$FSBW
FS Bancorp, Inc. Stock $fsbw

$fsbw Overview Financials Valuation SEC Filings Company Website

2025 Q1 Form 10-K Financial Statement

#000143774925008049 Filed on March 17, 2025

Income Statement

Concept	2025 Q1	2024 Q4	2024
Revenue			$184.8M
YoY Change			3907.74%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin			$13.53M
YoY Change			3.51%
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization			$2.500M
YoY Change			-3.85%
% of Gross Profit
Operating Expenses			$13.53M
YoY Change			3.51%
Operating Profit
YoY Change
Interest Expense
YoY Change
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income			$41.58M
YoY Change			-8.15%
Income Tax			$6.557M
% Of Pretax Income			15.77%
Net Earnings			$35.02M
YoY Change			-2.85%
Net Earnings / Revenue			18.95%
Basic Earnings Per Share			$4.48
Diluted Earnings Per Share			$4.36
COMMON SHARES
Basic Shares Outstanding	7.763M	7.817M	7.698M
Diluted Shares Outstanding			7.893M

Balance Sheet

Concept	2025 Q1	2024 Q4	2024
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents		$31.64M
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		$29.76M
YoY Change		-2.69%
Goodwill		$3.600M
YoY Change		0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets		$3.029B
YoY Change		1.9%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt		$307.8M
YoY Change		228.34%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities
YoY Change
LONG-TERM LIABILITIES
Long-Term Debt
YoY Change
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities
YoY Change
TOTAL LIABILITIES
Total Short-Term Liabilities
Total Long-Term Liabilities
Total Liabilities		$2.733B
YoY Change		0.93%
SHAREHOLDERS EQUITY
Retained Earnings		$257.1M
YoY Change		11.62%
Common Stock		$78.00K
YoY Change		0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity		$295.8M
YoY Change
Total Liabilities & Shareholders Equity		$3.029B
YoY Change		1.9%

Cashflow Statement

Concept	2025 Q1	2024 Q4	2024
OPERATING ACTIVITIES
Net Income			$35.02M
YoY Change			-2.85%
Depreciation, Depletion And Amortization			$2.500M
YoY Change			-3.85%
Cash From Operating Activities			$50.82M
YoY Change			-34.56%
INVESTING ACTIVITIES
Capital Expenditures			$1.635M
YoY Change			-2.15%
Acquisitions
YoY Change
Other Investing Activities
YoY Change
Cash From Investing Activities			-$104.2M
YoY Change			-234.16%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$2.508M
YoY Change			1024.66%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities			$19.32M
YoY Change			-114.74%
NET CHANGE
Cash From Operating Activities			$50.82M
Cash From Investing Activities			-$104.2M
Cash From Financing Activities			$19.32M
Net Change In Cash			-$34.06M
YoY Change			-240.41%
FREE CASH FLOW
Cash From Operating Activities			$50.82M
Capital Expenditures			$1.635M
Free Cash Flow			$49.19M
YoY Change			-35.28%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2024	dei	Entity Central Index Key EntityCentralIndexKey	0001530249
CY2024	us-gaap	Labor And Related Expense LaborAndRelatedExpense	55092000	usd
CY2023	us-gaap	Labor And Related Expense LaborAndRelatedExpense	53622000	usd
CY2022	us-gaap	Labor And Related Expense LaborAndRelatedExpense	47632000	usd
CY2024	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	13529000	usd
CY2023	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	13070000	usd
CY2022	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	10743000	usd
CY2024	us-gaap	Occupancy Net OccupancyNet	6857000	usd
CY2023	us-gaap	Occupancy Net OccupancyNet	6378000	usd
CY2022	us-gaap	Occupancy Net OccupancyNet	5165000	usd
CY2024	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	8424000	usd
CY2023	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6852000	usd
CY2022	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6062000	usd
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CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	148000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-0	usd
CY2024	us-gaap	Loan Processing Fee LoanProcessingFee	2685000	usd
CY2023	us-gaap	Loan Processing Fee LoanProcessingFee	2574000	usd
CY2022	us-gaap	Loan Processing Fee LoanProcessingFee	2718000	usd
CY2024	us-gaap	Professional Fees ProfessionalFees	4072000	usd
CY2023	us-gaap	Professional Fees ProfessionalFees	2584000	usd
CY2022	us-gaap	Professional Fees ProfessionalFees	3154000	usd
CY2024	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2005000	usd
CY2023	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2392000	usd
CY2022	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1224000	usd
CY2024	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1310000	usd
CY2023	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1349000	usd
CY2022	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	897000	usd
CY2024	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	0	usd
CY2023	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	1562000	usd
CY2022	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	898000	usd
CY2024	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3633000	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3464000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	691000	usd
CY2024	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-38000	usd
CY2023	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	48000	usd
CY2022	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-1000	usd
CY2024	us-gaap	Noninterest Expense NoninterestExpense	97569000	usd
CY2023	us-gaap	Noninterest Expense NoninterestExpense	93747000	usd
CY2022	us-gaap	Noninterest Expense NoninterestExpense	79183000	usd
CY2024	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	41581000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	45272000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	36988000	usd
CY2024	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6557000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2024	us-gaap	Net Income Loss NetIncomeLoss	35024000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2024	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.48
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.63
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CY2024	us-gaap	Net Income Loss NetIncomeLoss	35024000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2024	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-1171000	usd
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CY2024	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-252000	usd
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CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	1651000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	9844000	usd
CY2024	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	1664000	usd
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CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	209000	usd
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CY2023Q4	us-gaap	Debt Securities Held To Maturity Nonaccrual DebtSecuritiesHeldToMaturityNonaccrual	0	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	0	pure
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	7	pure
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	7	pure
CY2023	fsbw	Expected Credit Losses On Investments ExpectedCreditLossesOnInvestments	0	usd
CY2022	fsbw	Expected Credit Losses On Investments ExpectedCreditLossesOnInvestments	0	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2024Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss Statement Of Financial Position Extensible List FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2024#InterestReceivable
CY2023Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss Statement Of Financial Position Extensible List FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2024#InterestReceivable
CY2023	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	usd
CY2024Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P5Y
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2024	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3600000	usd
CY2024	ecd	Rule10b51 Arr Adopted Flag Rule10b51ArrAdoptedFlag	false
CY2024	ecd	Rule10b51 Arr Trmntd Flag Rule10b51ArrTrmntdFlag	false
CY2024	ecd	Non Rule10b51 Arr Trmntd Flag NonRule10b51ArrTrmntdFlag	false
CY2024	ecd	Non Rule10b51 Arr Adopted Flag NonRule10b51ArrAdoptedFlag	false
CY2024	dei	Document Type DocumentType	10-K
CY2024	dei	Document Annual Report DocumentAnnualReport	true
CY2024	dei	Document Period End Date DocumentPeriodEndDate	2024-12-31
CY2024	dei	Document Transition Report DocumentTransitionReport	false
CY2024	dei	Entity File Number EntityFileNumber	001-35589
CY2024	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	WA
CY2024	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	45-4585178
CY2024	dei	Entity Address Address Line1 EntityAddressAddressLine1	6920 220th Street SW
CY2024	dei	Entity Address City Or Town EntityAddressCityOrTown	Mountlake Terrace
CY2024	dei	Entity Address State Or Province EntityAddressStateOrProvince	WA
CY2024	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	98043
CY2024	dei	City Area Code CityAreaCode	425
CY2024	dei	Local Phone Number LocalPhoneNumber	771-5299
CY2024	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value per share
CY2024	dei	Trading Symbol TradingSymbol	FSBW
CY2024	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2024	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2024	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2024	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2024	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2024	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
CY2024	dei	Entity Small Business EntitySmallBusiness	true
CY2024	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2024	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2024	dei	Document Fin Stmt Error Correction Flag DocumentFinStmtErrorCorrectionFlag	false
CY2024	dei	Entity Shell Company EntityShellCompany	false
CY2024Q2	dei	Entity Public Float EntityPublicFloat	255164361	usd
CY2025Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	7762827
CY2024	us-gaap	Net Income Loss NetIncomeLoss	35024000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2024	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5511000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	4774000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6217000	usd
CY2024	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	10566000	usd
CY2023	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	12649000	usd
CY2022	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	14004000	usd
CY2024	dei	Auditor Name AuditorName	Moss Adams LLP
CY2024	dei	Auditor Location AuditorLocation	Everett, Washington
CY2024	dei	Auditor Firm AuditorFirmId	659
CY2024Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	19280000	usd
CY2023Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	17083000	usd
CY2024Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	12355000	usd
CY2023Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	48608000	usd
CY2024Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	31635000	usd
CY2023Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	65691000	usd
CY2024Q4	us-gaap	Certificates Of Deposit At Carrying Value CertificatesOfDepositAtCarryingValue	1727000	usd
CY2023Q4	us-gaap	Certificates Of Deposit At Carrying Value CertificatesOfDepositAtCarryingValue	24167000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	281175000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	292933000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	8455000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	8455000	usd
CY2024Q4	us-gaap	Loans Held For Sale Fair Value Disclosure LoansHeldForSaleFairValueDisclosure	27835000	usd
CY2023Q4	us-gaap	Loans Held For Sale Fair Value Disclosure LoansHeldForSaleFairValueDisclosure	25668000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	2501951000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	2401481000	usd
CY2024Q4	us-gaap	Interest Receivable InterestReceivable	13881000	usd
CY2023Q4	us-gaap	Interest Receivable InterestReceivable	14005000	usd
CY2024Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	29756000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	30578000	usd
CY2024Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	5378000	usd
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	6627000	usd
CY2024Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	15621000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2114000	usd
CY2024Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	7059000	usd
CY2023Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	6725000	usd
CY2024Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	38528000	usd
CY2023Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	37719000	usd
CY2024Q4	fsbw	Mortgage Servicing Asset Held For Sale MortgageServicingAssetHeldForSale	0	usd
CY2023Q4	fsbw	Mortgage Servicing Asset Held For Sale MortgageServicingAssetHeldForSale	8086000	usd
CY2024Q4	us-gaap	Goodwill Goodwill	3592000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	3592000	usd
CY2024Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	13710000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	17343000	usd
CY2024Q4	us-gaap	Other Assets OtherAssets	39670000	usd
CY2023Q4	us-gaap	Other Assets OtherAssets	18395000	usd
CY2024Q4	us-gaap	Assets Assets	3029177000	usd
CY2023Q4	us-gaap	Assets Assets	2972669000	usd
CY2024Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	638158000	usd
CY2023Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	670831000	usd
CY2024Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	1701260000	usd
CY2023Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	1851492000	usd
CY2024Q4	us-gaap	Deposits Deposits	2339418000	usd
CY2023Q4	us-gaap	Deposits Deposits	2522323000	usd
CY2024Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	307806000	usd
CY2023Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	93746000	usd
CY2024Q4	us-gaap	Subordinated Debt SubordinatedDebt	50000000	usd
CY2023Q4	us-gaap	Subordinated Debt SubordinatedDebt	50000000	usd
CY2024Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	406000	usd
CY2023Q4	us-gaap	Unamortized Debt Issuance Expense UnamortizedDebtIssuanceExpense	473000	usd
CY2024Q4	fsbw	Subordinated Debt Net Of Unamortized Debt Issuance Expense SubordinatedDebtNetOfUnamortizedDebtIssuanceExpense	49594000	usd
CY2023Q4	fsbw	Subordinated Debt Net Of Unamortized Debt Issuance Expense SubordinatedDebtNetOfUnamortizedDebtIssuanceExpense	49527000	usd
CY2024Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	5556000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	6848000	usd
CY2024Q4	us-gaap	Other Liabilities OtherLiabilities	31036000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	35737000	usd
CY2024Q4	us-gaap	Liabilities Liabilities	2733410000	usd
CY2023Q4	us-gaap	Liabilities Liabilities	2708181000	usd
CY2024Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	usd
CY2023Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	usd
CY2024Q4	us-gaap	Common Stock Value CommonStockValue	78000	usd
CY2023Q4	us-gaap	Common Stock Value CommonStockValue	78000	usd
CY2024Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	55716000	usd
CY2023Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	57362000	usd
CY2024Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	257113000	usd
CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	230354000	usd
CY2024Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-17140000	usd
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-23306000	usd
CY2024Q4	us-gaap	Stockholders Equity StockholdersEquity	295767000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	264488000	usd
CY2024Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3029177000	usd
CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2972669000	usd
CY2024	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	170857000	usd
CY2023	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	154945000	usd
CY2022	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	111648000	usd
CY2024	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	13980000	usd
CY2023	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	12247000	usd
CY2022	us-gaap	Investment Income Interest And Dividend InvestmentIncomeInterestAndDividend	7046000	usd
CY2024	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	184837000	usd
CY2023	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	167192000	usd
CY2022	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	118694000	usd
CY2024	us-gaap	Interest Expense Deposits InterestExpenseDeposits	53163000	usd
CY2023	us-gaap	Interest Expense Deposits InterestExpenseDeposits	36751000	usd
CY2022	us-gaap	Interest Expense Deposits InterestExpenseDeposits	9420000	usd
CY2024	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	6627000	usd
CY2023	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	5196000	usd
CY2022	us-gaap	Interest Expense Federal Home Loan Bank And Federal Reserve Bank Advances Long Term InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm	3052000	usd
CY2024	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	1942000	usd
CY2023	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	1942000	usd
CY2022	us-gaap	Interest Expense Subordinated Notes And Debentures InterestExpenseSubordinatedNotesAndDebentures	1942000	usd
CY2024	us-gaap	Interest Expense Operating InterestExpenseOperating	61732000	usd
CY2023	us-gaap	Interest Expense Operating InterestExpenseOperating	43889000	usd
CY2022	us-gaap	Interest Expense Operating InterestExpenseOperating	14414000	usd
CY2024	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	123105000	usd
CY2023	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	123303000	usd
CY2022	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	104280000	usd
CY2024	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5511000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	4774000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6217000	usd
CY2024	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	117594000	usd
CY2023	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	118529000	usd
CY2022	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	98063000	usd
CY2024	us-gaap	Fee Income FeeIncome	10026000	usd
CY2023	us-gaap	Fee Income FeeIncome	11138000	usd
CY2022	us-gaap	Fee Income FeeIncome	8525000	usd
CY2024	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	8557000	usd
CY2023	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	6711000	usd
CY2022	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	7917000	usd
CY2024	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	8356000	usd
CY2023	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	0	usd
CY2022	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	0	usd
CY2024	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	-7836000	usd
CY2023	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	0	usd
CY2022	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	0	usd
CY2024	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	990000	usd
CY2023	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	920000	usd
CY2022	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	876000	usd
CY2024	us-gaap	Noninterest Income Other NoninterestIncomeOther	1463000	usd
CY2023	us-gaap	Noninterest Income Other NoninterestIncomeOther	1721000	usd
CY2022	us-gaap	Noninterest Income Other NoninterestIncomeOther	790000	usd
CY2024	us-gaap	Noninterest Income NoninterestIncome	21556000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	20490000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	18108000	usd
CY2024	us-gaap	Share Based Compensation ShareBasedCompensation	1806000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	2010000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	1971000	usd
CY2024	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2023000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-693000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-844000	usd
CY2024	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	990000	usd
CY2023	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	920000	usd
CY2022	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	876000	usd
CY2024	fsbw	Gain Loss On Sale Of Loans Held For Sale GainLossOnSaleOfLoansHeldForSale	8557000	usd
CY2023	fsbw	Gain Loss On Sale Of Loans Held For Sale GainLossOnSaleOfLoansHeldForSale	6711000	usd
CY2022	fsbw	Gain Loss On Sale Of Loans Held For Sale GainLossOnSaleOfLoansHeldForSale	7321000	usd
CY2024	fsbw	Gain Loss On Sale Of Portfolio Loans GainLossOnSaleOfPortfolioLoans	-0	usd
CY2023	fsbw	Gain Loss On Sale Of Portfolio Loans GainLossOnSaleOfPortfolioLoans	-0	usd
CY2022	fsbw	Gain Loss On Sale Of Portfolio Loans GainLossOnSaleOfPortfolioLoans	596000	usd
CY2024	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	8356000	usd
CY2023	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	-0	usd
CY2022	fsbw	Gain Loss On Disposition Of Mortgage Servicing Rights Msr GainLossOnDispositionOfMortgageServicingRightsMsr	-0	usd
CY2024	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-7836000	usd
CY2023	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-0	usd
CY2022	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-0	usd
CY2024	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	535623000	usd
CY2023	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	377144000	usd
CY2022	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	566898000	usd
CY2024	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	571287000	usd
CY2023	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	411484000	usd
CY2022	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	708400000	usd
CY2024	fsbw	Gain Loss On Purchase Of Tax Credits GainLossOnPurchaseOfTaxCredits	2277000	usd
CY2023	fsbw	Gain Loss On Purchase Of Tax Credits GainLossOnPurchaseOfTaxCredits	-0	usd
CY2022	fsbw	Gain Loss On Purchase Of Tax Credits GainLossOnPurchaseOfTaxCredits	-0	usd
CY2024	fsbw	Payments To Acquire Tax Credits PaymentsToAcquireTaxCredits	26217000	usd
CY2023	fsbw	Payments To Acquire Tax Credits PaymentsToAcquireTaxCredits	-0	usd
CY2022	fsbw	Payments To Acquire Tax Credits PaymentsToAcquireTaxCredits	-0	usd
CY2024	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-38000	usd
CY2023	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	48000	usd
CY2022	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-1000	usd
CY2024	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-0	usd
CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	148000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-0	usd
CY2024	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-124000	usd
CY2023	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	2331000	usd
CY2022	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	3550000	usd
CY2024	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-8051000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	4495000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-2127000	usd
CY2024	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-5301000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	3093000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	2616000	usd
CY2024	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	50823000	usd
CY2023	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	77669000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	184898000	usd
CY2024	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	101907000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2024	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	17716000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	17295000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	21201000	usd
CY2024	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	110340000	usd
CY2023	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	76030000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	22968000	usd
CY2024	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	-0	usd
CY2023	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	-0	usd
CY2022	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	1000000	usd
CY2024	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	25148000	usd
CY2023	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	4186000	usd
CY2022	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	5830000	usd
CY2024	us-gaap	Payments To Acquire Restricted Certificates Of Deposit PaymentsToAcquireRestrictedCertificatesOfDeposit	2708000	usd
CY2023	us-gaap	Payments To Acquire Restricted Certificates Of Deposit PaymentsToAcquireRestrictedCertificatesOfDeposit	23641000	usd
CY2022	us-gaap	Payments To Acquire Restricted Certificates Of Deposit PaymentsToAcquireRestrictedCertificatesOfDeposit	-0	usd
CY2024	fsbw	Payments For Origination Of Loans And Principle Collections Net PaymentsForOriginationOfLoansAndPrincipleCollectionsNet	73841000	usd
CY2023	fsbw	Payments For Origination Of Loans And Principle Collections Net PaymentsForOriginationOfLoansAndPrincipleCollectionsNet	185024000	usd
CY2022	fsbw	Payments For Origination Of Loans And Principle Collections Net PaymentsForOriginationOfLoansAndPrincipleCollectionsNet	534335000	usd
CY2024	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	0	usd
CY2023	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	336157000	usd
CY2022	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	0	usd
CY2024	us-gaap	Proceeds From Sale Of Mortgage Servicing Rights Msr ProceedsFromSaleOfMortgageServicingRightsMSR	16309000	usd
CY2023	us-gaap	Proceeds From Sale Of Mortgage Servicing Rights Msr ProceedsFromSaleOfMortgageServicingRightsMSR	0	usd
CY2022	us-gaap	Proceeds From Sale Of Mortgage Servicing Rights Msr ProceedsFromSaleOfMortgageServicingRightsMSR	0	usd
CY2024	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	0	usd
CY2023	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	0	usd
CY2022	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	39034000	usd
CY2024	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	63427000	usd
CY2023	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	2818000	usd
CY2022	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	5736000	usd
CY2024	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	0	usd
CY2023	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	718000	usd
CY2022	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	145000	usd
CY2024	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1635000	usd
CY2023	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1671000	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1551000	usd
CY2024	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	181000	usd
CY2023	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	usd
CY2022	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1169000	usd
CY2024	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	13507000	usd
CY2023	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-8497000	usd
CY2022	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	5833000	usd
CY2024	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-104197000	usd
CY2023	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	77669000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-504044000	usd
CY2024	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-183025000	usd
CY2023	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-30704000	usd
CY2022	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	211935000	usd
CY2024	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	967769000	usd
CY2023	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	2164338000	usd
CY2022	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	3003617000	usd
CY2024	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	753709000	usd
CY2023	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	2257120000	usd
CY2022	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	2859617000	usd
CY2024	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	8265000	usd
CY2023	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7764000	usd
CY2022	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7096000	usd
CY2024	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	-1633000	usd
CY2023	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	-273000	usd
CY2022	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	568000	usd
CY2024	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	386000	usd
CY2023	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	355000	usd
CY2022	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	190000	usd
CY2024	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	1075000	usd
CY2023	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	1017000	usd
CY2022	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	503000	usd
CY2024	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	2508000	usd
CY2023	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	223000	usd
CY2022	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	15628000	usd
CY2024	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	19318000	usd
CY2023	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-131084000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	334092000	usd
CY2024	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-34056000	usd
CY2023	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	24254000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	14946000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	65691000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	41437000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	26491000	usd
CY2024Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	31635000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	65691000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	41437000	usd
CY2024	us-gaap	Interest Paid Net InterestPaidNet	63061000	usd
CY2023	us-gaap	Interest Paid Net InterestPaidNet	38744000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	10968000	usd
CY2024	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	2370000	usd
CY2023	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	10396000	usd
CY2022	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	4693000	usd
CY2024	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	6665000	usd
CY2023	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	6779000	usd
CY2022	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	-41849000	usd
CY2024	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	1188000	usd
CY2023	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-3814000	usd
CY2022	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	8857000	usd
CY2024	fsbw	Unrealized Gain Loss On Portfolio Loans Measured Under Fair Value Option UnrealizedGainLossOnPortfolioLoansMeasuredUnderFairValueOption	52000	usd
CY2023	fsbw	Unrealized Gain Loss On Portfolio Loans Measured Under Fair Value Option UnrealizedGainLossOnPortfolioLoansMeasuredUnderFairValueOption	447000	usd
CY2022	fsbw	Unrealized Gain Loss On Portfolio Loans Measured Under Fair Value Option UnrealizedGainLossOnPortfolioLoansMeasuredUnderFairValueOption	-1654000	usd
CY2024	fsbw	Retention Of Gross Mortgage Servicing Rights From Loan Sales RetentionOfGrossMortgageServicingRightsFromLoanSales	2415000	usd
CY2023	fsbw	Retention Of Gross Mortgage Servicing Rights From Loan Sales RetentionOfGrossMortgageServicingRightsFromLoanSales	2772000	usd
CY2022	fsbw	Retention Of Gross Mortgage Servicing Rights From Loan Sales RetentionOfGrossMortgageServicingRightsFromLoanSales	5400000	usd
CY2024	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	usd
CY2023	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	usd
CY2022	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	145000	usd
CY2024	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	usd
CY2023	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	usd
CY2022	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	570000	usd
CY2024	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	422000	usd
CY2023	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	2034000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3049000	usd
CY2024	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	usd
CY2023	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	87512000	usd
CY2022	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	usd
CY2024	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	usd
CY2023	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	424949000	usd
CY2022	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	usd
CY2024Q4	fsbw	Number Of Bank Branches NumberOfBankBranches	27	pure
CY2024Q4	us-gaap	Cash Uninsured Amount CashUninsuredAmount	41000	usd
CY2023Q4	us-gaap	Cash Uninsured Amount CashUninsuredAmount	27000	usd
CY2024Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	15600000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2100000	usd
CY2024	fsbw	Fhlb Impairment FhlbImpairment	0	usd
CY2024	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1300000	usd
CY2023	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1300000	usd
CY2022	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	897000	usd
CY2024	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	310272000	usd
CY2024Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	471000	usd
CY2024Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	29568000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	281175000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	8500000	usd
CY2024Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	0	usd
CY2024Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	356000	usd
CY2024Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	8144000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Excluding Accrued Interest Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityExcludingAccruedInterestAmortizedCostBeforeAllowanceForCreditLoss	318772000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Gain DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedGain	471000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedLoss	29924000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Fair Value Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityFairValueExcludingAccruedInterest	289319000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	328695000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	939000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	36701000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	292933000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	8500000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	0	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	834000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	7666000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Excluding Accrued Interest Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityExcludingAccruedInterestAmortizedCostBeforeAllowanceForCreditLoss	337195000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Gain DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedGain	939000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedLoss	37535000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Fair Value Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityFairValueExcludingAccruedInterest	300599000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	31000	usd
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2024	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal	0	usd
CY2023	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal	14000	usd
CY2022	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityExcludingAccruedInterestCreditLossExpenseReversal	-41000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	45000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	31000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestBeforeAllowanceForCreditLoss	116000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1200000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1500000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	8500000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	8500000	usd
CY2024Q4	us-gaap	Debt Securities Held To Maturity Nonaccrual DebtSecuritiesHeldToMaturityNonaccrual	0	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	43189000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	511000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	160221000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	29057000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	203410000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	29568000	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue1	0	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1	-0	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue1	8144000	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss1	356000	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Fair Value1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionFairValue1	8144000	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Accumulated Loss1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionAccumulatedLoss1	356000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue	43189000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	511000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue	168365000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	29413000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Fair Value Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionFairValueTotal	211554000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Accumulated Loss Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionAccumulatedLossTotal	29924000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	58754000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	637000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	209362000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	36064000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	268116000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	36701000	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue1	0	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1	-0	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue1	7666000	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss1	834000	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Fair Value1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionFairValue1	7666000	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Accumulated Loss1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionAccumulatedLoss1	834000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue	58754000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	637000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue	217028000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	36898000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Fair Value Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionFairValueTotal	275782000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Accumulated Loss Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionAccumulatedLossTotal	37535000	usd
CY2024Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	0	pure
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	22	pure
CY2024Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	121	pure
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	30	pure
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	180	pure
CY2024	fsbw	Expected Credit Losses On Investments ExpectedCreditLossesOnInvestments	0	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	310272000	usd
CY2024Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	281175000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	328695000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	292933000	usd
CY2024Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	8500000	usd
CY2024Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	8144000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	8500000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	7666000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Excluding Accrued Interest Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityExcludingAccruedInterestAmortizedCostBeforeAllowanceForCreditLoss	318772000	usd
CY2024Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Fair Value Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityFairValueExcludingAccruedInterest	289319000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Excluding Accrued Interest Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityExcludingAccruedInterestAmortizedCostBeforeAllowanceForCreditLoss	337195000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Fair Value Excluding Accrued Interest DebtSecuritiesAvailableforsaleAndHeldtomaturityFairValueExcludingAccruedInterest	300599000	usd
CY2024	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	101907000	usd
CY2024	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	215000	usd
CY2024	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	8051000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2533821000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2433015000	usd
CY2024Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31870000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31534000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	2501951000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	2401481000	usd
CY2024Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-6000000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-8400000	usd
CY2024Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	2000000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	2600000	usd
CY2024Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	12200000	usd
CY2023Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	11500000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31534000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	5635000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	7135000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	1836000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	5299000	usd
CY2024Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31870000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	27992000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	5770000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	3476000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	1248000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	2228000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31534000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	25635000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	6623000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	2465000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	1058000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	1407000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	27992000	usd
CY2024Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	5300000	usd
CY2024	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2533821000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	13601000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2433015000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	10952000	usd
CY2024Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	463468000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	428075000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	534941000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	397889000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	236185000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	255975000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	215856000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	1432000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2533821000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff	382000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	1531000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	1761000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	728000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	696000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	1185000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	852000	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan Writeoff FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff	0	usd
CY2024	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	7135000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	491485000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	674717000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	464272000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	257540000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	134306000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	196511000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	213241000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	943000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2433015000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff	204000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	1435000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	673000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	290000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	152000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	592000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	130000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan Writeoff FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff	0	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	3476000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	5682000	usd
CY2024Q4	fsbw	Financing Receivable Excluding Accrued Interest Nonaccrual With Allowance FinancingReceivableExcludingAccruedInterestNonaccrualWithAllowance	7919000	usd
CY2024Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	13601000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	1357000	usd
CY2023Q4	fsbw	Financing Receivable Excluding Accrued Interest Nonaccrual With Allowance FinancingReceivableExcludingAccruedInterestNonaccrualWithAllowance	9595000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	10952000	usd
CY2024	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	427000	usd
CY2023	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	579000	usd
CY2022	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	506000	usd
CY2023Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	3343000	usd
CY2022Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	3445000	usd
CY2024	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	345000	usd
CY2023	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	0	usd
CY2024	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	113000	usd
CY2023	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	102000	usd
CY2024Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	3575000	usd
CY2023Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	3343000	usd
CY2024Q4	fsbw	Loans And Leases Receivable Commitment To Lend Related Party LoansAndLeasesReceivableCommitmentToLendRelatedParty	3600000	usd
CY2023Q4	fsbw	Loans And Leases Receivable Commitment To Lend Related Party LoansAndLeasesReceivableCommitmentToLendRelatedParty	3700000	usd
CY2024Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	57053000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	57574000	usd
CY2024Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	27297000	usd
CY2023Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	26996000	usd
CY2024Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	29756000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	30578000	usd
CY2024	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2500000	usd
CY2023	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2600000	usd
CY2022	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2500000	usd
CY2024	us-gaap	Operating Lease Cost OperatingLeaseCost	1896000	usd
CY2023	us-gaap	Operating Lease Cost OperatingLeaseCost	1837000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	1422000	usd
CY2024	us-gaap	Short Term Lease Cost ShortTermLeaseCost	10000	usd
CY2023	us-gaap	Short Term Lease Cost ShortTermLeaseCost	19000	usd
CY2022	us-gaap	Short Term Lease Cost ShortTermLeaseCost	21000	usd
CY2024	us-gaap	Lease Cost LeaseCost	1906000	usd
CY2023	us-gaap	Lease Cost LeaseCost	1856000	usd
CY2022	us-gaap	Lease Cost LeaseCost	1443000	usd
CY2024	us-gaap	Operating Lease Payments OperatingLeasePayments	1950000	usd
CY2023	us-gaap	Operating Lease Payments OperatingLeasePayments	1882000	usd
CY2024Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P3Y6M
CY2023Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y
CY2024Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0314	pure
CY2023Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0295	pure
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	1706000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	1572000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1273000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	531000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	402000	usd
CY2024Q4	fsbw	Lessee Operating Lease Liability To Be Paid After Year Four LesseeOperatingLeaseLiabilityToBePaidAfterYearFour	676000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	6160000	usd
CY2024Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	604000	usd
CY2024Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	5556000	usd
CY2023Q4	us-gaap	Other Real Estate OtherRealEstate	0	usd
CY2022Q4	us-gaap	Other Real Estate OtherRealEstate	570000	usd
CY2021Q4	us-gaap	Other Real Estate OtherRealEstate	0	usd
CY2024	us-gaap	Other Real Estate Additions OtherRealEstateAdditions	0	usd
CY2023	us-gaap	Other Real Estate Additions OtherRealEstateAdditions	0	usd
CY2022	us-gaap	Other Real Estate Additions OtherRealEstateAdditions	0	usd
CY2024	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	usd
CY2023	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	usd
CY2022	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	145000	usd
CY2024	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	usd
CY2023	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	usd
CY2022	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	570000	usd
CY2024	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	-0	usd
CY2023	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	718000	usd
CY2022	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	145000	usd
CY2024	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	0	usd
CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	148000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	0	usd
CY2024Q4	us-gaap	Other Real Estate OtherRealEstate	0	usd
CY2023Q4	us-gaap	Other Real Estate OtherRealEstate	0	usd
CY2022Q4	us-gaap	Other Real Estate OtherRealEstate	570000	usd
CY2024Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	627679000	usd
CY2023Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	654048000	usd
CY2024Q4	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	176561000	usd
CY2023Q4	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	244028000	usd
CY2024Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	154188000	usd
CY2023Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	151630000	usd
CY2024Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	341615000	usd
CY2023Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	359063000	usd
CY2024Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	440257000	usd
CY2023Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	587858000	usd
CY2024Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	455594000	usd
CY2023Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	429373000	usd
CY2024Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	133045000	usd
CY2023Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	79540000	usd
CY2024Q4	fsbw	Noninterestbearing Deposit Escrow For Mortgages Serviced NoninterestbearingDepositEscrowForMortgagesServiced	10479000	usd
CY2023Q4	fsbw	Noninterestbearing Deposit Escrow For Mortgages Serviced NoninterestbearingDepositEscrowForMortgagesServiced	16783000	usd
CY2024Q4	us-gaap	Deposits Deposits	2339418000	usd
CY2023Q4	us-gaap	Deposits Deposits	2522323000	usd
CY2024Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	869282000	usd
CY2024Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	127484000	usd
CY2024Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	20307000	usd
CY2024Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	11419000	usd
CY2024Q4	fsbw	Time Deposit Maturities Year Five And Thereafter TimeDepositMaturitiesYearFiveAndThereafter	404000	usd
CY2024Q4	us-gaap	Time Deposits TimeDeposits	1028896000	usd
CY2024	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	2521000	usd
CY2023	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	2586000	usd
CY2022	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	495000	usd
CY2024	fsbw	Interest Expense Money Market Accounts And Savings Deposits InterestExpenseMoneyMarketAccountsAndSavingsDeposits	7633000	usd
CY2023	fsbw	Interest Expense Money Market Accounts And Savings Deposits InterestExpenseMoneyMarketAccountsAndSavingsDeposits	5511000	usd
CY2022	fsbw	Interest Expense Money Market Accounts And Savings Deposits InterestExpenseMoneyMarketAccountsAndSavingsDeposits	3775000	usd
CY2024	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	43009000	usd
CY2023	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	28654000	usd
CY2022	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	5150000	usd
CY2024	us-gaap	Interest Expense Deposits InterestExpenseDeposits	53163000	usd
CY2023	us-gaap	Interest Expense Deposits InterestExpenseDeposits	36751000	usd
CY2022	us-gaap	Interest Expense Deposits InterestExpenseDeposits	9420000	usd
CY2024Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	3200000	usd
CY2023Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	2800000	usd
CY2024	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	1	pure
CY2024	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1900000	usd
CY2023	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1700000	usd
CY2022	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1900000	usd
CY2024	fsbw	Federal Home Loan Bank Advances General Debt Obligations Maximum Amount Available Percentage Of Total Assets FederalHomeLoanBankAdvancesGeneralDebtObligationsMaximumAmountAvailablePercentageOfTotalAssets	0.45	pure
CY2024Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	1110000000	usd
CY2024Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Maximum Amount Available FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable	649700000	usd
CY2024Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Amount Of Available Unused Funds FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds	349500000	usd
CY2024Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	299806000	usd
CY2023Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	3896000	usd
CY2024Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	307806000	usd
CY2023Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	93746000	usd
CY2024Q4	fsbw	Debt Maturity Year One DebtMaturityYearOne	259000000	usd
CY2024Q4	fsbw	Debt Maturity Year One Interest Rate DebtMaturityYearOneInterestRate	0.046	pure
CY2024Q4	fsbw	Debt Maturity Year Two DebtMaturityYearTwo	48806000	usd
CY2024Q4	fsbw	Debt Maturity Year Two Interest Rate DebtMaturityYearTwoInterestRate	0.0479	pure
CY2024Q4	fsbw	Debt Maturity Total DebtMaturityTotal	307806000	usd
CY2024Q4	fsbw	Debt Maturity Interest Rate DebtMaturityInterestRate	0.0463	pure
CY2024Q4	us-gaap	Federal Home Loan Bank Advances Activity For Year Maximum Outstanding At Any Month End FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd	299805000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Activity For Year Maximum Outstanding At Any Month End FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd	74895000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Activity For Year Maximum Outstanding At Any Month End FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd	260828000	usd
CY2024	us-gaap	Line Of Credit Facility Maximum Monthend Outstanding Amount LineOfCreditFacilityMaximumMonthendOutstandingAmount	3963000	usd
CY2023	us-gaap	Line Of Credit Facility Maximum Monthend Outstanding Amount LineOfCreditFacilityMaximumMonthendOutstandingAmount	0	usd
CY2022	us-gaap	Line Of Credit Facility Maximum Monthend Outstanding Amount LineOfCreditFacilityMaximumMonthendOutstandingAmount	0	usd
CY2024	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	122015000	usd
CY2023	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	33945000	usd
CY2022	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	102008000	usd
CY2024	us-gaap	Line Of Credit Facility Average Outstanding Amount LineOfCreditFacilityAverageOutstandingAmount	11000	usd
CY2023	us-gaap	Line Of Credit Facility Average Outstanding Amount LineOfCreditFacilityAverageOutstandingAmount	11000	usd
CY2022	us-gaap	Line Of Credit Facility Average Outstanding Amount LineOfCreditFacilityAverageOutstandingAmount	15000	usd
CY2024	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0503	pure
CY2023	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.044	pure
CY2022	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0298	pure
CY2024	us-gaap	Line Of Credit Facility Interest Rate During Period LineOfCreditFacilityInterestRateDuringPeriod	0.0588	pure
CY2023	us-gaap	Line Of Credit Facility Interest Rate During Period LineOfCreditFacilityInterestRateDuringPeriod	0.0562	pure
CY2022	us-gaap	Line Of Credit Facility Interest Rate During Period LineOfCreditFacilityInterestRateDuringPeriod	0.0328	pure
CY2024	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	8580000	usd
CY2023	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	9912000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	8183000	usd
CY2024	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2023000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-693000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-844000	usd
CY2024	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6557000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2024	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	8744000	usd
CY2024	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21	pure
CY2023	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9507000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21	pure
CY2022	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	7767000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21	pure
CY2024	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	179000	usd
CY2024	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.004	pure
CY2023	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	333000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.007	pure
CY2022	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	852000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.023	pure
CY2024	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	160000	usd
CY2024	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.004	pure
CY2023	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	165000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.004	pure
CY2022	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	31000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0.001	pure
CY2024	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	180000	usd
CY2024	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.004	pure
CY2023	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	36000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.001	pure
CY2022	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	274000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.007	pure
CY2024	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Amount EffectiveIncomeTaxRateReconciliationEquityCompensationAmount	631000	usd
CY2024	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Percent EffectiveIncomeTaxRateReconciliationEquityCompensationPercent	0.015	pure
CY2023	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Amount EffectiveIncomeTaxRateReconciliationEquityCompensationAmount	208000	usd
CY2023	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Percent EffectiveIncomeTaxRateReconciliationEquityCompensationPercent	0.005	pure
CY2022	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Amount EffectiveIncomeTaxRateReconciliationEquityCompensationAmount	146000	usd
CY2022	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Percent EffectiveIncomeTaxRateReconciliationEquityCompensationPercent	0.004	pure
CY2024	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Amount EffectiveIncomeTaxRateReconciliationExecutiveCompensationAmount	560000	usd
CY2024	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Percent EffectiveIncomeTaxRateReconciliationExecutiveCompensationPercent	0.013	pure
CY2023	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Amount EffectiveIncomeTaxRateReconciliationExecutiveCompensationAmount	52000	usd
CY2023	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Percent EffectiveIncomeTaxRateReconciliationExecutiveCompensationPercent	0.001	pure
CY2022	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Amount EffectiveIncomeTaxRateReconciliationExecutiveCompensationAmount	265000	usd
CY2022	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Percent EffectiveIncomeTaxRateReconciliationExecutiveCompensationPercent	0.007	pure
CY2024	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	2277000	usd
CY2024	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.055	pure
CY2023	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	-0	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0	pure
CY2022	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	-0	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0	pure
CY2024	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6557000	usd
CY2024	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.157	pure
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2023	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.204	pure
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.198	pure
CY2024Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	6859000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	6746000	usd
CY2024Q4	fsbw	Deferred Tax Assets Nonaccrued Loan Interest DeferredTaxAssetsNonaccruedLoanInterest	42000	usd
CY2023Q4	fsbw	Deferred Tax Assets Nonaccrued Loan Interest DeferredTaxAssetsNonaccruedLoanInterest	3000	usd
CY2024Q4	fsbw	Deferred Tax Assets Lease Liability DeferredTaxAssetsLeaseLiability	1194000	usd
CY2023Q4	fsbw	Deferred Tax Assets Lease Liability DeferredTaxAssetsLeaseLiability	1463000	usd
CY2024Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	6256000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	7689000	usd
CY2024Q4	fsbw	Deferred Tax Assets Unfunded Commitments DeferredTaxAssetsUnfundedCommitments	302000	usd
CY2023Q4	fsbw	Deferred Tax Assets Unfunded Commitments DeferredTaxAssetsUnfundedCommitments	327000	usd
CY2024Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	36000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	49000	usd
CY2024Q4	fsbw	Deferred Tax Assets Purchase Accounting Adjustments DeferredTaxAssetsPurchaseAccountingAdjustments	481000	usd
CY2023Q4	fsbw	Deferred Tax Assets Purchase Accounting Adjustments DeferredTaxAssetsPurchaseAccountingAdjustments	48000	usd
CY2024Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	15764000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	17053000	usd
CY2024Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	2513000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	2512000	usd
CY2024Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	1960000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	3679000	usd
CY2024Q4	fsbw	Deferred Tax Liabilities Stock Dividends Fhlb Stock DeferredTaxLiabilitiesStockDividendsFhlbStock	-0	usd
CY2023Q4	fsbw	Deferred Tax Liabilities Stock Dividends Fhlb Stock DeferredTaxLiabilitiesStockDividendsFhlbStock	7000	usd
CY2024Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	1515000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	1408000	usd
CY2024Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1156000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1415000	usd
CY2024Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	1561000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	1307000	usd
CY2024Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	8705000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	10328000	usd
CY2024Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	7059000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	6725000	usd
CY2024Q4	us-gaap	Liability For Uncertain Tax Positions Current LiabilityForUncertainTaxPositionsCurrent	0	usd
CY2024	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	usd
CY2024Q4	us-gaap	Banking Regulation Capital Conservation Buffer Capital Conserved Minimum BankingRegulationCapitalConservationBufferCapitalConservedMinimum	0.025	pure
CY2024	us-gaap	Net Income Loss NetIncomeLoss	35024000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2024	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	572000	usd
CY2023	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	578000	usd
CY2022	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	554000	usd
CY2024	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	34452000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	35475000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	29095000	usd
CY2024	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7697806
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7656526
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7754507
CY2024	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	195440
CY2023	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	118907
CY2022	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	119133
CY2024	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	7893246
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	7775433
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	7873640
CY2024	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.48
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.63
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.75
CY2024	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.36
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.56
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.7
CY2024	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	11640
CY2023	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	56520
CY2022	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	61912
CY2024Q4	fsbw	Number Of Bank Branches NumberOfBankBranches	27	pure
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	45272000	usd
CY2022	fsbw	Overhead Costs Allocation OverheadCostsAllocation	23120000	usd
CY2024Q4	us-gaap	Goodwill Goodwill	3600000	usd
CY2024	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3500000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	691000	usd

Files In Submission

Name	View Source	Status
0001437749-25-008049-index-headers.html	Edgar Link	pending
0001437749-25-008049-index.html	Edgar Link	pending
0001437749-25-008049.txt	Edgar Link	pending
0001437749-25-008049-xbrl.zip	Edgar Link	pending
ex_745653.htm	Edgar Link	pending
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Financial_Report.xlsx	Edgar Link	pending
fsbw-20241231.xsd	Edgar Link	pending
fsbw20241231_10k.htm	Edgar Link	pending
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FilingSummary.xml	Edgar Link	unprocessable
fsbw-20241231_def.xml	Edgar Link	unprocessable
fsbw-20241231_cal.xml	Edgar Link	unprocessable
fsbw-20241231_lab.xml	Edgar Link	unprocessable
fsbw-20241231_pre.xml	Edgar Link	unprocessable
fsbw20241231_10k_htm.xml	Edgar Link	completed
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$FSBW
FS Bancorp, Inc. Stock $fsbw

2025 Q1 Form 10-K Financial Statement

#000143774925008049 Filed on March 17, 2025

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSBW FS Bancorp, Inc. Stock $fsbw

2025 Q1 Form 10-K Financial Statement

#000143774925008049 Filed on March 17, 2025

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSBW
FS Bancorp, Inc. Stock $fsbw