$SBSI
SOUTHSIDE BANCSHARES INC Stock $sbsi

$sbsi Overview Financials Valuation SEC Filings Company Website

2024 Q4 Form 10-Q Financial Statement

#000070543224000225 Filed on October 28, 2024

Income Statement

Concept	2024 Q4	2024 Q3
Revenue		$105.7M
YoY Change		13.56%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization		$2.556M
YoY Change		-5.33%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense
YoY Change
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income		$24.91M
YoY Change		15.51%
Income Tax		$4.390M
% Of Pretax Income		17.62%
Net Earnings		$20.52M
YoY Change		11.25%
Net Earnings / Revenue		19.42%
Basic Earnings Per Share		$0.68
Diluted Earnings Per Share		$0.68
COMMON SHARES
Basic Shares Outstanding	30.31M shares	30.27M shares
Diluted Shares Outstanding		30.37M shares

Balance Sheet

Concept	2024 Q4	2024 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents		$486.3M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment		$138.8M
YoY Change		-0.47%
Goodwill		$201.1M
YoY Change		0.0%
Intangibles		$2.003M
YoY Change		-39.21%
Long-Term Investments		$9.722M
YoY Change		2.34%
Other Assets		$32.64M
YoY Change		-20.77%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets		$8.362B
YoY Change		4.89%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses		$15.92M
YoY Change		-5.24%
Deferred Revenue
YoY Change
Short-Term Debt		$105.8M
YoY Change		-73.23%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities		$121.7M
YoY Change		-70.45%
LONG-TERM LIABILITIES
Long-Term Debt		$152.3M
YoY Change		-1.18%
Other Long-Term Liabilities		$103.2M
YoY Change		-10.6%
Total Long-Term Liabilities		$255.5M
YoY Change		-5.21%
TOTAL LIABILITIES
Total Short-Term Liabilities		$121.7M
Total Long-Term Liabilities		$255.5M
Total Liabilities		$7.557B
YoY Change		4.32%
SHAREHOLDERS EQUITY
Retained Earnings		$316.1M
YoY Change		14.38%
Common Stock		$839.8M
YoY Change		0.49%
Preferred Stock
YoY Change
Treasury Stock (at cost)		$232.1M
YoY Change		1.61%
Treasury Stock Shares
Shareholders Equity		$805.3M
YoY Change
Total Liabilities & Shareholders Equity		$8.362B
YoY Change		4.89%

Cashflow Statement

Concept	2024 Q4	2024 Q3
OPERATING ACTIVITIES
Net Income		$20.52M
YoY Change		11.25%
Depreciation, Depletion And Amortization		$2.556M
YoY Change		-5.33%
Cash From Operating Activities		-$11.74M
YoY Change		-114.95%
INVESTING ACTIVITIES
Capital Expenditures		$2.423M
YoY Change		27.53%
Acquisitions
YoY Change
Other Investing Activities		$16.23M
YoY Change		-116.51%
Cash From Investing Activities		$13.81M
YoY Change		-113.78%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities		32.23M
YoY Change		-77.06%
NET CHANGE
Cash From Operating Activities		-11.74M
Cash From Investing Activities		13.81M
Cash From Financing Activities		32.23M
Net Change In Cash		34.30M
YoY Change		-71.13%
FREE CASH FLOW
Cash From Operating Activities		-$11.74M
Capital Expenditures		$2.423M
Free Cash Flow		-$14.16M
YoY Change		-118.48%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0000705432
	dei	Document Period End Date DocumentPeriodEndDate	2024-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity Registrant Name EntityRegistrantName	SOUTHSIDE BANCSHARES, INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	TX
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	75-1848732
	dei	Entity Address Address Line1 EntityAddressAddressLine1	1201 S. Beckham Avenue,
	dei	Entity Address City Or Town EntityAddressCityOrTown	Tyler,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	TX
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	75701
	dei	City Area Code CityAreaCode	903
	dei	Security12b Title Security12bTitle	Common Stock, $1.25 par value
	dei	Trading Symbol TradingSymbol	SBSI
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
CY2024Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	30308414	shares
CY2024Q3	us-gaap	Cash And Due From Banks CashAndDueFromBanks	130147000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1332467000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1408437000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1296294000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1169523000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1166162000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1288403000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1307053000	usd
CY2024Q3	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	40291000	usd
CY2024Q3	us-gaap	Interest Receivable InterestReceivable	37888000	usd
CY2023Q4	us-gaap	Interest Receivable InterestReceivable	50489000	usd
CY2023Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	30426000	usd
CY2024Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	15919000	usd
CY2024Q3	us-gaap	Common Stock Value CommonStockValue	47588000	usd
CY2023Q4	us-gaap	Common Stock Value CommonStockValue	47550000	usd
CY2024Q3	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	792249000	usd
CY2023Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	788840000	usd
CY2024Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	316050000	usd
CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	282355000	usd
CY2024Q3	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	7762336	shares
CY2023Q4	us-gaap	Treasury Stock Common Shares TreasuryStockCommonShares	7790276	shares
CY2024Q3	us-gaap	Treasury Stock Value TreasuryStockValue	232134000	usd
CY2023Q4	us-gaap	Treasury Stock Value TreasuryStockValue	231995000	usd
CY2024Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-118499000	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-113462000	usd
CY2024Q3	us-gaap	Stockholders Equity StockholdersEquity	805254000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	773288000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	8284914000	usd
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	177570000	usd
CY2024Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	7150000	usd
CY2023Q3	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	8731000	usd
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	21126000	usd
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	23216000	usd
CY2024Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	9813000	usd
CY2023Q3	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	13758000	usd
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	31611000	usd
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	41394000	usd
CY2024Q3	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	11976000	usd
CY2023Q3	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	4426000	usd
	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	33179000	usd
CY2023Q3	us-gaap	Interest Income Other InterestIncomeOther	1788000	usd
	us-gaap	Interest Income Other InterestIncomeOther	15452000	usd
	us-gaap	Interest Income Other InterestIncomeOther	5148000	usd
CY2024Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	105703000	usd
CY2023Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	93078000	usd
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	312647000	usd
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	260802000	usd
CY2024Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	38532000	usd
CY2023Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	30951000	usd
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	115196000	usd
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	72536000	usd
CY2024Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Short Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm	6488000	usd
CY2023Q3	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Short Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm	1174000	usd
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Short Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm	18893000	usd
	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Short Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm	5347000	usd
CY2024Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	937000	usd
CY2023Q3	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	962000	usd
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	2829000	usd
	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	2955000	usd
CY2024Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	1180000	usd
CY2023Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	1178000	usd
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	3526000	usd
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	3309000	usd
CY2024Q3	us-gaap	Interest Expense Other InterestExpenseOther	3102000	usd
	us-gaap	Interest Expense Other InterestExpenseOther	9783000	usd
	us-gaap	Interest Expense Other InterestExpenseOther	16113000	usd
CY2024Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	55464000	usd
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	160542000	usd
CY2024Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	2389000	usd
CY2023Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6987000	usd
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	1962000	usd
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6873000	usd
CY2024Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	53075000	usd
CY2023Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	46286000	usd
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	160458000	usd
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	153669000	usd
CY2024Q3	sbsi	Fee And Commissions Depositor Account FeeAndCommissionsDepositorAccount	6199000	usd
CY2023Q3	sbsi	Fee And Commissions Depositor Account FeeAndCommissionsDepositorAccount	6479000	usd
	sbsi	Fee And Commissions Depositor Account FeeAndCommissionsDepositorAccount	18341000	usd
	sbsi	Fee And Commissions Depositor Account FeeAndCommissionsDepositorAccount	19192000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-1929000	usd
CY2023Q3	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	11000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-2510000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-5590000	usd
CY2024Q3	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
CY2023Q3	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	5058000	usd
CY2023Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1178000	usd
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2731000	usd
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	4227000	usd
CY2024Q3	us-gaap	Noninterest Income NoninterestIncome	8171000	usd
CY2023Q3	us-gaap	Noninterest Income NoninterestIncome	10836000	usd
	us-gaap	Noninterest Income NoninterestIncome	29452000	usd
	us-gaap	Noninterest Income NoninterestIncome	33333000	usd
CY2024Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	22233000	usd
CY2023Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	21241000	usd
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	67330000	usd
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	64473000	usd
CY2024Q3	us-gaap	Occupancy Net OccupancyNet	3613000	usd
CY2023Q3	us-gaap	Occupancy Net OccupancyNet	3796000	usd
	us-gaap	Occupancy Net OccupancyNet	10725000	usd
	us-gaap	Occupancy Net OccupancyNet	11220000	usd
CY2024Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	734000	usd
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	2479000	usd
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	2966000	usd
CY2024Q3	sbsi	Atm Expense ATMExpense	412000	usd
CY2023Q3	sbsi	Atm Expense ATMExpense	358000	usd
	sbsi	Atm Expense ATMExpense	1105000	usd
	sbsi	Atm Expense ATMExpense	1033000	usd
CY2024Q3	us-gaap	Professional Fees ProfessionalFees	1206000	usd
CY2024Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2951000	usd
CY2023Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2432000	usd
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	8667000	usd
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6751000	usd
	us-gaap	Net Income Loss NetIncomeLoss	69376000	usd
CY2024Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.68
CY2023Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.60
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.20
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.25
CY2024Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.68
CY2023Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.60
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.20
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.24
CY2024Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.36
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	-1094000	usd
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	-33032000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-9551000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-49727000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-10443000	usd
	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-1339000	usd
	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-4658000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-7545000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-39284000	usd
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-5037000	usd
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-17521000	usd
CY2024Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	12979000	usd
CY2023Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-20835000	usd
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	61671000	usd
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	51855000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	773288000	usd
CY2024Q1	us-gaap	Net Income Loss NetIncomeLoss	21511000	usd
CY2024Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	2603000	usd
CY2024Q1	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	306000	usd
CY2023Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	122021000	usd
CY2023Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	560510000	usd
CY2024Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1433097000	usd
CY2024Q3	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	9722000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4578048000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4524510000	usd
CY2024Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	44276000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	42674000	usd
CY2024Q3	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	32643000	usd
CY2024Q3	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	137489000	usd
CY2023Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	136330000	usd
CY2024Q3	us-gaap	Other Assets OtherAssets	30616000	usd
CY2023Q4	us-gaap	Other Assets OtherAssets	31627000	usd
CY2024Q3	us-gaap	Assets Assets	8362263000	usd
CY2023Q4	us-gaap	Assets Assets	8284914000	usd
CY2024Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	1377022000	usd
CY2024Q3	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	5058680000	usd
CY2023Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	5159274000	usd
CY2024Q3	us-gaap	Deposits Deposits	6435702000	usd
CY2023Q4	us-gaap	Deposits Deposits	6549681000	usd
CY2024Q3	us-gaap	Federal Funds Purchased And Securities Sold Under Agreements To Repurchase FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	105810000	usd
CY2023Q4	us-gaap	Federal Funds Purchased And Securities Sold Under Agreements To Repurchase FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase	509820000	usd
CY2024Q3	us-gaap	Federal Home Loan Bank Advances Branch Of Fhlb Bank Amount Of Advances By Branch FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch	760046000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Branch Of Fhlb Bank Amount Of Advances By Branch FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch	212648000	usd
CY2024Q3	us-gaap	Subordinated Debt SubordinatedDebt	92006000	usd
CY2023Q4	us-gaap	Subordinated Debt SubordinatedDebt	93877000	usd
CY2024Q3	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	60273000	usd
CY2023Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	60270000	usd
CY2024Q3	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	19904000	usd
CY2023Q4	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	0	usd
CY2024Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	8362263000	usd
	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	209791000	usd
CY2023Q3	us-gaap	Interest Expense Other InterestExpenseOther	5540000	usd
CY2023Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	53273000	usd
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	162420000	usd
CY2024Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	115000	usd
CY2023Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	96000	usd
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	-101000	usd
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	385000	usd
CY2024Q3	sbsi	Fees And Commissions Fiduciary And Trust Activity FeesAndCommissionsFiduciaryAndTrustActivity	1628000	usd
CY2023Q3	sbsi	Fees And Commissions Fiduciary And Trust Activity FeesAndCommissionsFiduciaryAndTrustActivity	1522000	usd
	sbsi	Fees And Commissions Fiduciary And Trust Activity FeesAndCommissionsFiduciaryAndTrustActivity	4420000	usd
	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	3163000	usd
	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	2361000	usd
CY2024Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	233000	usd
CY2023Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1062000	usd
CY2023Q3	us-gaap	Professional Fees ProfessionalFees	1472000	usd
	us-gaap	Professional Fees ProfessionalFees	3435000	usd
	us-gaap	Professional Fees ProfessionalFees	4036000	usd
CY2024Q3	us-gaap	Communication Communication	423000	usd
CY2023Q3	us-gaap	Communication Communication	359000	usd
	us-gaap	Communication Communication	1282000	usd
	us-gaap	Communication Communication	1034000	usd
CY2024Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	939000	usd
CY2023Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	902000	usd
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2859000	usd
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2666000	usd
CY2024Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	278000	usd
CY2023Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	407000	usd
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	922000	usd
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1327000	usd
CY2024Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3543000	usd
CY2023Q3	us-gaap	Noninterest Expense NoninterestExpense	35553000	usd
	us-gaap	Noninterest Expense NoninterestExpense	108978000	usd
	us-gaap	Noninterest Expense NoninterestExpense	105395000	usd
CY2024Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	24914000	usd
CY2023Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	21569000	usd
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	80932000	usd
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	81607000	usd
CY2024Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4390000	usd
CY2023Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3120000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	14224000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12231000	usd
CY2024Q3	us-gaap	Net Income Loss NetIncomeLoss	20524000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	18449000	usd
	us-gaap	Net Income Loss NetIncomeLoss	66708000	usd
CY2023Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.35
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.08
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.05
CY2024Q3	us-gaap	Net Income Loss NetIncomeLoss	20524000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	18449000	usd
	us-gaap	Net Income Loss NetIncomeLoss	66708000	usd
	us-gaap	Net Income Loss NetIncomeLoss	69376000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	6593000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	-52882000	usd
	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-6376000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-2006000	usd
CY2024Q1	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	10683	shares
CY2023Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	30543000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	30332000	shares
CY2024Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.68
CY2023Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.60
CY2023Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	30502000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	30276000	shares
CY2023Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	41000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	56000	shares
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.20
CY2023Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.60
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.20
CY2024Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	539000	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	534000	shares
CY2024Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	1172000	usd
CY2023Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	3336000	usd
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	7047000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	22769000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	137000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	458010000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	34993000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	480779000	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	35130000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	28366000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	367000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	953974000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	127499000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	982340000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	127866000	usd
	dei	Local Phone Number LocalPhoneNumber	531-7111
CY2024Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	333825000	usd
CY2023Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	10894000	usd
CY2024Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	14007000	usd
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	14837000	usd
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2024
CY2023Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	391719000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	11936000	usd
CY2023Q4	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	9691000	usd
CY2024Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	768000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4533772000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4481836000	usd
CY2024Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	138811000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	138950000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	16704000	usd
CY2024Q3	us-gaap	Other Liabilities OtherLiabilities	67349000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	68626000	usd
CY2024Q3	us-gaap	Liabilities Liabilities	7557009000	usd
CY2023Q4	us-gaap	Liabilities Liabilities	7511626000	usd
CY2024Q3	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2023Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2024Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.25
CY2023Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.25
CY2023Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	80000000	shares
CY2024Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	80000000	shares
CY2024Q3	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	38070150	shares
CY2023Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	38039706	shares
CY2024Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	71896000	usd
CY2023Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	64110000	usd
	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	12585000	usd
CY2024Q3	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	582000	usd
CY2023Q3	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	265000	usd
	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	1488000	usd
	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	889000	usd
CY2024Q3	us-gaap	Interest Income Other InterestIncomeOther	4286000	usd
	sbsi	Fees And Commissions Fiduciary And Trust Activity FeesAndCommissionsFiduciaryAndTrustActivity	4479000	usd
CY2024Q3	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	857000	usd
CY2023Q3	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	790000	usd
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	3408000	usd
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	3221000	usd
CY2024Q3	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	1068000	usd
CY2023Q3	us-gaap	Brokerage Commissions Revenue BrokerageCommissionsRevenue	760000	usd
CY2023Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3524000	usd
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	10174000	usd
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	9889000	usd
CY2024Q3	us-gaap	Noninterest Expense NoninterestExpense	36332000	usd
CY2024Q3	sbsi	Amortizationof Unrealized Gains Losseson Securities Transferred Between Availablefor Sale And Heldto Maturity Debt Securities Before Tax AmortizationofUnrealizedGainsLossesonSecuritiesTransferredBetweenAvailableforSaleAndHeldtoMaturityDebtSecuritiesBeforeTax	-2119000	usd
CY2023Q3	sbsi	Amortizationof Unrealized Gains Losseson Securities Transferred Between Availablefor Sale And Heldto Maturity Debt Securities Before Tax AmortizationofUnrealizedGainsLossesonSecuritiesTransferredBetweenAvailableforSaleAndHeldtoMaturityDebtSecuritiesBeforeTax	-2008000	usd
	sbsi	Amortizationof Unrealized Gains Losseson Securities Transferred Between Availablefor Sale And Heldto Maturity Debt Securities Before Tax AmortizationofUnrealizedGainsLossesonSecuritiesTransferredBetweenAvailableforSaleAndHeldtoMaturityDebtSecuritiesBeforeTax	-6210000	usd
	sbsi	Amortizationof Unrealized Gains Losseson Securities Transferred Between Availablefor Sale And Heldto Maturity Debt Securities Before Tax AmortizationofUnrealizedGainsLossesonSecuritiesTransferredBetweenAvailableforSaleAndHeldtoMaturityDebtSecuritiesBeforeTax	-5989000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-1929000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	11000	usd
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-2510000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-13658000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	7377000	usd
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	4641000	usd
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	16277000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	5688000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	6408000	usd
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	18112000	usd
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	17570000	usd
CY2024Q3	sbsi	Other Comprehensive Income Loss Defined Benefit Plan Gain Lossand Prior Service Cost Credit Reclassification Adjustmentfrom Aoc Ibefore Tax OtherComprehensiveIncomeLossDefinedBenefitPlanGainLossandPriorServiceCostCreditReclassificationAdjustmentfromAOCIbeforeTax	156000	usd
CY2023Q3	sbsi	Other Comprehensive Income Loss Defined Benefit Plan Gain Lossand Prior Service Cost Credit Reclassification Adjustmentfrom Aoc Ibefore Tax OtherComprehensiveIncomeLossDefinedBenefitPlanGainLossandPriorServiceCostCreditReclassificationAdjustmentfromAOCIbeforeTax	189000	usd
	sbsi	Other Comprehensive Income Loss Defined Benefit Plan Gain Lossand Prior Service Cost Credit Reclassification Adjustmentfrom Aoc Ibefore Tax OtherComprehensiveIncomeLossDefinedBenefitPlanGainLossandPriorServiceCostCreditReclassificationAdjustmentfromAOCIbeforeTax	471000	usd
	sbsi	Other Comprehensive Income Loss Defined Benefit Plan Gain Lossand Prior Service Cost Credit Reclassification Adjustmentfrom Aoc Ibefore Tax OtherComprehensiveIncomeLossDefinedBenefitPlanGainLossandPriorServiceCostCreditReclassificationAdjustmentfromAOCIbeforeTax	567000	usd
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Quarterly Report DocumentQuarterlyReport	true
CY2024Q3	us-gaap	Federal Funds Sold FederalFundsSold	22325000	usd
CY2023Q4	us-gaap	Federal Funds Sold FederalFundsSold	46770000	usd
CY2024Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	486297000	usd
CY2024Q3	us-gaap	Goodwill Goodwill	201116000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	201116000	usd
CY2024Q3	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	2003000	usd
CY2023Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	2925000	usd
CY2023Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	1390407000	usd
CY2024Q3	us-gaap	Interest Expense Operating InterestExpenseOperating	50239000	usd
CY2023Q3	us-gaap	Interest Expense Operating InterestExpenseOperating	39805000	usd
	us-gaap	Interest Expense Operating InterestExpenseOperating	150227000	usd
	us-gaap	Interest Expense Operating InterestExpenseOperating	100260000	usd
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-5590000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-1002000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	0	usd
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-1002000	usd
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	0	usd
	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-22179000	usd
CY2024Q1	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	756000	usd
CY2024Q1	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	23575	shares
CY2024Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	350000	usd
CY2024Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.36
CY2024Q1	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10892000	usd
CY2024Q1	us-gaap	Stockholders Equity StockholdersEquity	787922000	usd
CY2024Q2	us-gaap	Net Income Loss NetIncomeLoss	24673000	usd
CY2024Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-95000	usd
CY2024Q2	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	11060	shares
CY2024Q2	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	290000	usd
CY2024Q2	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	57966	shares
CY2024Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1510000	usd
CY2024Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	761000	usd
CY2024Q2	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	23778	shares
CY2024Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-166000	usd
CY2024Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.36
CY2024Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10905000	usd
CY2024Q2	us-gaap	Stockholders Equity StockholdersEquity	800970000	usd
CY2024Q3	us-gaap	Net Income Loss NetIncomeLoss	20524000	usd
CY2024Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-7545000	usd
CY2024Q3	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	8701	shares
CY2024Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	290000	usd
CY2024Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	987000	usd
CY2024Q3	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	38553	shares
CY2024Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	933000	usd
CY2024Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.36
CY2024Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10905000	usd
CY2024Q3	us-gaap	Stockholders Equity StockholdersEquity	805254000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	745997000	usd
CY2023Q1	us-gaap	Net Income Loss NetIncomeLoss	26034000	usd
CY2023Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4144000	usd
CY2023Q1	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	8026	shares
CY2023Q1	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	302000	usd
CY2023Q1	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	457394	shares
CY2023Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	15945000	usd
CY2023Q1	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	914000	usd
CY2023Q1	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	23919	shares
CY2023Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	572000	usd
CY2023Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.35
CY2023Q1	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10988000	usd
CY2023Q1	us-gaap	Stockholders Equity StockholdersEquity	751030000	usd
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	24893000	usd
CY2023Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	17619000	usd
CY2023Q2	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	10390	shares
CY2023Q2	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	299000	usd
CY2023Q2	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	618831	shares
CY2023Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	18725000	usd
CY2023Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	924000	usd
CY2023Q2	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	19065	shares
CY2023Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-159000	usd
CY2023Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.35
CY2023Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10720000	usd
CY2023Q2	us-gaap	Stockholders Equity StockholdersEquity	765161000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	18449000	usd
CY2023Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-39284000	usd
CY2023Q3	us-gaap	Stock Issued During Period Shares Dividend Reinvestment Plan StockIssuedDuringPeriodSharesDividendReinvestmentPlan	10007	shares
CY2023Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	307000	usd
CY2023Q3	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	212388	shares
CY2023Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	6237000	usd
CY2023Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	875000	usd
CY2023Q3	us-gaap	Stock Issued During Period Shares Share Based Compensation StockIssuedDuringPeriodSharesShareBasedCompensation	8670	shares
CY2023Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	11000	usd
CY2023Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.35
CY2023Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	10687000	usd
CY2023Q3	us-gaap	Stockholders Equity StockholdersEquity	728595000	usd
	us-gaap	Profit Loss ProfitLoss	66708000	usd
	us-gaap	Profit Loss ProfitLoss	69376000	usd
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	7518000	usd
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	7972000	usd
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-4657000	usd
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-3791000	usd
	us-gaap	Investment Income Net Amortization Of Discount And Premium InvestmentIncomeNetAmortizationOfDiscountAndPremium	-298000	usd
	us-gaap	Investment Income Net Amortization Of Discount And Premium InvestmentIncomeNetAmortizationOfDiscountAndPremium	-296000	usd
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	1962000	usd
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6873000	usd
	us-gaap	Share Based Compensation ShareBasedCompensation	2504000	usd
	us-gaap	Share Based Compensation ShareBasedCompensation	2713000	usd
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-878000	usd
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1868000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-2510000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-5590000	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	5058000	usd
	sbsi	Available For Sale Securities Loss On Impairment AvailableForSaleSecuritiesLossOnImpairment	868000	usd
	sbsi	Available For Sale Securities Loss On Impairment AvailableForSaleSecuritiesLossOnImpairment	0	usd
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-28000	usd
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-106000	usd
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	13423000	usd
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	12941000	usd
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	11289000	usd
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	13656000	usd
	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	-412000	usd
	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	0	usd
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-95000	usd
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	53000	usd
	us-gaap	Gain Loss On Repurchase Of Debt Instrument GainLossOnRepurchaseOfDebtInstrument	178000	usd
	us-gaap	Gain Loss On Repurchase Of Debt Instrument GainLossOnRepurchaseOfDebtInstrument	587000	usd
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-12601000	usd
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-9704000	usd
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	39564000	usd
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	5665000	usd
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-449000	usd
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	10545000	usd
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	1815000	usd
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	33434000	usd
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	63041000	usd
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	136454000	usd
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	752237000	usd
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1137694000	usd
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	126248000	usd
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	747434000	usd
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	545836000	usd
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	324964000	usd
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	20951000	usd
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	21010000	usd
	sbsi	Proceeds From Sales Of Equity Securities ProceedsFromSalesOfEquitySecurities	0	usd
	sbsi	Proceeds From Sales Of Equity Securities ProceedsFromSalesOfEquitySecurities	6679000	usd
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	56115000	usd
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	30767000	usd
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	84501000	usd
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	34249000	usd
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	50985000	usd
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	274843000	usd
	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	7600000	usd
	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	0	usd
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	6094000	usd
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	5071000	usd
	us-gaap	Payments For Proceeds From Life Insurance Policies PaymentsForProceedsFromLifeInsurancePolicies	-4035000	usd
	us-gaap	Payments For Proceeds From Life Insurance Policies PaymentsForProceedsFromLifeInsurancePolicies	-951000	usd
	sbsi	Proceeds From Sale Of Property Plant And Equipment Net ProceedsFromSaleOfPropertyPlantAndEquipmentNet	17000	usd
	sbsi	Proceeds From Sale Of Property Plant And Equipment Net ProceedsFromSaleOfPropertyPlantAndEquipmentNet	430000	usd
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	278000	usd
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	146000	usd
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	114000	usd
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	168000	usd
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-132623000	usd
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-319308000	usd
	us-gaap	Net Change Interest And Noninterest Bearing Deposits Domestic NetChangeInterestAndNoninterestBearingDepositsDomestic	-114005000	usd
	us-gaap	Net Change Interest And Noninterest Bearing Deposits Domestic NetChangeInterestAndNoninterestBearingDepositsDomestic	151446000	usd
	us-gaap	Increase Decrease In Federal Funds Purchased And Securities Sold Under Agreements To Repurchase Net IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet	-404010000	usd
	us-gaap	Increase Decrease In Federal Funds Purchased And Securities Sold Under Agreements To Repurchase Net IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet	174056000	usd
	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	6068951000	usd
	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	1659000000	usd
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	5521553000	usd
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	1599529000	usd
	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	1805000	usd
	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	4365000	usd
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	1403000	usd
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	705000	usd
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	286000	usd
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	281000	usd
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1510000	usd
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	40120000	usd
	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	886000	usd
	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	908000	usd
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	32702000	usd
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	32395000	usd
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-4631000	usd
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	309425000	usd
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-74213000	usd
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	126571000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	560510000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	199252000	usd
CY2024Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	486297000	usd
CY2023Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	325823000	usd
	us-gaap	Interest Paid Net InterestPaidNet	150676000	usd
	us-gaap	Interest Paid Net InterestPaidNet	89715000	usd
	us-gaap	Income Taxes Paid IncomeTaxesPaid	12000000	usd
	us-gaap	Income Taxes Paid IncomeTaxesPaid	12250000	usd
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	806000	usd
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	127000	usd
CY2024Q3	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	19904000	usd
CY2023Q3	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	24917000	usd
CY2024Q3	sbsi	Unsettled Trades To Repurchase Common Stock UnsettledTradesToRepurchaseCommonStock	0	usd
CY2023Q3	sbsi	Unsettled Trades To Repurchase Common Stock UnsettledTradesToRepurchaseCommonStock	541000	usd
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="margin-bottom:6pt;margin-top:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Accounting Changes and Reclassifications</span></div>Certain prior period amounts may be reclassified to conform to current year presentation.
CY2024Q3	us-gaap	Net Income Loss NetIncomeLoss	20524000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	18449000	usd
	us-gaap	Net Income Loss NetIncomeLoss	66708000	usd
	us-gaap	Net Income Loss NetIncomeLoss	69376000	usd
CY2024Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	14000	usd
CY2023Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	10000	usd
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	41000	usd
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	29000	usd
CY2024Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	20510000	usd
CY2023Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	18439000	usd
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	66667000	usd
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	69347000	usd
CY2024Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	30286000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	30862000	shares
CY2024Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	84000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	54000	shares
CY2024Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	30370000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	30916000	shares
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.25
CY2024Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.68
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.24
CY2023Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	611000	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	571000	shares
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	4285000	usd
CY2024Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1433097000	usd
CY2024Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	10470000	usd
CY2024Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	35130000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1408437000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1288403000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	8986000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	127866000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1169523000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1332467000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	3658000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	39831000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1296294000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1307053000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	10571000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	151462000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1166162000	usd
CY2023	sbsi	Securities Transferred From Available For Sale To Held To Maturity SecuritiesTransferredFromAvailableForSaleToHeldToMaturity	0	usd
	sbsi	Securities Transferred From Available For Sale To Held To Maturity SecuritiesTransferredFromAvailableForSaleToHeldToMaturity	0	usd
CY2024Q3	sbsi	Transferred Securities Unrealized Loss Before Tax TransferredSecuritiesUnrealizedLossBeforeTax	107300000	usd
CY2024Q3	sbsi	Securities Transferred Unrealized Loss Net Of Tax SecuritiesTransferredUnrealizedLossNetOfTax	84800000	usd
CY2023Q4	sbsi	Transferred Securities Unrealized Loss Before Tax TransferredSecuritiesUnrealizedLossBeforeTax	113500000	usd
CY2023Q4	sbsi	Securities Transferred Unrealized Loss Net Of Tax SecuritiesTransferredUnrealizedLossNetOfTax	89700000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	185339000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1165000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	560939000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	38666000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	746278000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	39831000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	26505000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1258000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	939087000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	150204000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	965592000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	151462000	usd
CY2024Q3	sbsi	Debt Securities Available For Sale Realized Loss Impairment DebtSecuritiesAvailableForSaleRealizedLossImpairment	868000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	usd
CY2024Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	271	debt_security
CY2024Q3	sbsi	Held To Maturity Securities Number Of Bonds Below Investment Grade HeldToMaturitySecuritiesNumberOfBondsBelowInvestmentGrade	2	bonds
CY2024Q3	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	8400000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	8200000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	15400000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	13700000	usd
CY2024Q3	us-gaap	Interest Income Securities Us Treasury And Other Us Government InterestIncomeSecuritiesUSTreasuryAndOtherUSGovernment	2315000	usd
CY2023Q3	us-gaap	Interest Income Securities Us Treasury And Other Us Government InterestIncomeSecuritiesUSTreasuryAndOtherUSGovernment	3784000	usd
CY2024Q3	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	12994000	usd
CY2023Q3	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	16940000	usd
CY2024Q3	us-gaap	Interest Income Securities Corporate Debt Operating InterestIncomeSecuritiesCorporateDebtOperating	1654000	usd
CY2023Q3	us-gaap	Interest Income Securities Corporate Debt Operating InterestIncomeSecuritiesCorporateDebtOperating	1765000	usd
CY2024Q3	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	11976000	usd
CY2023Q3	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	4426000	usd
CY2024Q3	us-gaap	Interest And Other Income InterestAndOtherIncome	28939000	usd
CY2023Q3	us-gaap	Interest And Other Income InterestAndOtherIncome	26915000	usd
	us-gaap	Interest Income Securities Us Treasury And Other Us Government InterestIncomeSecuritiesUSTreasuryAndOtherUSGovernment	6404000	usd
	us-gaap	Interest Income Securities Us Treasury And Other Us Government InterestIncomeSecuritiesUSTreasuryAndOtherUSGovernment	8307000	usd
	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	41151000	usd
	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	50940000	usd
	us-gaap	Interest Income Securities Corporate Debt Operating InterestIncomeSecuritiesCorporateDebtOperating	5182000	usd
	us-gaap	Interest Income Securities Corporate Debt Operating InterestIncomeSecuritiesCorporateDebtOperating	5363000	usd
	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	33179000	usd
	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	12585000	usd
	us-gaap	Interest And Other Income InterestAndOtherIncome	85916000	usd
	us-gaap	Interest And Other Income InterestAndOtherIncome	77195000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-2500000	usd
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	6100000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	88000	usd
	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	3500000	usd
CY2024Q3	sbsi	Debt Securities Available For Sale Realized Loss Impairment DebtSecuritiesAvailableForSaleRealizedLossImpairment	868000	usd
CY2024Q3	sbsi	Debt Securities Available For Sale Realized Loss Sale Of Municipal Securities DebtSecuritiesAvailableForSaleRealizedLossSaleOfMunicipalSecurities	685000	usd
CY2024Q3	us-gaap	Availableforsale Securities Sold At Par AvailableforsaleSecuritiesSoldAtPar	10000000	usd
CY2024Q3	sbsi	Debt Securities Available For Sale Realized Loss Unwind Of Fair Value Hedges DebtSecuritiesAvailableForSaleRealizedLossUnwindOfFairValueHedges	183000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-5600000	usd
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	7000000.0	usd
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	1400000	usd
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	usd
CY2024Q3	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	usd
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	usd
CY2023Q3	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	176356000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	176436000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	1797000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	1810000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	25600000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	25193000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	453785000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	422014000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	657538000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	625453000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	775559000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	782984000	usd
CY2024Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1433097000	usd
CY2024Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1408437000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Allocated And Single Maturity Date Rolling Within One Year DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateRollingWithinOneYear	4118000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	4087000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Allocated And Single Maturity Date Rolling After One Through Five Years DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateRollingAfterOneThroughFiveYears	11920000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	11695000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Allocated And Single Maturity Date Rolling After5 Through10 Years DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateRollingAfter5Through10Years	141206000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	131105000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Allocated And Single Maturity Date Rolling After10 Years DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateRollingAfter10Years	1015088000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	913482000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Allocated And Single Maturity Date DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDate	1172332000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	1060369000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss Maturity Without Single Maturity Date DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityWithoutSingleMaturityDate	116071000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	109154000	usd
CY2024Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1288403000	usd
CY2024Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1169523000	usd
CY2024Q3	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	9700000	usd
CY2024Q3	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	191000	usd
CY2023Q3	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	-163000	usd
	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	112000	usd
	us-gaap	Unrealized Gain Loss On Investments UnrealizedGainLossOnInvestments	4895000	usd
CY2024Q3	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
CY2023Q3	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	0	usd
	sbsi	Equity Securities Realized Gain EquitySecuritiesRealizedGain	5058000	usd
CY2024Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	191000	usd
CY2023Q3	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-163000	usd
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	112000	usd
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	-163000	usd
CY2024Q3	sbsi	Other Than Temporarily Impaired Equity Investments OtherThanTemporarilyImpairedEquityInvestments	0	usd
CY2024Q3	sbsi	Federal Home Loan Bank Stock With Other Than Temporary Impairment FederalHomeLoanBankStockWithOtherThanTemporaryImpairment	0	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4578048000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4524510000	usd
CY2024Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	44276000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	42674000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4533772000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4481836000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	367990000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	796237000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	1215364000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	826096000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	339901000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	725770000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	306690000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4578048000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff	1235000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	398000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	120000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	69000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	43000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	263000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	0	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	2128000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	839785000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	1199738000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	961538000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	365469000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	217076000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	613986000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	326918000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4524510000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff	2427000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	586000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	105000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	46000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	818000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	222000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	0	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	4204000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4578048000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	4524510000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Modified Period FinancingReceivableExcludingAccruedInterestModifiedPeriod	362000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Modified Period FinancingReceivableExcludingAccruedInterestModifiedPeriod	506000	usd
CY2024Q3	sbsi	Financing Receivable Nonaccrual Interest Income Reversal FinancingReceivableNonaccrualInterestIncomeReversal	13000	usd
	sbsi	Financing Receivable Nonaccrual Interest Income Reversal FinancingReceivableNonaccrualInterestIncomeReversal	75000	usd
CY2023Q3	sbsi	Financing Receivable Nonaccrual Interest Income Reversal FinancingReceivableNonaccrualInterestIncomeReversal	13000	usd
	sbsi	Financing Receivable Nonaccrual Interest Income Reversal FinancingReceivableNonaccrualInterestIncomeReversal	78000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	4500000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	1000000.0	usd
CY2024Q3	sbsi	Financing Receivable Collateral Dependent FinancingReceivableCollateralDependent	11500000	usd
CY2023Q4	sbsi	Financing Receivable Collateral Dependent FinancingReceivableCollateralDependent	7500000	usd
CY2024Q3	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	0	usd
CY2023Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	1000000	usd
CY2024Q3	sbsi	Financing Receivable Modified In Period Number Of Loans FinancingReceivableModifiedInPeriodNumberOfLoans	3	loans
	us-gaap	Financing Receivable Excluding Accrued Interest Modified Period FinancingReceivableExcludingAccruedInterestModifiedPeriod	362000	usd
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	289000	usd
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	usd
CY2024Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	42407000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	773000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	365000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	408000	usd
CY2024Q3	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	2277000	usd
CY2024Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	44276000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	42674000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	2128000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	1156000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	972000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	2574000	usd
CY2024Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	44276000	usd
CY2023Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	36303000	usd
CY2023Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	1262000	usd
CY2023Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	378000	usd
CY2023Q3	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	884000	usd
CY2023Q3	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	6341000	usd
CY2023Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	41760000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	36515000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	2632000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	1170000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	1462000	usd
	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	6707000	usd
CY2023Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	41760000	usd
CY2024Q3	us-gaap	Financing Receivable Accrued Interest Before Allowance For Credit Loss FinancingReceivableAccruedInterestBeforeAllowanceForCreditLoss	21300000	usd
CY2023Q4	us-gaap	Financing Receivable Accrued Interest Before Allowance For Credit Loss FinancingReceivableAccruedInterestBeforeAllowanceForCreditLoss	21300000	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In The Next Rolling Twelve Months BorrowedFundsMaturitiesRepaymentsOfPrincipalInTheNextRollingTwelveMonths	864524000	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In Rolling Year Two BorrowedFundsMaturitiesRepaymentsOfPrincipalInRollingYearTwo	582000	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In Rolling Year Three BorrowedFundsMaturitiesRepaymentsOfPrincipalInRollingYearThree	401000	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In Rolling Year Four BorrowedFundsMaturitiesRepaymentsOfPrincipalInRollingYearFour	349000	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In Rolling Year Five BorrowedFundsMaturitiesRepaymentsOfPrincipalInRollingYearFive	0	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal In Rolling After Year Five BorrowedFundsMaturitiesRepaymentsOfPrincipalInRollingAfterYearFive	0	usd
CY2024Q3	sbsi	Borrowed Funds Maturities Repayments Of Principal BorrowedFundsMaturitiesRepaymentsOfPrincipal	865856000	usd
CY2024Q3	sbsi	Line Of Credit Facility Number Of Credit Lines Maintained By Company LineOfCreditFacilityNumberOfCreditLinesMaintainedByCompany	3	credit_line
CY2023Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	usd
CY2024Q3	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	usd
CY2024Q3	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	80800000	usd
CY2023Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	92100000	usd
	sbsi	Repurchase Agreement Counterparty Maturityof Agreements RepurchaseAgreementCounterpartyMaturityofAgreements	P1Y
CY2024Q3	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Amount Of Available Unused Funds FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds	1800000000	usd
CY2024Q3	us-gaap	Subordinated Debt SubordinatedDebt	92006000	usd
CY2023Q4	us-gaap	Subordinated Debt SubordinatedDebt	93877000	usd
CY2024Q3	us-gaap	Other Long Term Debt OtherLongTermDebt	60273000	usd
CY2023Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	60270000	usd
CY2024Q3	us-gaap	Long Term Debt LongTermDebt	152279000	usd
CY2023Q4	us-gaap	Long Term Debt LongTermDebt	154147000	usd
	sbsi	Adjustment To Pension Liability AdjustmentToPensionLiability	531000	usd
	sbsi	Adjustment To Pension Liability AdjustmentToPensionLiability	-567000	usd
	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	3500000	usd
CY2023	us-gaap	Gain Loss On Oil And Gas Hedging Activity GainLossOnOilAndGasHedgingActivity	6500000	usd
CY2024Q3	us-gaap	Prepayable Financial Asset Closed Portfolio Last Of Layer Amortized Cost PrepayableFinancialAssetClosedPortfolioLastOfLayerAmortizedCost	271400000	usd
CY2024Q3	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	22300000	usd
CY2023Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	46800000	usd
CY2024Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	33665000	usd
CY2024Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	23806000	usd
CY2023Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	56639000	usd
CY2023Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	25684000	usd
CY2024Q3	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	9451000	usd
CY2024Q3	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	9451000	usd
CY2023Q4	us-gaap	Derivative Asset Fair Value Gross Liability DerivativeAssetFairValueGrossLiability	7435000	usd
CY2023Q4	us-gaap	Derivative Liability Fair Value Gross Asset DerivativeLiabilityFairValueGrossAsset	7435000	usd
CY2024Q3	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	22300000	usd
CY2024Q3	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	0	usd
CY2023Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	46760000	usd
CY2023Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	0	usd
CY2024Q3	us-gaap	Derivative Assets DerivativeAssets	1914000	usd
CY2024Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	14355000	usd
CY2023Q4	us-gaap	Derivative Assets DerivativeAssets	2444000	usd
CY2023Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	18249000	usd
CY2024Q3	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	5283000	usd
CY2023Q3	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	4672000	usd
	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	15102000	usd
	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	14099000	usd
CY2024Q3	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-893000	usd
CY2023Q3	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1552000	usd
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-878000	usd
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1868000	usd
CY2024Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4390000	usd
CY2023Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3120000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	14224000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12231000	usd
CY2024Q3	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	32600000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	30400000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	usd
CY2024Q3	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	usd
CY2024Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4400000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	14200000	usd
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.176
CY2024Q3	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.176
CY2023Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3100000	usd
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12200000	usd
CY2023Q3	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.145
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.150
CY2024Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3208000	usd
CY2023Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3207000	usd
CY2023Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3932000	usd
CY2022Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3687000	usd
CY2024Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	112000	usd
CY2023Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	646000	usd
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-612000	usd
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	166000	usd
CY2024Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3320000	usd
CY2023Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3853000	usd
CY2024Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3320000	usd
CY2023Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	3853000	usd
CY2024Q3	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	895150000	usd
CY2023Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	1093150000	usd
CY2023Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	usd
CY2024Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	usd
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	372000	usd
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	603000	usd
CY2024Q3	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	19900000	usd
CY2024Q3	sbsi	Unsettled Trades To Sell Securities UnsettledTradesToSellSecurities	0	usd
CY2023Q4	sbsi	Unsettled Trades To Purchase Securities Liability UnsettledTradesToPurchaseSecuritiesLiability	0	usd
CY2023Q4	sbsi	Unsettled Trades To Sell Securities UnsettledTradesToSellSecurities	0	usd
CY2024Q3	sbsi	Unsettled Issuancesof Brokered C Ds UnsettledIssuancesofBrokeredCDs	0	usd
CY2023Q4	sbsi	Unsettled Issuancesof Brokered C Ds UnsettledIssuancesofBrokeredCDs	0	usd
CY2024Q3	ecd	Non Rule10b51 Arr Adopted Flag NonRule10b51ArrAdoptedFlag	false
CY2024Q3	ecd	Rule10b51 Arr Adopted Flag Rule10b51ArrAdoptedFlag	false
CY2024Q3	ecd	Non Rule10b51 Arr Trmntd Flag NonRule10b51ArrTrmntdFlag	false
CY2024Q3	ecd	Rule10b51 Arr Trmntd Flag Rule10b51ArrTrmntdFlag	false

Files In Submission

Name	View Source	Status
0000705432-24-000225-index-headers.html	Edgar Link	pending
0000705432-24-000225-index.html	Edgar Link	pending
0000705432-24-000225.txt	Edgar Link	pending
0000705432-24-000225-xbrl.zip	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
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R2.htm	Edgar Link	pending
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R28.htm	Edgar Link	pending
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R3.htm	Edgar Link	pending
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R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
sbsi-20240930.htm	Edgar Link	pending
sbsi-20240930.xsd	Edgar Link	pending
sbsi_093024ex311.htm	Edgar Link	pending
sbsi_093024ex312.htm	Edgar Link	pending
sbsi_093024ex32.htm	Edgar Link	pending
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sbsi-20240930_cal.xml	Edgar Link	unprocessable
sbsi-20240930_def.xml	Edgar Link	unprocessable
sbsi-20240930_lab.xml	Edgar Link	unprocessable
sbsi-20240930_pre.xml	Edgar Link	unprocessable
sbsi-20240930_htm.xml	Edgar Link	completed

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$SBSI
SOUTHSIDE BANCSHARES INC Stock $sbsi

2024 Q4 Form 10-Q Financial Statement

#000070543224000225 Filed on October 28, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SBSI SOUTHSIDE BANCSHARES INC Stock $sbsi

2024 Q4 Form 10-Q Financial Statement

#000070543224000225 Filed on October 28, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SBSI
SOUTHSIDE BANCSHARES INC Stock $sbsi