$WRB
BERKLEY W R CORP Stock $wrb

$wrb Overview Financials Valuation SEC Filings Company Website

2017 Q4 Form 10-K Financial Statement

#000001154419000016 Filed on February 22, 2019

Income Statement

Concept	2017 Q4	2017 Q3	2017 Q2
Revenue	$1.935B	$2.031B	$1.848B
YoY Change	-1.85%	0.58%	-0.42%
Cost Of Revenue		$1.081B	$964.7M
YoY Change		11.94%	0.06%
Gross Profit		$950.2M	$883.4M
YoY Change		-9.84%	-0.94%
Gross Profit Margin		46.78%	47.8%
Selling, General & Admin	$32.50M	$32.50M	$34.90M
YoY Change	-7.14%	0.31%	-7.18%
% of Gross Profit		3.42%	3.95%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$34.90M	$33.40M	$26.60M
YoY Change	106.51%	49.78%	59.28%
% of Gross Profit		3.52%	3.01%
Operating Expenses	$1.696B	$1.767B	$1.643B
YoY Change	-0.45%	6.85%	-1.93%
Operating Profit		-$816.4M	-$759.9M
YoY Change		36.2%	-3.05%
Interest Expense	-$37.90M	$36.82M	$36.80M
YoY Change	3.84%	-0.6%	5.89%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$201.4M	$226.1M	$161.0M
YoY Change	-13.11%	-31.81%	1.67%
Income Tax	$65.90M	$63.30M	$51.39M
% Of Pretax Income	32.72%	27.99%	31.93%
Net Earnings	$154.6M	$162.1M	$109.0M
YoY Change	1.18%	-26.56%	0.03%
Net Earnings / Revenue	7.99%	7.98%	5.9%
Basic Earnings Per Share	$1.22	$1.29	$0.87
Diluted Earnings Per Share	$1.21	$1.26	$0.85
COMMON SHARES
Basic Shares Outstanding	121.8M shares	125.8M shares	125.3M shares
Diluted Shares Outstanding		128.9M shares	128.6M shares

Balance Sheet

Concept	2017 Q4	2017 Q3	2017 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$950.5M	$774.0M	$788.4M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$189.0M	$297.0M	$165.0M
YoY Change	-61.03%	59.68%	-52.72%
LONG-TERM ASSETS
Property, Plant & Equipment	$423.0M	$399.9M	$425.0M
YoY Change	21.04%	14.86%	22.82%
Goodwill	$178.9M	$173.4M	$144.9M
YoY Change	23.83%	29.28%	-6.1%
Intangibles
YoY Change
Long-Term Investments	$1.156B	$1.120B	$1.191B
YoY Change	-3.54%	-9.08%	-1.18%
Other Assets
YoY Change
Total Long-Term Assets	$24.11B	$24.04B	$23.83B
YoY Change	5.45%	3.8%	5.08%
TOTAL ASSETS
Total Short-Term Assets	$189.0M	$297.0M	$165.0M
Total Long-Term Assets	$24.11B	$24.04B	$23.83B
Total Assets	$24.30B	$24.34B	$23.99B
YoY Change	4.07%	4.24%	4.2%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses
YoY Change
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	$11.00M
YoY Change
LONG-TERM LIABILITIES
Long-Term Debt	$2.497B	$2.488B	$2.487B
YoY Change	0.36%	-0.08%	-1.93%
Other Long-Term Liabilities	$1.046B	$968.0M	$1.114B
YoY Change	8.17%	-5.93%	17.39%
Total Long-Term Liabilities	$3.543B	$3.456B	$3.601B
YoY Change	2.55%	-1.79%	3.33%
TOTAL LIABILITIES
Total Short-Term Liabilities	$11.00M
Total Long-Term Liabilities	$3.543B	$3.456B	$3.601B
Total Liabilities	$18.85B	$18.87B	$18.67B
YoY Change	3.17%	2.62%	3.21%
SHAREHOLDERS EQUITY
Retained Earnings	$6.957B	$6.880B	$6.735B
YoY Change	5.47%	5.53%	5.63%
Common Stock	$1.095B	$1.088B	$1.105B
YoY Change	1.0%	1.22%	3.4%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$2.709B	$2.691B	$2.687B
YoY Change	0.76%	1.22%	3.37%
Treasury Stock Shares	113.6M shares	113.3M shares	113.8M shares
Shareholders Equity	$5.411B	$5.431B	$5.287B
YoY Change
Total Liabilities & Shareholders Equity	$24.30B	$24.34B	$23.99B
YoY Change	4.07%	4.24%	4.2%

Cashflow Statement

Concept	2017 Q4	2017 Q3	2017 Q2
OPERATING ACTIVITIES
Net Income	$154.6M	$162.1M	$109.0M
YoY Change	1.18%	-26.56%	0.03%
Depreciation, Depletion And Amortization	$34.90M	$33.40M	$26.60M
YoY Change	106.51%	49.78%	59.28%
Cash From Operating Activities	$189.0M	$297.0M	$149.4M
YoY Change	55.05%	-24.66%	-21.98%
INVESTING ACTIVITIES
Capital Expenditures	-$118.5M	-$33.70M	-$138.4M
YoY Change	13.61%	-69.36%	99.14%
Acquisitions
YoY Change
Other Investing Activities	$219.1M	-$176.0M	$183.8M
YoY Change	96.33%	-32.93%	-172.25%
Cash From Investing Activities	$100.6M	-$209.8M	$45.50M
YoY Change	1259.46%	-43.68%	-114.05%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-107.7M	-108.9M	-15.70M
YoY Change	-43.7%	12.15%	-106.18%
NET CHANGE
Cash From Operating Activities	189.0M	297.0M	149.4M
Cash From Investing Activities	100.6M	-209.8M	45.50M
Cash From Financing Activities	-107.7M	-108.9M	-15.70M
Net Change In Cash	181.9M	-21.70M	179.2M
YoY Change	-393.39%	-71.22%	47.13%
FREE CASH FLOW
Cash From Operating Activities	$189.0M	$297.0M	$149.4M
Capital Expenditures	-$118.5M	-$33.70M	-$138.4M
Free Cash Flow	$307.5M	$330.7M	$287.8M
YoY Change	35.94%	-34.41%	10.27%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2018	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2018	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2018	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2018
CY2018	dei	Document Period End Date DocumentPeriodEndDate	2018-12-31
CY2018	dei	Document Type DocumentType	10-K
CY2018	dei	Entity Central Index Key EntityCentralIndexKey	0000011544
CY2018	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2018	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2018	dei	Entity Registrant Name EntityRegistrantName	BERKLEY W R CORP
CY2018	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2018	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
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CY2017Q4	us-gaap	Taxes Payable Current And Noncurrent TaxesPayableCurrentAndNoncurrent	11327000	USD
CY2018Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	0	USD
CY2017Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	86764000	USD
CY2018Q4	us-gaap	Other Liabilities OtherLiabilities	1005184000	USD
CY2017Q4	us-gaap	Other Liabilities OtherLiabilities	981987000	USD
CY2018Q4	wrb	Senior Notes And Other Debt SeniorNotesAndOtherDebt	1882028000	USD
CY2017Q4	wrb	Senior Notes And Other Debt SeniorNotesAndOtherDebt	1769052000	USD
CY2018Q4	us-gaap	Junior Subordinated Notes JuniorSubordinatedNotes	907491000	USD
CY2017Q4	us-gaap	Junior Subordinated Notes JuniorSubordinatedNotes	728218000	USD
CY2018Q4	us-gaap	Liabilities Liabilities	19416179000	USD
CY2017Q4	us-gaap	Liabilities Liabilities	18848754000	USD
CY2018Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2017Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2018Q4	us-gaap	Common Stock Value CommonStockValue	47024000	USD
CY2017Q4	us-gaap	Common Stock Value CommonStockValue	47024000	USD
CY2018Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	1063144000	USD
CY2017Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	1048283000	USD
CY2018Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	7558619000	USD
CY2017Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	6956882000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-510470000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	68541000	USD
CY2018Q4	us-gaap	Treasury Stock Value TreasuryStockValue	2720466000	USD
CY2017Q4	us-gaap	Treasury Stock Value TreasuryStockValue	2709386000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	5437851000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	5411344000	USD
CY2018Q4	us-gaap	Minority Interest MinorityInterest	41947000	USD
CY2017Q4	us-gaap	Minority Interest MinorityInterest	39819000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5479798000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5451163000	USD
CY2018Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	24895977000	USD
CY2017Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	24299917000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	640749000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	549094000	USD
CY2016	us-gaap	Net Income Loss NetIncomeLoss	601916000	USD
CY2018	us-gaap	Gain Loss On Investments GainLossOnInvestments	154488000	USD
CY2017	us-gaap	Gain Loss On Investments GainLossOnInvestments	335858000	USD
CY2016	us-gaap	Gain Loss On Investments GainLossOnInvestments	267005000	USD
CY2018	us-gaap	Depreciation And Amortization DepreciationAndAmortization	131108000	USD
CY2017	us-gaap	Depreciation And Amortization DepreciationAndAmortization	112956000	USD
CY2016	us-gaap	Depreciation And Amortization DepreciationAndAmortization	86051000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	8317000	USD
CY2017	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	4243000	USD
CY2016	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	1569000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	109349000	USD
CY2017	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	69333000	USD
CY2016	us-gaap	Income Loss From Equity Method Investments Net Of Dividends Or Distributions IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions	99301000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	36591000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	40490000	USD
CY2016	us-gaap	Share Based Compensation ShareBasedCompensation	37174000	USD
CY2018	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	19093000	USD
CY2017	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	4896000	USD
CY2016	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	10633000	USD
CY2018	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	43813000	USD
CY2017	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	67752000	USD
CY2016	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	60403000	USD
CY2018	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	165287000	USD
CY2017	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	66542000	USD
CY2016	us-gaap	Increase Decrease In Reinsurance Recoverable IncreaseDecreaseInReinsuranceRecoverable	235455000	USD
CY2018	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	-7788000	USD
CY2017	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	-30343000	USD
CY2016	us-gaap	Increase Decrease In Deferred Policy Acquisition Costs IncreaseDecreaseInDeferredPolicyAcquisitionCosts	25912000	USD
CY2018	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-11950000	USD
CY2017	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	25859000	USD
CY2016	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	42632000	USD
CY2018	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	74761000	USD
CY2017	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	16893000	USD
CY2016	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-9012000	USD
CY2018	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	339015000	USD
CY2017	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	438530000	USD
CY2016	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	572196000	USD
CY2018	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	84142000	USD
CY2017	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	4160000	USD
CY2016	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	149683000	USD
CY2018	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-48770000	USD
CY2017	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	66482000	USD
CY2016	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	46852000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	620199000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	710883000	USD
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	848376000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	3525149000	USD
CY2017	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	4035162000	USD
CY2016	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	2440310000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	497989000	USD
CY2017	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	195270000	USD
CY2016	us-gaap	Proceeds From Sale Of Available For Sale Securities Equity ProceedsFromSaleOfAvailableForSaleSecuritiesEquity	143042000	USD
CY2018	us-gaap	Payments For Proceeds From Businesses And Interest In Affiliates PaymentsForProceedsFromBusinessesAndInterestInAffiliates	79635000	USD
CY2017	us-gaap	Payments For Proceeds From Businesses And Interest In Affiliates PaymentsForProceedsFromBusinessesAndInterestInAffiliates	-247404000	USD
CY2016	us-gaap	Payments For Proceeds From Businesses And Interest In Affiliates PaymentsForProceedsFromBusinessesAndInterestInAffiliates	-142601000	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	2676455000	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	3556744000	USD
CY2016	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	2189365000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	6677753000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	7940957000	USD
CY2016	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	5541202000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	85610000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	27522000	USD
CY2016	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	202736000	USD
CY2018	us-gaap	Payments To Acquire Real Estate PaymentsToAcquireRealEstate	514064000	USD
CY2017	us-gaap	Payments To Acquire Real Estate PaymentsToAcquireRealEstate	236039000	USD
CY2016	us-gaap	Payments To Acquire Real Estate PaymentsToAcquireRealEstate	299123000	USD
CY2018	us-gaap	Payments For Proceeds From Loans Receivable PaymentsForProceedsFromLoansReceivable	13204000	USD
CY2017	us-gaap	Payments For Proceeds From Loans Receivable PaymentsForProceedsFromLoansReceivable	-27135000	USD
CY2016	us-gaap	Payments For Proceeds From Loans Receivable PaymentsForProceedsFromLoansReceivable	-166327000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	49860000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	115719000	USD
CY2016	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	50829000	USD
CY2018	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	-4262000	USD
CY2017	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	4372000	USD
CY2016	us-gaap	Increase Decrease In Broker Dealer Related Receivables Payables Net IncreaseDecreaseInBrokerDealerRelatedReceivablesPayablesNet	-20992000	USD
CY2018	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	8664000	USD
CY2017	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	0	USD
CY2016	us-gaap	Proceeds From Divestiture Of Businesses Net Of Cash Divested ProceedsFromDivestitureOfBusinessesNetOfCashDivested	250216000	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	6637000	USD
CY2017	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	70570000	USD
CY2016	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	53451000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-714244000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-333464000	USD
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-794488000	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	294562000	USD
CY2017	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	6983000	USD
CY2016	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	388769000	USD
CY2018	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-4524000	USD
CY2017	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-20000	USD
CY2016	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-75487000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	254951000	USD
CY2017	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	188199000	USD
CY2016	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	183999000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	24750000	USD
CY2017	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	47807000	USD
CY2016	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	132392000	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-17740000	USD
CY2017	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-6043000	USD
CY2016	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-3823000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-7403000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-235086000	USD
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-6932000	USD
CY2018	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-31421000	USD
CY2017	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	12853000	USD
CY2016	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	-15302000	USD
CY2018	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-132869000	USD
CY2017	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	155186000	USD
CY2016	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	31654000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	950471000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	795285000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	763631000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	817602000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	950471000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	795285000	USD
CY2018	us-gaap	Income Taxes Paid IncomeTaxesPaid	186000000	USD
CY2018Q4	wrb	Increase Decrease In Earned Unbilled Audit Premiums IncreaseDecreaseInEarnedUnbilledAuditPremiums	-4000000	USD
CY2017Q4	wrb	Increase Decrease In Earned Unbilled Audit Premiums IncreaseDecreaseInEarnedUnbilledAuditPremiums	8000000	USD
CY2016Q4	wrb	Increase Decrease In Earned Unbilled Audit Premiums IncreaseDecreaseInEarnedUnbilledAuditPremiums	8000000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	145000000	USD
CY2016	us-gaap	Interest Paid Net InterestPaidNet	137000000	USD
CY2018Q4	us-gaap	Deposit Contracts Liabilities DepositContractsLiabilities	45000000	USD
CY2017Q4	us-gaap	Deposit Contracts Liabilities DepositContractsLiabilities	47000000	USD
CY2018	us-gaap	Depreciation Depreciation	54000000	USD
CY2017	us-gaap	Depreciation Depreciation	50000000	USD
CY2016	us-gaap	Depreciation Depreciation	47000000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	155000000	USD
CY2017	us-gaap	Income Taxes Paid IncomeTaxesPaid	207000000	USD
CY2016	us-gaap	Income Taxes Paid IncomeTaxesPaid	232000000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-302737000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	-112099000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-414836000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-50410000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-50410000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-252327000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-112099000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-364426000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-69425000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentBeforeTax	64706000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-4719000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-17673000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Foreign Currency Translation Adjustment Tax OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-17673000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-51752000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	64706000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	12954000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Amortized Cost Before Other Than Temporary Impairment HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment	78635000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	12808000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	91443000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	78635000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	13596057000	USD
CY2018Q4	wrb	Available For Sale Securities Debt Securities Gross Unrealized Gain AvailableForSaleSecuritiesDebtSecuritiesGrossUnrealizedGain	147683000	USD
CY2018Q4	wrb	Available For Sale Securities Debt Securities Gross Unrealized Losses AvailableForSaleSecuritiesDebtSecuritiesGrossUnrealizedLosses	215563000	USD
CY2018Q4	wrb	Available For Sale Securities Debt Securities Fair Value AvailableForSaleSecuritiesDebtSecuritiesFairValue	13528177000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	13528177000	USD
CY2018Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Amortized Cost DebtSecuritiesAvailableforsaleandHeldtomaturityAmortizedCost	13674692000	USD
CY2018Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Gross Unrealized Gains DebtSecuritiesAvailableforsaleandHeldtomaturityGrossUnrealizedGains	160491000	USD
CY2018Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Gross Unrealized Losses DebtSecuritiesAvailableforsaleandHeldtomaturityGrossUnrealizedLosses	215563000	USD
CY2018Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Fair Value DebtSecuritiesAvailableforsaleandHeldtomaturityFairValue	13619620000	USD
CY2018Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity DebtSecuritiesAvailableforsaleandHeldtomaturity	13606812000	USD
CY2017Q4	us-gaap	Held To Maturity Securities Amortized Cost Before Other Than Temporary Impairment HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment	79332000	USD
CY2017Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	15726000	USD
CY2017Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2017Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	95058000	USD
CY2017Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	79332000	USD
CY2017Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	13242580000	USD
CY2017Q4	wrb	Available For Sale Securities Debt Securities Gross Unrealized Gain AvailableForSaleSecuritiesDebtSecuritiesGrossUnrealizedGain	289567000	USD
CY2017Q4	wrb	Available For Sale Securities Debt Securities Gross Unrealized Losses AvailableForSaleSecuritiesDebtSecuritiesGrossUnrealizedLosses	60229000	USD
CY2017Q4	wrb	Available For Sale Securities Debt Securities Fair Value AvailableForSaleSecuritiesDebtSecuritiesFairValue	13471918000	USD
CY2017Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	13471918000	USD
CY2017Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Amortized Cost DebtSecuritiesAvailableforsaleandHeldtomaturityAmortizedCost	13321912000	USD
CY2017Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Gross Unrealized Gains DebtSecuritiesAvailableforsaleandHeldtomaturityGrossUnrealizedGains	305293000	USD
CY2017Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Gross Unrealized Losses DebtSecuritiesAvailableforsaleandHeldtomaturityGrossUnrealizedLosses	60229000	USD
CY2017Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity Fair Value DebtSecuritiesAvailableforsaleandHeldtomaturityFairValue	13566976000	USD
CY2017Q4	wrb	Debt Securities Availableforsaleand Heldtomaturity DebtSecuritiesAvailableforsaleandHeldtomaturity	13551250000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities Within One Year Amortized Cost MarketableSecuritiesFixedMaturitiesWithinOneYearAmortizedCost	935354000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities Within One Year Fair Value MarketableSecuritiesFixedMaturitiesWithinOneYearFairValue	935894000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After One Through Five Years Amortized Cost MarketableSecuritiesFixedMaturitiesAfterOneThroughFiveYearsAmortizedCost	4666934000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After One Through Five Years Fair Value MarketableSecuritiesFixedMaturitiesAfterOneThroughFiveYearsFairValue	4669502000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After Five Through Ten Years Amortized Cost MarketableSecuritiesFixedMaturitiesAfterFiveThroughTenYearsAmortizedCost	3037450000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After Five Through Ten Years Fair Value MarketableSecuritiesFixedMaturitiesAfterFiveThroughTenYearsFairValue	3045868000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After Ten Years Amortized Cost MarketableSecuritiesFixedMaturitiesAfterTenYearsAmortizedCost	3414764000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities After Ten Years Fair Value MarketableSecuritiesFixedMaturitiesAfterTenYearsFairValue	3361807000	USD
CY2018Q4	wrb	Marketable Securities Debt Maturities Without Single Maturity Date Amortized Cost MarketableSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1620190000	USD
CY2018Q4	wrb	Marketable Securities Debt Maturities Without Single Maturity Date Fair Value MarketableSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1606549000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities Amortized Cost MarketableSecuritiesFixedMaturitiesAmortizedCost	13674692000	USD
CY2018Q4	wrb	Marketable Securities Fixed Maturities Fair Value MarketableSecuritiesFixedMaturitiesFairValue	13619620000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Restricted HeldToMaturitySecuritiesRestricted	1332000000	USD
CY2018Q4	us-gaap	Trading Securities TradingSecurities	453000000	USD
CY2017Q4	us-gaap	Trading Securities TradingSecurities	618000000	USD
CY2018	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	678596000	USD
CY2017	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	582740000	USD
CY2016	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	573323000	USD
CY2018	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	4361000	USD
CY2017	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	6952000	USD
CY2016	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	9160000	USD
CY2018	us-gaap	Net Investment Income NetInvestmentIncome	674235000	USD
CY2017	us-gaap	Net Investment Income NetInvestmentIncome	575788000	USD
CY2016	us-gaap	Net Investment Income NetInvestmentIncome	564163000	USD
CY2018Q4	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	270200000	USD
CY2018Q4	us-gaap	Equity Method Investments EquityMethodInvestments	1332818000	USD
CY2017Q4	us-gaap	Equity Method Investments EquityMethodInvestments	1155677000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	109349000	USD
CY2017	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	68169000	USD
CY2016	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	99301000	USD
CY2018Q4	wrb	Buildingand Lease Obligations BuildingandLeaseObligations	1279584000	USD
CY2017Q4	wrb	Buildingand Lease Obligations BuildingandLeaseObligations	451691000	USD
CY2018Q4	us-gaap	Development In Process DevelopmentInProcess	677508000	USD
CY2017Q4	us-gaap	Development In Process DevelopmentInProcess	1017910000	USD
CY2018Q4	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	1957092000	USD
CY2017Q4	us-gaap	Real Estate Investment Property Net RealEstateInvestmentPropertyNet	1469601000	USD
CY2018Q4	us-gaap	Real Estate Investment Property Accumulated Depreciation RealEstateInvestmentPropertyAccumulatedDepreciation	44340000	USD
CY2017Q4	us-gaap	Real Estate Investment Property Accumulated Depreciation RealEstateInvestmentPropertyAccumulatedDepreciation	25646000	USD
CY2018	us-gaap	Sec Schedule Iii Real Estate Accumulated Depreciation Depreciation Expense SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense	20644000	USD
CY2017	us-gaap	Sec Schedule Iii Real Estate Accumulated Depreciation Depreciation Expense SECScheduleIIIRealEstateAccumulatedDepreciationDepreciationExpense	9212000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable Current OperatingLeasesFutureMinimumPaymentsReceivableCurrent	61458048	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Two Years OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears	62141471	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Three Years OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears	61325176	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Four Years OperatingLeasesFutureMinimumPaymentsReceivableInFourYears	61077419	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable In Five Years OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears	54362011	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Receivable Thereafter OperatingLeasesFutureMinimumPaymentsReceivableThereafter	584592072	USD
CY2018Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	97073000	USD
CY2017Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	82047000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1200000	USD
CY2017Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1200000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	2183000	USD
CY2017Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	2183000	USD
CY2018Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	3383000	USD
CY2017Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	3383000	USD
CY2018	us-gaap	Financing Receivable Allowance For Credit Losses Period Increase Decrease FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease	0	USD
CY2017	us-gaap	Financing Receivable Allowance For Credit Losses Period Increase Decrease FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease	-14000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	1200000	USD
CY2017Q4	us-gaap	Loans And Leases Receivable Impaired Nonperforming Nonaccrual Of Interest LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest	4300000	USD
CY2018	wrb	Availablefor Saleand Heldto Maturity Realized Gains Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedGainsDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	26752000	USD
CY2017	wrb	Availablefor Saleand Heldto Maturity Realized Gains Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedGainsDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	28217000	USD
CY2016	wrb	Availablefor Saleand Heldto Maturity Realized Gains Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedGainsDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	72215000	USD
CY2018	wrb	Availablefor Saleand Heldto Maturity Realized Losses Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedLossesDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	13733000	USD
CY2017	wrb	Availablefor Saleand Heldto Maturity Realized Losses Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedLossesDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	5342000	USD
CY2016	wrb	Availablefor Saleand Heldto Maturity Realized Losses Debt Securities Excluding Otherthan Temporary Impairmentsand Allowances AvailableforSaleandHeldtoMaturityRealizedLossesDebtSecuritiesExcludingOtherthanTemporaryImpairmentsandAllowances	6434000	USD
CY2018	wrb	Equity Securities Fvni Realized Gain EquitySecuritiesFVNIRealizedGain	435150000	USD
CY2017	wrb	Equity Securities Fvni Realized Gain EquitySecuritiesFVNIRealizedGain	154539000	USD
CY2016	wrb	Equity Securities Fvni Realized Gain EquitySecuritiesFVNIRealizedGain	14201000	USD
CY2018	wrb	Equity Securities Fvni Unrealized Gain Loss EquitySecuritiesFVNIUnrealizedGainLoss	-320413000	USD
CY2017	wrb	Equity Securities Fvni Unrealized Gain Loss EquitySecuritiesFVNIUnrealizedGainLoss	0	USD
CY2016	wrb	Equity Securities Fvni Unrealized Gain Loss EquitySecuritiesFVNIUnrealizedGainLoss	0	USD
CY2018	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	-212000	USD
CY2017	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	125423000	USD
CY2016	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	58861000	USD
CY2018	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	27816000	USD
CY2017	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	12880000	USD
CY2016	us-gaap	Gain Loss On Sale Of Properties GainLossOnSaleOfProperties	7757000	USD
CY2018	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	2838000	USD
CY2017	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	0	USD
CY2016	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	0	USD
CY2018	us-gaap	Gain Loss On Sale Of Other Investments GainLossOnSaleOfOtherInvestments	1977000	USD
CY2017	us-gaap	Gain Loss On Sale Of Other Investments GainLossOnSaleOfOtherInvestments	20141000	USD
CY2016	us-gaap	Gain Loss On Sale Of Other Investments GainLossOnSaleOfOtherInvestments	138519000	USD
CY2018	wrb	Realized Gain Losson Investments Including Equity Method Investments Excluding Otherthan Temporary Impairmentsand Allowances RealizedGainLossonInvestmentsIncludingEquityMethodInvestmentsExcludingOtherthanTemporaryImpairmentsandAllowances	160175000	USD
CY2017	wrb	Realized Gain Losson Investments Including Equity Method Investments Excluding Otherthan Temporary Impairmentsand Allowances RealizedGainLossonInvestmentsIncludingEquityMethodInvestmentsExcludingOtherthanTemporaryImpairmentsandAllowances	335858000	USD
CY2016	wrb	Realized Gain Losson Investments Including Equity Method Investments Excluding Otherthan Temporary Impairmentsand Allowances RealizedGainLossonInvestmentsIncludingEquityMethodInvestmentsExcludingOtherthanTemporaryImpairmentsandAllowances	285119000	USD
CY2018	us-gaap	Impairment Of Investments ImpairmentOfInvestments	5687000	USD
CY2017	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2016	us-gaap	Impairment Of Investments ImpairmentOfInvestments	18114000	USD
CY2018	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Before Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsBeforeTax	154488000	USD
CY2017	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Before Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsBeforeTax	335858000	USD
CY2016	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Before Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsBeforeTax	267005000	USD
CY2018	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsTax	32442000	USD
CY2017	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsTax	117550000	USD
CY2016	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsTax	93452000	USD
CY2018	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Netof Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsNetofTax	122046000	USD
CY2017	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Netof Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsNetofTax	218308000	USD
CY2016	wrb	Realized Gain Losson Marketable Securities Equity Method Investmentsand Other Investments Netof Tax RealizedGainLossonMarketableSecuritiesEquityMethodInvestmentsandOtherInvestmentsNetofTax	173553000	USD
CY2018	us-gaap	Available For Sale Securities Change In Net Unrealized Holding Gain Loss AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLoss	-302737000	USD
CY2017	us-gaap	Available For Sale Securities Change In Net Unrealized Holding Gain Loss AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLoss	-69425000	USD
CY2016	us-gaap	Available For Sale Securities Change In Net Unrealized Holding Gain Loss AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLoss	371715000	USD
CY2018	wrb	Changein Unrealized Gainlosson Investmentstax ChangeinUnrealizedGainlossonInvestmentstax	-50410000	USD
CY2017	wrb	Changein Unrealized Gainlosson Investmentstax ChangeinUnrealizedGainlossonInvestmentstax	-17673000	USD
CY2016	wrb	Changein Unrealized Gainlosson Investmentstax ChangeinUnrealizedGainlossonInvestmentstax	125315000	USD
CY2018	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterest	46000	USD
CY2017	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterest	-19000	USD
CY2016	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterest	-59000	USD
CY2018	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest Netof Tax ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterestNetofTax	-252373000	USD
CY2017	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest Netof Tax ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterestNetofTax	-51733000	USD
CY2016	wrb	Changein Unrealized Gainlosson Investments Including Portion Attributableto Noncontrolling Interest Netof Tax ChangeinUnrealizedGainlossonInvestmentsIncludingPortionAttributabletoNoncontrollingInterestNetofTax	246459000	USD
CY2017	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2018Q4	us-gaap	Shortduration Insurance Contracts Liability For Unpaid Claims And Allocated Claim Adjustment Expense Net ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet	10811975000	USD
CY2018Q4	us-gaap	Reinsurance Recoverables On Paid And Unpaid Losses ReinsuranceRecoverablesOnPaidAndUnpaidLosses	1717565000	USD
CY2018Q4	us-gaap	Shortduration Insurance Contracts Discounted Liabilities Aggregate Discount ShortdurationInsuranceContractsDiscountedLiabilitiesAggregateDiscount	563092000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	11966448000	USD
CY2018	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	The table below provides a reconciliation of the beginning and ending reserve balances:<div style="line-height:120%;padding-top:8px;text-align:left;padding-left:0px;text-indent:0px;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:98.78618113912232%;border-collapse:collapse;text-align:left;"><tr><td colspan="12"/></tr><tr><td style="width:56%;"/><td style="width:1%;"/><td style="width:13%;"/><td style="width:1%;"/><td style="width:1%;"/><td style="width:1%;"/><td style="width:11%;"/><td style="width:1%;"/><td style="width:1%;"/><td style="width:1%;"/><td style="width:12%;"/><td style="width:1%;"/></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;font-weight:bold;text-decoration:underline;">(In thousands)</span></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:center;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;font-weight:bold;">2018</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:center;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;font-weight:bold;">2017</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:center;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;font-weight:bold;">2016</span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Net reserves at beginning of year</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>10,056,914</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>9,590,265</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>9,244,872</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Net provision for losses and loss expenses:</span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Claims occurring during the current year (1)</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,926,489</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,963,543</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,826,620</span></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Increase (decrease) in estimates for claims occurring in prior years (2)</span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>6,831</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>(5,165</span></span></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">)</span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>(29,904</span></span></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Loss reserve discount accretion</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>41,382</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>43,970</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>49,084</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:20px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Total</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,974,702</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>4,002,348</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,845,800</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Net payments for claims:</span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"> </span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"> </span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"> </span></div></td><td style="vertical-align:bottom;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Current year</span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>964,808</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>1,027,405</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>1,052,452</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:12px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Prior year</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>2,700,077</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>2,562,550</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>2,401,722</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:20px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Total</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,664,885</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,589,955</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>3,454,174</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Foreign currency translation</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>(117,848</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">)</span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>54,256</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;border-top:1px solid #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>(46,233</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">)</span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Net reserves at end of year</span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>10,248,883</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>10,056,914</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>9,590,265</span></span></div></td><td style="vertical-align:bottom;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Ceded reserve at end of year</span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>1,717,565</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>1,613,494</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>1,606,930</span></span></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Gross reserves at end of year</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>11,966,448</span></span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>11,670,408</span></span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;"><div style="overflow:hidden;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;"><div style="text-align:left;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;">$</span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;padding-top:2px;padding-bottom:2px;"><div style="text-align:right;font-size:9pt;"><span style="font-family:inherit;font-size:9pt;"><span>11,197,195</span></span></div></td><td style="vertical-align:bottom;border-bottom:3px double #000000;"><div style="text-align:left;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"><br/></span></div></td></tr></table></div><span style="font-family:inherit;font-size:10pt;"><br/></span></div><div style="line-height:120%;font-size:8pt;"><span style="font-family:inherit;font-size:8pt;">_______________________________________</span></div><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;"/><td/></tr><tr><td style="vertical-align:top"><div style="line-height:120%;vertical-align:bottom;font-size:10pt;padding-left:0px;"><span style="font-family:inherit;font-size:10pt;">(1)</span></div></td><td style="vertical-align:top;"><div style="line-height:120%;vertical-align:bottom;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Claims occurring during the current year are net of loss reserve discounts of </span><span style="font-family:inherit;font-size:10pt;"><span>$24,381,000</span></span><span style="font-family:inherit;font-size:10pt;">, </span><span style="font-family:inherit;font-size:10pt;"><span>$22,064,000</span></span><span style="font-family:inherit;font-size:10pt;"> and </span><span style="font-family:inherit;font-size:10pt;"><span>$18,929,000</span></span><span style="font-family:inherit;font-size:10pt;"> in </span><span style="font-family:inherit;font-size:10pt;">2018</span><span style="font-family:inherit;font-size:10pt;">, </span><span style="font-family:inherit;font-size:10pt;">2017</span><span style="font-family:inherit;font-size:10pt;">, and </span><span style="font-family:inherit;font-size:10pt;">2016</span><span style="font-family:inherit;font-size:10pt;">, respectively.</span></div></td></tr></table><div style="line-height:120%;vertical-align:bottom;font-size:10pt;padding-left:0px;"><span style="font-family:inherit;font-size:10pt;">(2)</span></div><span style="font-family:inherit;font-size:10pt;">The increase (decrease) in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years decreased by </span><span style="font-family:inherit;font-size:10pt;"><span>$3,738,000</span></span><span style="font-family:inherit;font-size:10pt;">, </span><span style="font-family:inherit;font-size:10pt;"><span>$32,132,000</span></span><span style="font-family:inherit;font-size:10pt;"> and </span><span style="font-family:inherit;font-size:10pt;"><span>$59,175,000</span></span><span style="font-family:inherit;font-size:10pt;"> in </span><span style="font-family:inherit;font-size:10pt;">2018</span><span style="font-family:inherit;font-size:10pt;">, </span><span style="font-family:inherit;font-size:10pt;">2017</span><span style="font-family:inherit;font-size:10pt;"> and </span><span style="font-family:inherit;font-size:10pt;">2016</span>, respectively.
CY2017Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10056914000	USD
CY2016Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	9590265000	USD
CY2015Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	9244872000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3926489000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3963543000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3826620000	USD
CY2018	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Incurred Claims Adjustment LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseIncurredClaimsAdjustment	-6831000	USD
CY2017	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Loss Reserve Discount Accretion LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredLossReserveDiscountAccretion	-43970000	USD
CY2016	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Loss Reserve Discount Accretion LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredLossReserveDiscountAccretion	-49084000	USD
CY2017	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Incurred Claims Adjustment LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseIncurredClaimsAdjustment	5165000	USD
CY2016	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Incurred Claims Adjustment LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseIncurredClaimsAdjustment	29904000	USD
CY2018	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Loss Reserve Discount Accretion LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredLossReserveDiscountAccretion	-41382000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3974702000	USD
CY2017	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	4002348000	USD
CY2016	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	3845800000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	964808000	USD
CY2017	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1027405000	USD
CY2016	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1052452000	USD
CY2018	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	2700077000	USD
CY2017	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	2562550000	USD
CY2016	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	2401722000	USD
CY2018	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	3664885000	USD
CY2017	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	3589955000	USD
CY2016	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	3454174000	USD
CY2018	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Foreign Exchange Translation LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseForeignExchangeTranslation	-117848000	USD
CY2017	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Foreign Exchange Translation LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseForeignExchangeTranslation	54256000	USD
CY2016	wrb	Liabilityfor Unpaid Claimsand Claims Adjustment Expense Foreign Exchange Translation LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseForeignExchangeTranslation	-46233000	USD
CY2018Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10248883000	USD
CY2017Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	10056914000	USD
CY2016Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	9590265000	USD
CY2018Q4	us-gaap	Reinsurance Recoverables Gross ReinsuranceRecoverablesGross	1717565000	USD
CY2017Q4	us-gaap	Reinsurance Recoverables Gross ReinsuranceRecoverablesGross	1613494000	USD
CY2016Q4	us-gaap	Reinsurance Recoverables Gross ReinsuranceRecoverablesGross	1606930000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	11966448000	USD
CY2017Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	11670408000	USD
CY2016Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	11197195000	USD
CY2018Q4	us-gaap	Workers Compensation Discount Amount WorkersCompensationDiscountAmount	24381000	USD
CY2017Q4	us-gaap	Workers Compensation Discount Amount WorkersCompensationDiscountAmount	22064000	USD
CY2016Q4	us-gaap	Workers Compensation Discount Amount WorkersCompensationDiscountAmount	18929000	USD
CY2018	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims Undiscounted Basis Prior Years Increase Decrease LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsUndiscountedBasisPriorYearsIncreaseDecrease	3738000	USD
CY2017	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims Undiscounted Basis Prior Years Increase Decrease LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsUndiscountedBasisPriorYearsIncreaseDecrease	32132000	USD
CY2016	wrb	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims Undiscounted Basis Prior Years Increase Decrease LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsUndiscountedBasisPriorYearsIncreaseDecrease	59175000	USD
CY2018	wrb	Favorable Reserve Development Net Of Premium Offsets FavorableReserveDevelopmentNetOfPremiumOffsets	39000000	USD
CY2017	wrb	Favorable Reserve Development Net Of Premium Offsets FavorableReserveDevelopmentNetOfPremiumOffsets	37000000	USD
CY2016	wrb	Favorable Reserve Development Net Of Premium Offsets FavorableReserveDevelopmentNetOfPremiumOffsets	59000000	USD
CY2018Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	28000000	USD
CY2017Q4	us-gaap	Liability For Asbestos And Environmental Claims Net LiabilityForAsbestosAndEnvironmentalClaimsNet	30000000	USD
CY2017Q4	us-gaap	Workers Compensation Discount Prior Year Amount WorkersCompensationDiscountPriorYearAmount	1855000000	USD
CY2018Q4	wrb	Workers Compensation Discount After Effects Of Ceded Reinsurance Amount WorkersCompensationDiscountAfterEffectsOfCededReinsuranceAmount	563000000	USD
CY2017Q4	wrb	Workers Compensation Discount After Effects Of Ceded Reinsurance Amount WorkersCompensationDiscountAfterEffectsOfCededReinsuranceAmount	591000000	USD
CY2018	us-gaap	Direct Premiums Written DirectPremiumsWritten	6973216000	USD
CY2017	us-gaap	Direct Premiums Written DirectPremiumsWritten	6726029000	USD
CY2016	us-gaap	Direct Premiums Written DirectPremiumsWritten	6647600000	USD
CY2018	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	729278000	USD
CY2017	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	750934000	USD
CY2016	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	896101000	USD
CY2018	us-gaap	Ceded Premiums Written CededPremiumsWritten	1269267000	USD
CY2017	us-gaap	Ceded Premiums Written CededPremiumsWritten	1216455000	USD
CY2016	us-gaap	Ceded Premiums Written CededPremiumsWritten	1119788000	USD
CY2018	us-gaap	Premiums Written Net PremiumsWrittenNet	6433227000	USD
CY2017	us-gaap	Premiums Written Net PremiumsWrittenNet	6260508000	USD
CY2016	us-gaap	Premiums Written Net PremiumsWrittenNet	6423913000	USD
CY2018	us-gaap	Direct Premiums Earned DirectPremiumsEarned	6851795000	USD
CY2017	us-gaap	Direct Premiums Earned DirectPremiumsEarned	6661046000	USD
CY2016	us-gaap	Direct Premiums Earned DirectPremiumsEarned	6492240000	USD
CY2018	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	755759000	USD
CY2017	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	812309000	USD
CY2016	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	900570000	USD
CY2018	us-gaap	Ceded Premiums Earned CededPremiumsEarned	1236049000	USD
CY2017	us-gaap	Ceded Premiums Earned CededPremiumsEarned	1161936000	USD
CY2016	us-gaap	Ceded Premiums Earned CededPremiumsEarned	1099462000	USD
CY2018	us-gaap	Premiums Earned Net PremiumsEarnedNet	6371505000	USD
CY2017	us-gaap	Premiums Earned Net PremiumsEarnedNet	6311419000	USD
CY2016	us-gaap	Premiums Earned Net PremiumsEarnedNet	6293348000	USD
CY2018	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	829742000	USD
CY2017	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	601769000	USD
CY2016	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	707336000	USD
CY2018	us-gaap	Fees And Commissions Other FeesAndCommissionsOther	268037000	USD
CY2017	us-gaap	Fees And Commissions Other FeesAndCommissionsOther	241983000	USD
CY2016	us-gaap	Fees And Commissions Other FeesAndCommissionsOther	201957000	USD
CY2018Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	946965	USD
CY2017Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1010000	USD
CY2016Q4	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	1049000	USD
CY2018Q4	us-gaap	Reinsurance Recoverables ReinsuranceRecoverables	1932291000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	188712000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-63134000	USD
CY2018	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	125578000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	13963000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	23487000	USD
CY2018	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	37450000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	202675000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-39647000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	163028000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	225694000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-27601000	USD
CY2017	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	198093000	USD
CY2017	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	8803000	USD
CY2017	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	12537000	USD
CY2017	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	21340000	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	234497000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-15064000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	219433000	USD
CY2016	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	259539000	USD
CY2016	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	3355000	USD
CY2016	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	262894000	USD
CY2016	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	23634000	USD
CY2016	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	6425000	USD
CY2016	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	30059000	USD
CY2016	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	283173000	USD
CY2016	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	9780000	USD
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	292953000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	755000000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	797000000	USD
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	837000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	57000000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-25000000	USD
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	59000000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	170540000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	270470000	USD
CY2016	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	313753000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	18833000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	37209000	USD
CY2016	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	37379000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	18576000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	11161000	USD
CY2016	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	1420000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	7683000	USD
CY2017	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	3508000	USD
CY2016	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	1984000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	3901000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	1644000	USD
CY2016	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	7748000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-10950000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-30531000	USD
CY2016	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-7889000	USD
CY2017	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	390000	USD
CY2016	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	5427000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	163028000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	219433000	USD
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	292953000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	130513000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	70206000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	112190000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Unearned Premiums Reserve DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve	110854000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	37463000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	33043000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Impairment Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses	9910000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Impairment Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses	8204000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	56027000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	59037000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	58809000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	49346000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	404912000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	330690000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	35195000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	16619000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	369717000	USD
CY2017Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	314071000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	13641000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	12826000	USD
CY2018Q4	wrb	Tax Cutsand Jobs Act Incomplete Accounting Deferred Tax Liabilities Provisional Undistributed Foreign Earnings TaxCutsandJobsActIncompleteAccountingDeferredTaxLiabilitiesProvisionalUndistributedForeignEarnings	41088000	USD
CY2017Q4	wrb	Tax Cutsand Jobs Act Incomplete Accounting Deferred Tax Liabilities Provisional Undistributed Foreign Earnings TaxCutsandJobsActIncompleteAccountingDeferredTaxLiabilitiesProvisionalUndistributedForeignEarnings	0	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	99293000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Policy Acquisition Cost DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost	100020000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Unrealized Gains On Trading Securities DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities	35430000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Unrealized Gains On Trading Securities DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities	151162000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	39239000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	31865000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	51712000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	41104000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	53824000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	63858000	USD
CY2018Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	334227000	USD
CY2017Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	400835000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	35490000	USD
CY2017Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	86764000	USD
CY2018Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	700000	USD
CY2017Q4	us-gaap	Taxes Payable Current And Noncurrent TaxesPayableCurrentAndNoncurrent	11300000	USD
CY2018Q4	us-gaap	Tax Credit Carryforward Valuation Allowance TaxCreditCarryforwardValuationAllowance	35200000	USD
CY2017Q4	us-gaap	Tax Credit Carryforward Valuation Allowance TaxCreditCarryforwardValuationAllowance	16600000	USD
CY2018	wrb	Tax Cutsand Jobs Act Income Tax Expense Benefit TaxCutsandJobsActIncomeTaxExpenseBenefit	-11000000.0	USD
CY2018Q1	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Loss Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves	47000000	USD
CY2018	wrb	Tax Cutsand Jobs Act Income Tax Expense Benefit Gilti TaxCutsandJobsActIncomeTaxExpenseBenefitGILTI	2800000	USD
CY2018Q4	us-gaap	Undistributed Earnings Of Foreign Subsidiaries UndistributedEarningsOfForeignSubsidiaries	70000000	USD
CY2018Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments Without Regulatory Approval StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval	1100000000	USD
CY2018	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	1099953000	USD
CY2017	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	698862000	USD
CY2016	us-gaap	Statutory Accounting Practices Statutory Net Income Amount StatutoryAccountingPracticesStatutoryNetIncomeAmount	702830000	USD
CY2018Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	5587930000	USD
CY2017Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	5479603000	USD
CY2016Q4	us-gaap	Statutory Accounting Practices Statutory Capital And Surplus Balance StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance	5493044000	USD
CY2018Q4	wrb	Statutory Accounting Practices Statutory Capitaland Surplus Total Increase Decrease Effecton Balance StatutoryAccountingPracticesStatutoryCapitalandSurplusTotalIncreaseDecreaseEffectonBalance	282000000	USD
CY2018Q4	wrb	Statutory Accounting Practices Statutory Capitaland Surplus Adjusted Capital Balance Remedial Threshold Percent StatutoryAccountingPracticesStatutoryCapitalandSurplusAdjustedCapitalBalanceRemedialThresholdPercent	2
CY2018Q4	wrb	Statutory Accounting Practices Statutory Capitaland Surplus Adjusted Capital Balance StatutoryAccountingPracticesStatutoryCapitalandSurplusAdjustedCapitalBalance	5306000000	USD
CY2018Q4	wrb	Statutory Accounting Practices Statutory Capitaland Surplus Adjusted Capital Balance Percent StatutoryAccountingPracticesStatutoryCapitalandSurplusAdjustedCapitalBalancePercent	3.84
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	126698927	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	124843240	shares
CY2016	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	122650997	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	128263558	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	129017613	shares
CY2016	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	128552838	shares
CY2017Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	121514852	shares
CY2017	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1111489000	USD
CY2016	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1155954000	USD
CY2016Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	121193599	shares
CY2015Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	123307837	shares
CY2018	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	838508	shares
CY2017	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	1052256	shares
CY2016	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	281654	shares
CY2018	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	357600	shares
CY2017	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	731003	shares
CY2016	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2395892	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	121995760	shares
CY2017Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	121514852	shares
CY2016Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	121193599	shares
CY2018Q4	wrb	Due To Broker DueToBroker	20144000	USD
CY2018Q4	wrb	Due To Broker Fair Value DueToBrokerFairValue	20144000	USD
CY2017Q4	wrb	Due To Broker DueToBroker	15920000	USD
CY2017Q4	wrb	Due To Broker Fair Value DueToBrokerFairValue	15920000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	46592000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	43504000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	39061000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	34444000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	30881000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	75740000	USD
CY2018	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	45778000	USD
CY2017	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	52925000	USD
CY2016	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	47453000	USD
CY2018	wrb	Commitmentto Investin Certain Investment Funds CommitmenttoInvestinCertainInvestmentFunds	270200000	USD
CY2018	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	1183635000	USD
CY2017	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	989535000	USD
CY2016	us-gaap	Other Underwriting Expense OtherUnderwritingExpense	933249000	USD
CY2018	wrb	Service Company Expenses ServiceCompanyExpenses	118357000	USD
CY2018	wrb	Commitmentto Investin Real Estate Construction Projects CommitmenttoInvestinRealEstateConstructionProjects	253400000	USD
CY2018	us-gaap	Deferred Compensation Arrangement With Individual Shares Issued DeferredCompensationArrangementWithIndividualSharesIssued	4709318	shares
CY2018	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	21438000	USD
CY2017	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	21264000	USD
CY2016	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	20413000	USD
CY2018	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	915246000	USD
CY2017	wrb	Service Company Expenses ServiceCompanyExpenses	129776000	USD
CY2016	wrb	Service Company Expenses ServiceCompanyExpenses	138908000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	27067000	USD
CY2017	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-15267000	USD
CY2016	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	11904000	USD
CY2018	wrb	Other Costs And Expense Operating Other OtherCostsAndExpenseOperatingOther	193050000	USD
CY2017	wrb	Other Costs And Expense Operating Other OtherCostsAndExpenseOperatingOther	190865000	USD
CY2016	wrb	Other Costs And Expense Operating Other OtherCostsAndExpenseOperatingOther	179412000	USD
CY2018	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	2383221000	USD
CY2017	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	2436932000	USD
CY2016	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	2395619000	USD
CY2018	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2018	us-gaap	Gain Loss On Investments GainLossOnInvestments	154488000	USD
CY2018	us-gaap	Gain Loss On Investments GainLossOnInvestments	154488000	USD
CY2018	us-gaap	Gain Loss On Investments GainLossOnInvestments	154488000	USD
CY2018	us-gaap	Income Loss From Subsidiaries Net Of Tax IncomeLossFromSubsidiariesNetOfTax	122046000	USD
CY2018	us-gaap	Premiums Earned Net PremiumsEarnedNet	6371505000	USD
CY2018	us-gaap	Net Investment Income NetInvestmentIncome	674235000	USD
CY2018	wrb	Other Revenues OtherRevenues	645911000	USD
CY2018	us-gaap	Revenues Revenues	7691651000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	812094000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	640749000	USD
CY2017	us-gaap	Gain Loss On Investments GainLossOnInvestments	335858000	USD
CY2017	us-gaap	Gain Loss On Investments GainLossOnInvestments	335858000	USD
CY2017	us-gaap	Gain Loss On Investments GainLossOnInvestments	335858000	USD
CY2017	us-gaap	Income Loss From Subsidiaries Net Of Tax IncomeLossFromSubsidiariesNetOfTax	218308000	USD
CY2017	us-gaap	Premiums Earned Net PremiumsEarnedNet	6311419000	USD
CY2017	us-gaap	Net Investment Income NetInvestmentIncome	575788000	USD
CY2017	wrb	Other Revenues OtherRevenues	797557000	USD
CY2017	us-gaap	Revenues Revenues	7684764000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	772770000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	549094000	USD
CY2016	us-gaap	Gain Loss On Investments GainLossOnInvestments	267005000	USD
CY2016	us-gaap	Gain Loss On Investments GainLossOnInvestments	267005000	USD
CY2016	us-gaap	Gain Loss On Investments GainLossOnInvestments	267005000	USD
CY2016	us-gaap	Income Loss From Subsidiaries Net Of Tax IncomeLossFromSubsidiariesNetOfTax	173553000	USD
CY2016	us-gaap	Premiums Earned Net PremiumsEarnedNet	6293348000	USD
CY2016	us-gaap	Net Investment Income NetInvestmentIncome	564163000	USD
CY2016	wrb	Other Revenues OtherRevenues	796673000	USD
CY2016	us-gaap	Revenues Revenues	7654184000	USD
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	896438000	USD
CY2016	us-gaap	Net Income Loss NetIncomeLoss	601916000	USD
CY2018Q4	us-gaap	Assets Assets	24895977000	USD
CY2017Q4	us-gaap	Assets Assets	24299917000	USD
CY2018	us-gaap	Premiums Earned Net PremiumsEarnedNet	6371505000	USD
CY2017	us-gaap	Premiums Earned Net PremiumsEarnedNet	6311419000	USD
CY2016	us-gaap	Premiums Earned Net PremiumsEarnedNet	6293348000	USD
CY2018Q1	us-gaap	Revenues Revenues	1891247000	USD
CY2018Q2	us-gaap	Revenues Revenues	1910916000	USD
CY2018Q3	us-gaap	Revenues Revenues	1937902000	USD
CY2018Q4	us-gaap	Revenues Revenues	1951586000	USD
CY2018Q1	us-gaap	Net Income Loss NetIncomeLoss	166397000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	180075000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	161920000	USD
CY2018Q4	us-gaap	Net Income Loss NetIncomeLoss	132357000	USD
CY2018Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.42
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.28
CY2018Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.04
CY2018Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.30
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.40
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.26
CY2018Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.03
CY2017Q1	us-gaap	Revenues Revenues	1870418000	USD
CY2016	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	6293348000	USD
CY2016	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	564163000	USD
CY2016	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	3845800000	USD
CY2017Q2	us-gaap	Revenues Revenues	1848049000	USD
CY2017Q3	us-gaap	Revenues Revenues	2031342000	USD
CY2017Q4	us-gaap	Revenues Revenues	1934956000	USD
CY2017Q1	us-gaap	Net Income Loss NetIncomeLoss	123447000	USD
CY2017Q2	us-gaap	Net Income Loss NetIncomeLoss	109004000	USD
CY2017Q3	us-gaap	Net Income Loss NetIncomeLoss	162054000	USD
CY2017Q4	us-gaap	Net Income Loss NetIncomeLoss	154589000	USD
CY2017Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.01
CY2017Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.87
CY2017Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.29
CY2017Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.22
CY2017Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.96
CY2017Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.85
CY2017Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.26
CY2017Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.21
CY2018Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	497629000	USD
CY2018Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	11966448000	USD
CY2018Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	3359991000	USD
CY2018	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	6371505000	USD
CY2018	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	674235000	USD
CY2018	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	3974702000	USD
CY2018	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	915246000	USD
CY2018	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1467975000	USD
CY2018	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	6433227000	USD
CY2017Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	507549000	USD
CY2017Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	11670408000	USD
CY2017Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	3290180000	USD
CY2017	us-gaap	Supplementary Insurance Information Premium Revenue SupplementaryInsuranceInformationPremiumRevenue	6311419000	USD
CY2017	us-gaap	Supplementary Insurance Information Net Investment Income SupplementaryInsuranceInformationNetInvestmentIncome	575788000	USD
CY2017	us-gaap	Supplementary Insurance Information Benefits Claims Losses And Settlement Expense SupplementaryInsuranceInformationBenefitsClaimsLossesAndSettlementExpense	4002348000	USD
CY2017	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	1111489000	USD
CY2017	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1325443000	USD
CY2017	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	6260508000	USD
CY2016Q4	us-gaap	Supplementary Insurance Information Deferred Policy Acquisition Costs SupplementaryInsuranceInformationDeferredPolicyAcquisitionCosts	537890000	USD
CY2016Q4	us-gaap	Supplementary Insurance Information Liability For Future Policy Benefits Losses Claims And Loss Expense Reserves SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves	11197195000	USD
CY2016Q4	us-gaap	Supplementary Insurance Information Unearned Premiums SupplementaryInsuranceInformationUnearnedPremiums	3283300000	USD
CY2016	us-gaap	Supplementary Insurance Information Amortization Of Deferred Policy Acquisition Costs SupplementaryInsuranceInformationAmortizationOfDeferredPolicyAcquisitionCosts	1155954000	USD
CY2016	us-gaap	Supplementary Insurance Information Other Operating Expense SupplementaryInsuranceInformationOtherOperatingExpense	1239665000	USD
CY2016	us-gaap	Supplementary Insurance Information Premiums Written SupplementaryInsuranceInformationPremiumsWritten	6423913000	USD
CY2018	us-gaap	Direct Premiums Written DirectPremiumsWritten	6973216000	USD
CY2018	us-gaap	Ceded Premiums Written CededPremiumsWritten	1269267000	USD
CY2018	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	729278000	USD
CY2018	us-gaap	Premiums Written Net PremiumsWrittenNet	6433227000	USD
CY2018	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.113
CY2017	us-gaap	Direct Premiums Written DirectPremiumsWritten	6726029000	USD
CY2017	us-gaap	Ceded Premiums Written CededPremiumsWritten	1216455000	USD
CY2017	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	750934000	USD
CY2017	us-gaap	Premiums Written Net PremiumsWrittenNet	6260508000	USD
CY2017	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.120
CY2016	us-gaap	Direct Premiums Written DirectPremiumsWritten	6647600000	USD
CY2016	us-gaap	Ceded Premiums Written CededPremiumsWritten	1119788000	USD
CY2016	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	896101000	USD
CY2016	us-gaap	Premiums Written Net PremiumsWrittenNet	6423913000	USD
CY2016	us-gaap	Premiums Percentage Assumed To Net PremiumsPercentageAssumedToNet	0.139
CY2018Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts	497629000	USD
CY2017Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts	507549000	USD
CY2016Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts	537890000	USD
CY2018Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Reserves For Unpaid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense	11966448000	USD
CY2017Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Reserves For Unpaid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense	11670408000	USD
CY2016Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Reserves For Unpaid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense	11197195000	USD
CY2018Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Unearned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums	3359991000	USD
CY2017Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Unearned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums	3290180000	USD
CY2016Q4	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Unearned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums	3283300000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Earned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums	6371505000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Earned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums	6311419000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Earned Premiums SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums	6293348000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Net Investment Income SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome	674235000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Net Investment Income SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome	575788000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Net Investment Income SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome	564163000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3926489000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3963543000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	3826620000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	6831000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-5165000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-29904000	USD
CY2018	wrb	Supplemental Informationfor Property Casualty Insurance Underwriters Loss Reserve Discount Accretion SupplementalInformationforPropertyCasualtyInsuranceUnderwritersLossReserveDiscountAccretion	41382000	USD
CY2017	wrb	Supplemental Informationfor Property Casualty Insurance Underwriters Loss Reserve Discount Accretion SupplementalInformationforPropertyCasualtyInsuranceUnderwritersLossReserveDiscountAccretion	43970000	USD
CY2016	wrb	Supplemental Informationfor Property Casualty Insurance Underwriters Loss Reserve Discount Accretion SupplementalInformationforPropertyCasualtyInsuranceUnderwritersLossReserveDiscountAccretion	49084000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Amortization Of Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts	915246000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Amortization Of Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts	1111489000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Amortization Of Deferred Policy Acquisition Costs SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts	1155954000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Paid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense	3664885000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Paid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense	3589955000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Paid Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense	3454174000	USD
CY2018	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Premiums Written SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten	6433227000	USD
CY2017	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Premiums Written SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten	6260508000	USD
CY2016	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Premiums Written SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten	6423913000	USD

Files In Submission

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0000011544-19-000016-index.html	Edgar Link	pending
0000011544-19-000016.txt	Edgar Link	pending
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report.css	Edgar Link	pending
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wrb-20181231.xsd	Edgar Link	pending
wrb-20181231_cal.xml	Edgar Link	unprocessable
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wrb-20181231_lab.xml	Edgar Link	unprocessable
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wrb1231201810-k.htm	Edgar Link	pending
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wrb1231201810-kex312.htm	Edgar Link	pending
wrb1231201810-kex321.htm	Edgar Link	pending
wrb1231201810-k_htm.xml	Edgar Link	completed

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$WRB
BERKLEY W R CORP Stock $wrb

2017 Q4 Form 10-K Financial Statement

#000001154419000016 Filed on February 22, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WRB BERKLEY W R CORP Stock $wrb

2017 Q4 Form 10-K Financial Statement

#000001154419000016 Filed on February 22, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WRB
BERKLEY W R CORP Stock $wrb