usd
CY2020Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	21421000	usd
CY2023	us-gaap	Liability For Asbestos And Environmental Claims Gross Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsGrossIncurredLoss1	1064000	usd
CY2023	us-gaap	Liability For Asbestos And Environmental Claims Net Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsNetIncurredLoss1	748000	usd
CY2022	us-gaap	Liability For Asbestos And Environmental Claims Gross Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsGrossIncurredLoss1	704000	usd
CY2022	us-gaap	Liability For Asbestos And Environmental Claims Net Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsNetIncurredLoss1	-205000	usd
CY2021	us-gaap	Liability For Asbestos And Environmental Claims Gross Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsGrossIncurredLoss1	562000	usd
CY2021	us-gaap	Liability For Asbestos And Environmental Claims Net Incurred Loss1 LiabilityForAsbestosAndEnvironmentalClaimsNetIncurredLoss1	37000	usd
CY2023	us-gaap	Liability For Asbestos And Environmental Claims Gross Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsGrossPaymentForClaims	2423000	usd
CY2023	us-gaap	Liability For Asbestos And Environmental Claims Net Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaims	1934000	usd
CY2022	us-gaap	Liability For Asbestos And Environmental Claims Gross Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsGrossPaymentForClaims	709000	usd
CY2022	us-gaap	Liability For Asbestos And Environmental Claims Net Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaims	541000	usd
CY2021	us-gaap	Liability For Asbestos And Environmental Claims Gross Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsGrossPaymentForClaims	195000	usd
CY2021	us-gaap	Liability For Asbestos And Environmental Claims Net Payment For Claims LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaims	383000	usd
CY2023Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	26409000	usd
CY2023Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	19143000	usd
CY2022Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	27768000	usd
CY2022Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	20329000	usd
CY2021Q4	us-gaap	Liability For Asbestos And Environmental Claims Gross LiabilityForAsbestosAndEnvironmentalClaimsGross	27773000	usd
CY2021Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	21075000	usd
CY2023Q4	us-gaap	Shortduration Insurance Contracts Incurred Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet	15332846000	usd
CY2023Q4	us-gaap	Shortduration Insurance Contracts Cumulative Paid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet	11128130000	usd
CY2023Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet	4566037000	usd
CY2023Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet	4566037000	usd
CY2023Q4	us-gaap	Reinsurance Recoverable For Unpaid Claims And Claims Adjustments ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments	618601000	usd
CY2023Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Claims Adjustment Expense Accumulated Unallocated Claim Adjustment Expense ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense	152273000	usd
CY2023Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	5336911000	usd
CY2023Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	2704000	usd
CY2023Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	5986000	usd
CY2023Q4	us-gaap	Long Term Debt LongTermDebt	503946000	usd
CY2022Q4	us-gaap	Long Term Debt LongTermDebt	504676000	usd
CY2023Q4	sigi	Line Of Credit Consolidated Net Worth Requirement LineOfCreditConsolidatedNetWorthRequirement	2200000000	usd
CY2023Q4	sigi	Consolidated Net Worth Actual ConsolidatedNetWorthActual	3300000000	usd
CY2023Q4	sigi	Line Of Credit Debt To Capitalization Ratio Requirement LineOfCreditDebtToCapitalizationRatioRequirement	0.35
CY2023Q4	sigi	Debt To Capitalization Ratio DebtToCapitalizationRatio	0.132
CY2023Q4	us-gaap	Deferred Finance Costs Gross DeferredFinanceCostsGross	3300000	usd
CY2023Q4	sigi	Federal Home Loan Bank Advances General Debt Obligations Disclosures Multiple Amount FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount	20
CY2023	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	4
CY2023Q4	us-gaap	Goodwill Goodwill	7800000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	7800000	usd
CY2023	us-gaap	Net Investment Income NetInvestmentIncome	388650000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	288155000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	326589000	usd
CY2023	us-gaap	Gain Loss On Investments GainLossOnInvestments	-3552000	usd
CY2022	us-gaap	Gain Loss On Investments GainLossOnInvestments	-114808000	usd
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	17599000	usd
CY2023	sigi	Total Investment Revenues TotalInvestmentRevenues	385098000	usd
CY2022	sigi	Total Investment Revenues TotalInvestmentRevenues	173347000	usd
CY2021	sigi	Total Investment Revenues TotalInvestmentRevenues	344188000	usd
CY2023	us-gaap	Revenues Revenues	4232106000	usd
CY2022	us-gaap	Revenues Revenues	3558062000	usd
CY2021	us-gaap	Revenues Revenues	3379164000	usd
CY2023	us-gaap	Net Investment Income NetInvestmentIncome	388650000	usd
CY2022	us-gaap	Net Investment Income NetInvestmentIncome	288155000	usd
CY2021	us-gaap	Net Investment Income NetInvestmentIncome	326589000	usd
CY2023	us-gaap	Gain Loss On Investments GainLossOnInvestments	-3552000	usd
CY2022	us-gaap	Gain Loss On Investments GainLossOnInvestments	-114808000	usd
CY2021	us-gaap	Gain Loss On Investments GainLossOnInvestments	17599000	usd
CY2023	sigi	Total Investment Revenues TotalInvestmentRevenues	385098000	usd
CY2022	sigi	Total Investment Revenues TotalInvestmentRevenues	173347000	usd
CY2021	sigi	Total Investment Revenues TotalInvestmentRevenues	344188000	usd
CY2023	sigi	Taxoninvestmentincome Taxoninvestmentincome	78369000	usd
CY2022	sigi	Taxoninvestmentincome Taxoninvestmentincome	31846000	usd
CY2021	sigi	Taxoninvestmentincome Taxoninvestmentincome	67284000	usd
CY2023	sigi	Total Investment Income After Federal Income Tax TotalInvestmentIncomeAfterFederalIncomeTax	306729000	usd
CY2022	sigi	Total Investment Income After Federal Income Tax TotalInvestmentIncomeAfterFederalIncomeTax	141501000	usd
CY2021	sigi	Total Investment Income After Federal Income Tax TotalInvestmentIncomeAfterFederalIncomeTax	276904000	usd
CY2023	sigi	Total Investment Revenues TotalInvestmentRevenues	385098000	usd
CY2022	sigi	Total Investment Revenues TotalInvestmentRevenues	173347000	usd
CY2021	sigi	Total Investment Revenues TotalInvestmentRevenues	344188000	usd
CY2023	us-gaap	Interest Expense Debt InterestExpenseDebt	28799000	usd
CY2022	us-gaap	Interest Expense Debt InterestExpenseDebt	28847000	usd
CY2021	us-gaap	Interest Expense Debt InterestExpenseDebt	29165000	usd
CY2023	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	30686000	usd
CY2022	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	31116000	usd
CY2021	us-gaap	Operating Costs And Expenses OperatingCostsAndExpenses	28305000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	458412000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	280186000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	505310000	usd
CY2023	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9200000	usd
CY2022	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9200000	usd
CY2021	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	9353000	usd
CY2023	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	449212000	usd
CY2022	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	270986000	usd
CY2021	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	495957000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	356038000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	215686000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	394484000	usd
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	60631000	shares
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	60407000	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	60183000	shares
CY2023	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	338000	shares
CY2022	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	468000	shares
CY2021	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	484000	shares
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	60969000	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	60875000	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	60667000	shares
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.87
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.57
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.55
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.84
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.54
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.50
CY2023	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2023	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	96267000	usd
CY2022	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	58839000	usd
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	106115000	usd
CY2023	sigi	Income Tax Reconciliation Tax Advantaged Interest Income IncomeTaxReconciliationTaxAdvantagedInterestIncome	2229000	usd
CY2022	sigi	Income Tax Reconciliation Tax Advantaged Interest Income IncomeTaxReconciliationTaxAdvantagedInterestIncome	4087000	usd
CY2021	sigi	Income Tax Reconciliation Tax Advantaged Interest Income IncomeTaxReconciliationTaxAdvantagedInterestIncome	4514000	usd
CY2023	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	273000	usd
CY2022	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	469000	usd
CY2021	us-gaap	Income Tax Reconciliation Deductions Dividends IncomeTaxReconciliationDeductionsDividends	558000	usd
CY2023	sigi	Federal Income Tax Expense Benefit Relatedto Executive Compensation FederalIncomeTaxExpenseBenefitRelatedtoExecutiveCompensation	-1989000	usd
CY2022	sigi	Federal Income Tax Expense Benefit Relatedto Executive Compensation FederalIncomeTaxExpenseBenefitRelatedtoExecutiveCompensation	-1848000	usd
CY2021	sigi	Federal Income Tax Expense Benefit Relatedto Executive Compensation FederalIncomeTaxExpenseBenefitRelatedtoExecutiveCompensation	-2469000	usd
CY2023	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-1804000	usd
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-893000	usd
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	-693000	usd
CY2023	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-776000	usd
CY2022	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	62000	usd
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1346000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	93174000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	55300000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	101473000	usd
CY2023	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	449212000	usd
CY2022	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	270986000	usd
CY2021	sigi	Income Available To Common Stockholders Before Tax IncomeAvailableToCommonStockholdersBeforeTax	495957000	usd
CY2023	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.207
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.204
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.205
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	73175000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	65907000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	89413000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	76513000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	13777000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	7064000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	6736000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	6384000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	74183000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	110857000	usd
CY2023Q4	sigi	Temporary Investments Write Downs Dta TemporaryInvestmentsWriteDownsDTA	7560000	usd
CY2022Q4	sigi	Temporary Investments Write Downs Dta TemporaryInvestmentsWriteDownsDTA	12480000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	8080000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	9824000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	272924000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	289029000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	89221000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	77411000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	33309000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	26713000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	10157000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	12172000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	132687000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	116296000	usd
CY2023Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	2330656000	usd
CY2023	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	3827606000	usd
CY2023	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	385098000	usd
CY2023	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	2484285000	usd
CY2023	sigi	Change In Defined Benefit Plan Discount Rate ChangeInDefinedBenefitPlanDiscountRate	19
CY2023Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2022Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2023Q4	sigi	Percent Hedge Against Projected Benefit Obligation PercentHedgeAgainstProjectedBenefitObligation	0.90
CY2023	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23000000.0	usd
CY2022	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	23600000	usd
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	22300000	usd
CY2023	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	6400000	usd
CY2022	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5600000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5100000	usd
CY2023	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	16600000	usd
CY2022	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	18000000.0	usd
CY2021	us-gaap	Allocated Share Based Compensation Expense Net Of Tax AllocatedShareBasedCompensationExpenseNetOfTax	17200000	usd
CY2023Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2023Q4	sigi	Preferred Stock Shares Issued Sigi PreferredStockSharesIssuedSIGI	8000000.0	shares
CY2023Q4	us-gaap	Preferred Stock Liquidation Preference Value PreferredStockLiquidationPreferenceValue	25000	usd
CY2023Q4	us-gaap	Preferred Stock Redemption Price Per Share PreferredStockRedemptionPricePerShare	25000
CY2023Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	100000000	usd
CY2022	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	165159	shares
CY2023	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	12400000	usd
CY2023Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	84200000	usd
CY2023Q4	sigi	Equity Ownership Percentage Of Director Of Parent Of Rue Insurance EquityOwnershipPercentageOfDirectorOfParentOfRueInsurance	1
CY2022	sigi	Related Party Transactions Contributions To Foundation RelatedPartyTransactionsContributionsToFoundation	300000	usd
CY2021	sigi	Related Party Transactions Contributions To Foundation RelatedPartyTransactionsContributionsToFoundation	1300000	usd
CY2023	us-gaap	Operating Lease Cost OperatingLeaseCost	7409000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	8148000	usd
CY2023	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	2692000	usd
CY2022	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	2440000	usd
CY2023	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	66000	usd
CY2022	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	46000	usd
CY2023	sigi	Finance Lease Expense FinanceLeaseExpense	2758000	usd
CY2022	sigi	Finance Lease Expense FinanceLeaseExpense	2486000	usd
CY2023	us-gaap	Variable Lease Cost VariableLeaseCost	996000	usd
CY2022	us-gaap	Variable Lease Cost VariableLeaseCost	1384000	usd
CY2023	us-gaap	Short Term Lease Cost ShortTermLeaseCost	411000	usd
CY2022	us-gaap	Short Term Lease Cost ShortTermLeaseCost	166000	usd
CY2023Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y
CY2023Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y
CY2022Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y
CY2023Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.028
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.026
CY2023Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.035
CY2022Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.012
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	41256000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	42403000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	43675000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	44505000	usd
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	2605000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	3713000	usd
CY2023Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	2636000	usd
CY2022Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	3718000	usd
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	104847111	shares
CY2023Q4	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	44586870	shares
CY2022Q4	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	44508211	shares
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	3002000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	7624000	usd
CY2023Q4	sigi	Total Leases Due Next12 Months TotalLeasesDueNext12Months	10626000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	2859000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	7749000	usd
CY2023Q4	sigi	Total Leases Due In Two Years TotalLeasesDueInTwoYears	10608000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	2482000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	7413000	usd
CY2023Q4	sigi	Total Leases Due In Three Years TotalLeasesDueInThreeYears	9895000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	702000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	7109000	usd
CY2023Q4	sigi	Total Leases Due In Four Years TotalLeasesDueInFourYears	7811000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	0	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	6889000	usd
CY2023Q4	sigi	Total Leases Due In Five Years TotalLeasesDueInFiveYears	6889000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	0	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	18605000	usd
CY2023Q4	sigi	Total Leases Due Thereafter TotalLeasesDueThereafter	18605000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	9045000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	55389000	usd
CY2023Q4	sigi	Total Minimum Payment Required TotalMinimumPaymentRequired	64434000	usd
CY2023Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	112000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	4221000	usd
CY2023Q4	sigi	Totalimputedinterest Totalimputedinterest	4333000	usd
CY2023Q4	sigi	Finance Lease Liability Not Yet Commenced FinanceLeaseLiabilityNotYetCommenced	6297000	usd
CY2023Q4	sigi	Operating Lease Liability Not Yet Commenced OperatingLeaseLiabilityNotYetCommenced	7493000	usd
CY2023Q4	sigi	Totalleaseliabilitynotyetcommenced Totalleaseliabilitynotyetcommenced	13790000	usd
CY2023Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	2636000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	43675000	usd
CY2023Q4	sigi	Totalleaseliability Totalleaseliability	46311000	usd
CY2023Q4	sigi	Purchase Amount Of Annuities PurchaseAmountOfAnnuities	30800000	usd
CY2023Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	424864000	usd
CY2023Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	5336911000	usd
CY2023Q4	sigi	Statutory Accounting Practices Statutory Unassigned Surplus StatutoryAccountingPracticesStatutoryUnassignedSurplus	2176700000	usd
CY2022Q4	sigi	Statutory Accounting Practices Statutory Unassigned Surplus StatutoryAccountingPracticesStatutoryUnassignedSurplus	1908100000	usd
CY2023Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	2742300000	usd
CY2022Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	2473700000	usd
CY2023	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	318800000	usd
CY2022	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	264400000	usd
CY2021	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	338300000	usd
CY2023Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments With Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithRegulatoryApproval	316200000	usd
CY2023	sigi	Maximum Borrowing Percentage MaximumBorrowingPercentage	0.10
CY2023Q4	sigi	New Jersey Dividend Restriction NewJerseyDividendRestriction	0.10
CY2023Q4	sigi	New York Dividend Restriction NewYorkDividendRestriction	0.10
CY2023Q4	sigi	Dividend Restriction New York DividendRestrictionNewYork	1
CY2023	us-gaap	Cash Dividends Paid To Parent Company CashDividendsPaidToParentCompany	80000000.0	usd
CY2023Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments With Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithRegulatoryApproval	316200000	usd
CY2023	dei	Auditor Firm AuditorFirmId	185
CY2023Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Cost SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCost	9071424000	usd
CY2023Q4	us-gaap	Summary Of Investments Other Than Investments In Related Parties Carrying Amount SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount	8693729000	usd
CY2022Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0
CY2023Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0
CY2023Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	8000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2022Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	8000	shares
CY2023Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25000
CY2022Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	25000
CY2022Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	2
CY2023Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	2
CY2023Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	360000000	shares
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	360000000	shares
CY2023Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	105223307	shares
CY2023	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	796182000	usd
CY2023	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	414340000	usd
CY2023	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	4134532000	usd
CY2023	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	414340000	usd
CY2023	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	433742000	usd
CY2023	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	414340000	usd
CY2022Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	368624000	usd
CY2022Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	5144821000	usd
CY2022Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	1992781000	usd
CY2022	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	3373380000	usd
CY2022	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	173347000	usd
CY2022	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	2111778000	usd
CY2022	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	705822000	usd
CY2022	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	388978000	usd
CY2022	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	3573590000	usd
CY2022	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	388978000	usd
CY2022	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	400313000	usd
CY2022	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	388978000	usd
CY2021Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	326915000	usd
CY2021Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	4580903000	usd
CY2021Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	1803207000	usd
CY2021	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	3017253000	usd
CY2021	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	344188000	usd
CY2021	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	1813984000	usd
CY2021	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	626469000	usd
CY2021	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	358208000	usd
CY2021	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	3189713000	usd
CY2021	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	358208000	usd
CY2021	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	375931000	usd
CY2021	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	358208000	usd
CY2023	us-gaap	Direct Premiums Earned DirectPremiumsEarned	4386556000	usd
CY2023	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	25027000	usd
CY2023	us-gaap	Ceded Premiums Earned CededPremiumsEarned	583977000	usd
CY2023	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3827606000	usd
CY2023	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.01
CY2022	us-gaap	Direct Premiums Earned DirectPremiumsEarned	3880522000	usd
CY2022	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	30742000	usd
CY2022	us-gaap	Ceded Premiums Earned CededPremiumsEarned	537884000	usd
CY2022	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3373380000	usd
CY2022	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.01
CY2021	us-gaap	Direct Premiums Earned DirectPremiumsEarned	3472715000	usd
CY2021	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	21550000	usd
CY2021	us-gaap	Ceded Premiums Earned CededPremiumsEarned	477012000	usd
CY2021	us-gaap	Premiums Earned Net Property And Casualty PremiumsEarnedNetPropertyAndCasualty	3017253000	usd
CY2021	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.01
CY2022Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	17700000	usd
CY2021Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	15200000	usd
CY2020Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	22777000	usd
CY2023	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	7980000	usd
CY2022	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	7478000	usd
CY2021	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	1766000	usd
CY2023	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	5080000	usd
CY2022	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	4978000	usd
CY2021	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	9343000	usd
CY2023Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	20600000	usd
CY2022Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	17700000	usd
CY2021Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	15200000	usd

Files In Submission

Name	View Source	Status
FilingSummary.xml	Edgar Link	unprocessable
sigi-20231231_cal.xml	Edgar Link	unprocessable
0000230557-24-000005-index-headers.html	Edgar Link	pending
0000230557-24-000005-index.html	Edgar Link	pending
0000230557-24-000005.txt	Edgar Link	pending
0000230557-24-000005-xbrl.zip	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R100.htm	Edgar Link	pending
R101.htm	Edgar Link	pending
R102.htm	Edgar Link	pending
R103.htm	Edgar Link	pending
R104.htm	Edgar Link	pending
R105.htm	Edgar Link	pending
R106.htm	Edgar Link	pending
R107.htm	Edgar Link	pending
R108.htm	Edgar Link	pending
R109.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R110.htm	Edgar Link	pending
R111.htm	Edgar Link	pending
R112.htm	Edgar Link	pending
R113.htm	Edgar Link	pending
R114.htm	Edgar Link	pending
R115.htm	Edgar Link	pending
R116.htm	Edgar Link	pending
R117.htm	Edgar Link	pending
R118.htm	Edgar Link	pending
R119.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R120.htm	Edgar Link	pending
R121.htm	Edgar Link	pending
R122.htm	Edgar Link	pending
R123.htm	Edgar Link	pending
R124.htm	Edgar Link	pending
R125.htm	Edgar Link	pending
R126.htm	Edgar Link	pending
R127.htm	Edgar Link	pending
R128.htm	Edgar Link	pending
R129.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R130.htm	Edgar Link	pending
R131.htm	Edgar Link	pending
R132.htm	Edgar Link	pending
R133.htm	Edgar Link	pending
R134.htm	Edgar Link	pending
R135.htm	Edgar Link	pending
R136.htm	Edgar Link	pending
R137.htm	Edgar Link	pending
R138.htm	Edgar Link	pending
R139.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R140.htm	Edgar Link	pending
R141.htm	Edgar Link	pending
R142.htm	Edgar Link	pending
R143.htm	Edgar Link	pending
R144.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R87.htm	Edgar Link	pending
R88.htm	Edgar Link	pending
R89.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
R90.htm	Edgar Link	pending
R91.htm	Edgar Link	pending
R92.htm	Edgar Link	pending
R93.htm	Edgar Link	pending
R94.htm	Edgar Link	pending
R95.htm	Edgar Link	pending
R96.htm	Edgar Link	pending
R97.htm	Edgar Link	pending
R98.htm	Edgar Link	pending
R99.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
sigi-20231231.htm	Edgar Link	pending
sigi-20231231.xsd	Edgar Link	pending
sigi-20231231_g1.jpg	Edgar Link	pending
sigi-20231231_g2.gif	Edgar Link	pending
sigi-20231231_g3.jpg	Edgar Link	pending
sigi-20231231_def.xml	Edgar Link	unprocessable
sigi-20231231_lab.xml	Edgar Link	unprocessable
sigi-20231231_pre.xml	Edgar Link	unprocessable
sigi-20231231_htm.xml	Edgar Link	completed
sigi-ex1014_12312023xq4.htm	Edgar Link	pending
sigi-ex1027_12312023xq4.htm	Edgar Link	pending
sigi-ex1028_12312023xq4.htm	Edgar Link	pending
sigi-ex21_12312023xq4.htm	Edgar Link	pending
sigi-ex231_12312023xq4.htm	Edgar Link	pending
sigi-ex2410poa_12312023xq4.htm	Edgar Link	pending
sigi-ex2411poa_12312023xq4.htm	Edgar Link	pending
sigi-ex2412poa_12312023xq4.htm	Edgar Link	pending
sigi-ex241poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex242poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex243poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex244poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex245poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex246poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex247poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex248poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex249poa_12312023xq4x.htm	Edgar Link	pending
sigi-ex311_12312023xq4.htm	Edgar Link	pending
sigi-ex312_12312023xq4.htm	Edgar Link	pending
sigi-ex321_12312023xq4.htm	Edgar Link	pending
sigi-ex322_12312023xq4.htm	Edgar Link	pending
sigi-ex971_12312023xq4.htm	Edgar Link	pending
sigi-ex991_12312023xq4.htm	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$SIGI
Selective Insurance Group Inc Stock $sigi

2024 Q1 Form 10-K Financial Statement

#000023055724000005 Filed on February 09, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SIGI Selective Insurance Group Inc Stock $sigi

2024 Q1 Form 10-K Financial Statement

#000023055724000005 Filed on February 09, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SIGI
Selective Insurance Group Inc Stock $sigi