$FSBW
FS Bancorp, Inc. Stock $fsbw

$fsbw Overview Financials Valuation SEC Filings Company Website

2024 Q1 Form 10-K Financial Statement

#000143774924008140 Filed on March 15, 2024

Income Statement

Concept	2024 Q1	2023 Q4	2023
Revenue	$1.127M		$4.612M
YoY Change	23.3%		44.8%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin	$3.008M		$13.07M
YoY Change	11.74%		21.66%
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$2.835M	$3.149M	$2.600M
YoY Change	-15.57%	-11.05%	4.0%
% of Gross Profit
Operating Expenses	$3.008M		$13.07M
YoY Change	11.74%		21.66%
Operating Profit
YoY Change
Interest Expense	$14.53M		$43.89M
YoY Change	82.82%		204.49%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$10.53M	$12.08M	$45.27M
YoY Change	2.73%	26.27%	22.4%
Income Tax	$2.132M	$2.304M	$9.219M
% Of Pretax Income	20.25%	19.08%	20.36%
Net Earnings	$8.397M	$9.617M	$36.05M
YoY Change	2.25%	28.54%	21.6%
Net Earnings / Revenue	745.08%		781.72%
Basic Earnings Per Share	$1.07		$4.63
Diluted Earnings Per Share	$1.06	$1.23	$4.56
COMMON SHARES
Basic Shares Outstanding	7.806M	7.798M	7.657M
Diluted Shares Outstanding	7.824M		7.775M

Balance Sheet

Concept	2024 Q1	2023 Q4	2023
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$45.41M	$65.69M
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	$30.33M	$30.58M	$37.21M
YoY Change	-22.63%	21.73%	18.7%
Goodwill	$3.592M	$3.600M
YoY Change	0.0%	55.71%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$4.832M	$14.81M	$14.81M
YoY Change	-17.54%	122.05%	122.05%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$2.970B	$2.973B	$2.973B
YoY Change	6.72%	12.9%	12.9%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$6.410M	$6.848M	$6.848M
YoY Change	-16.22%	5.78%	5.78%
Deferred Revenue
YoY Change
Short-Term Debt	$129.9M	$93.75M
YoY Change		-49.74%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$6.410M	$6.848M	$6.848M
YoY Change	-16.22%	5.78%	5.78%
LONG-TERM LIABILITIES
Long-Term Debt	$49.54M	$49.53M	$49.53M
YoY Change	0.14%	0.13%	0.13%
Other Long-Term Liabilities	$40.58M	$35.74M	$35.74M
YoY Change	22.81%	15.29%	15.29%
Total Long-Term Liabilities	$90.13M	$85.26M	$85.26M
YoY Change	9.21%	5.97%	5.97%
TOTAL LIABILITIES
Total Short-Term Liabilities	$6.410M	$6.848M	$6.848M
Total Long-Term Liabilities	$90.13M	$85.26M	$85.26M
Total Liabilities	$2.692B	$2.708B	$2.708B
YoY Change	5.93%	12.78%	12.78%
SHAREHOLDERS EQUITY
Retained Earnings	$236.7M	$230.4M
YoY Change	13.62%	14.0%
Common Stock	$78.00K	$78.00K
YoY Change	-99.86%	-99.86%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$277.9M	$264.5M	$264.5M
YoY Change
Total Liabilities & Shareholders Equity	$2.970B	$2.973B	$2.973B
YoY Change	6.72%	12.9%	12.9%

Cashflow Statement

Concept	2024 Q1	2023 Q4	2023
OPERATING ACTIVITIES
Net Income	$8.397M	$9.617M	$36.05M
YoY Change	2.25%	28.54%	21.6%
Depreciation, Depletion And Amortization	$2.835M	$3.149M	$2.600M
YoY Change	-15.57%	-11.05%	4.0%
Cash From Operating Activities	$277.0K	$12.67M	$77.67M
YoY Change	-98.5%	-39.53%	-57.99%
INVESTING ACTIVITIES
Capital Expenditures	$357.0K	$271.0K	$1.671M
YoY Change	-62.58%	-68.34%	7.74%
Acquisitions
YoY Change
Other Investing Activities	$2.920M	-$64.56M	$79.34M
YoY Change	-98.99%	-40.16%	-115.79%
Cash From Investing Activities	$2.563M	-$64.83M	$77.67M
YoY Change	-99.11%	-40.38%	-115.41%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$223.0K
YoY Change			-98.57%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-$23.13M	37.22M	-$131.1M
YoY Change	-92.03%	-221.74%	-139.24%
NET CHANGE
Cash From Operating Activities	$277.0K	12.67M	$77.67M
Cash From Investing Activities	$2.563M	-64.83M	$77.67M
Cash From Financing Activities	-$23.13M	37.22M	-$131.1M
Net Change In Cash	-$20.29M	-14.95M	$24.25M
YoY Change	-221.15%	-87.37%	62.28%
FREE CASH FLOW
Cash From Operating Activities	$277.0K	$12.67M	$77.67M
Capital Expenditures	$357.0K	$271.0K	$1.671M
Free Cash Flow	-$80.00K	$12.40M	$76.00M
YoY Change	-100.46%	-38.31%	-58.55%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2023	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2023	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2023	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2023
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CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	31000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	7666000	usd
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CY2023Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	15088000	usd
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CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.56
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CY2023	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	2	pure
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CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
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CY2023Q4	us-gaap	Debt Securities Held To Maturity90 Days Or More Past Due Still Accruing DebtSecuritiesHeldToMaturity90DaysOrMorePastDueStillAccruing	0	usd
CY2022	fsbw	Other Than Temporary Impairment On Investments OtherThanTemporaryImpairmentOnInvestments	0	usd
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CY2023	dei	Document Type DocumentType	10-K
CY2023	dei	Document Annual Report DocumentAnnualReport	true
CY2023	dei	Document Period End Date DocumentPeriodEndDate	2023-12-31
CY2023	dei	Document Transition Report DocumentTransitionReport	false
CY2023	dei	Entity File Number EntityFileNumber	001-35589
CY2023	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	WA
CY2023	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	45-4585178
CY2023	dei	Entity Address Address Line1 EntityAddressAddressLine1	6920 220th Street SW
CY2023	dei	Entity Address City Or Town EntityAddressCityOrTown	Mountlake Terrace
CY2023	dei	Entity Address State Or Province EntityAddressStateOrProvince	WA
CY2023	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	98043
CY2023	dei	City Area Code CityAreaCode	425
CY2023	dei	Local Phone Number LocalPhoneNumber	771-5299
CY2023	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value per share
CY2023	dei	Trading Symbol TradingSymbol	FSBW
CY2023	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2023	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2023	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
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CY2023	dei	Auditor Name AuditorName	Moss Adams LLP
CY2023	dei	Auditor Location AuditorLocation	Everett, Washington
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CY2023	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	123303000	usd
CY2022	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	104280000	usd
CY2021	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	86649000	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
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	500000	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
CY2021	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	86149000	usd
CY2023	us-gaap	Fee Income FeeIncome	11138000	usd
CY2022	us-gaap	Fee Income FeeIncome	8525000	usd
CY2021	us-gaap	Fee Income FeeIncome	4349000	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
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	31083000	usd
CY2023	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	920000	usd
CY2022	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	876000	usd
CY2021	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	866000	usd
CY2023	us-gaap	Noninterest Income Other NoninterestIncomeOther	1721000	usd
CY2022	us-gaap	Noninterest Income Other NoninterestIncomeOther	790000	usd
CY2021	us-gaap	Noninterest Income Other NoninterestIncomeOther	1215000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	20490000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	18108000	usd
CY2021	us-gaap	Noninterest Income NoninterestIncome	37513000	usd
CY2023	us-gaap	Labor And Related Expense LaborAndRelatedExpense	53622000	usd
CY2022	us-gaap	Labor And Related Expense LaborAndRelatedExpense	47632000	usd
CY2021	us-gaap	Labor And Related Expense LaborAndRelatedExpense	49721000	usd
CY2023	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	13070000	usd
CY2022	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	10743000	usd
CY2021	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	10791000	usd
CY2023	us-gaap	Occupancy Net OccupancyNet	6378000	usd
CY2022	us-gaap	Occupancy Net OccupancyNet	5165000	usd
CY2021	us-gaap	Occupancy Net OccupancyNet	4892000	usd
CY2023	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6852000	usd
CY2022	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6062000	usd
CY2021	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4951000	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
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-9000	usd
CY2023	us-gaap	Loan Processing Fee LoanProcessingFee	2574000	usd
CY2022	us-gaap	Loan Processing Fee LoanProcessingFee	2718000	usd
CY2021	us-gaap	Loan Processing Fee LoanProcessingFee	2795000	usd
CY2023	us-gaap	Professional Fees ProfessionalFees	2584000	usd
CY2022	us-gaap	Professional Fees ProfessionalFees	3154000	usd
CY2021	us-gaap	Professional Fees ProfessionalFees	3181000	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
CY2021	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	636000	usd
CY2023	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1349000	usd
CY2022	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	897000	usd
CY2021	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	634000	usd
CY2023	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	1562000	usd
CY2022	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	898000	usd
CY2021	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	0	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3464000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	691000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	691000	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
CY2021	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-2059000	usd
CY2023	us-gaap	Noninterest Expense NoninterestExpense	93747000	usd
CY2022	us-gaap	Noninterest Expense NoninterestExpense	79183000	usd
CY2021	us-gaap	Noninterest Expense NoninterestExpense	76242000	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
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	47420000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10008000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	usd
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.63
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.75
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.48
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.56
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.7
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.37
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	6779000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-41849000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-5150000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	1458000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-8998000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-1108000	usd
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
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	1706000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	355000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	2116000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	367000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	5465000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	970000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Before Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax	-538000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	1174000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	209000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	-116000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	2326000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-25884000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2281000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	38379000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	3765000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	35131000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	230007000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	usd
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	4602000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1446000	usd
CY2021	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2021	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	13961000	usd
CY2021	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	211000	usd
CY2021	fsbw	Stock Issued During Period Value Stock Options Exercised Net StockIssuedDuringPeriodValueStockOptionsExercisedNet	2076000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2281000	usd
CY2021	us-gaap	Stock Issued During Period Value Employee Stock Ownership Plan StockIssuedDuringPeriodValueEmployeeStockOwnershipPlan	1773000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	247507000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	247507000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2022	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	7096000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1971000	usd
CY2022	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	503000	usd
CY2022	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2022	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	15628000	usd
CY2022	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	190000	usd
CY2022	fsbw	Stock Issued During Period Value Stock Options Exercised Net StockIssuedDuringPeriodValueStockOptionsExercisedNet	-568000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-25884000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	231697000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	231697000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2023	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	7764000	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2010000	usd
CY2023	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	1017000	usd
CY2023	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2023	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	usd
CY2023	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	223000	usd
CY2023	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	355000	usd
CY2023	fsbw	Stock Issued During Period Value Stock Options Exercised Net StockIssuedDuringPeriodValueStockOptionsExercisedNet	273000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	2326000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	264488000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	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
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	500000	usd
CY2023	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	12649000	usd
CY2022	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	14004000	usd
CY2021	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	15183000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	2010000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	1971000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	1446000	usd
CY2023	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	0	usd
CY2022	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	0	usd
CY2021	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	1773000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-693000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-844000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1750000	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
CY2021	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	866000	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
CY2021	fsbw	Gain Loss On Sale Of Loans Held For Sale GainLossOnSaleOfLoansHeldForSale	30977000	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
CY2021	fsbw	Gain Loss On Sale Of Portfolio Loans GainLossOnSaleOfPortfolioLoans	106000	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
CY2021	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	1353636000	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
CY2021	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	1444305000	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
CY2021	us-gaap	Mortgage Servicing Rights Msr Impairment Recovery MortgageServicingRightsMSRImpairmentRecovery	-2059000	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
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-9000	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
CY2021	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	564000	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
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	3670000	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
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-1491000	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
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	109009000	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
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	29863000	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
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	130138000	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
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	-0	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
CY2021	us-gaap	Proceeds From Payments For In Interest Bearing Deposits In Banks ProceedsFromPaymentsForInInterestBearingDepositsInBanks	1736000	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
CY2021	us-gaap	Payments To Acquire Restricted Certificates Of Deposit PaymentsToAcquireRestrictedCertificatesOfDeposit	-0	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
CY2021	fsbw	Payments For Origination Of Loans And Principle Collections Net PaymentsForOriginationOfLoansAndPrincipleCollectionsNet	214133000	usd
CY2023	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	336157000	usd
CY2022	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	0	usd
CY2021	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	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
CY2021	us-gaap	Proceeds From Sale Of Loans Receivable ProceedsFromSaleOfLoansReceivable	2699000	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
CY2021	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	1618000	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
CY2021	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	81000	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
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1984000	usd
CY2023	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	usd
CY2022	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1169000	usd
CY2021	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	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
CY2021	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-2661000	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
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-310833000	usd
CY2023	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-30704000	usd
CY2022	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	211935000	usd
CY2021	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	241537000	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
CY2021	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	148907000	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
CY2021	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	272188000	usd
CY2023	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7764000	usd
CY2022	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7096000	usd
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	4602000	usd
CY2023	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	usd
CY2022	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	usd
CY2021	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	49333000	usd
CY2023	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	-0	usd
CY2022	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	-0	usd
CY2021	us-gaap	Repayments Of Subordinated Debt RepaymentsOfSubordinatedDebt	10000000	usd
CY2023	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	-273000	usd
CY2022	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	568000	usd
CY2021	fsbw	Proceeds Disbursements From Stock Options Exercised ProceedsDisbursementsFromStockOptionsExercised	-2076000	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
CY2021	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	211000	usd
CY2023	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	1017000	usd
CY2022	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	503000	usd
CY2021	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	0	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
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	13961000	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
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	136739000	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
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-65085000	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
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	91576000	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
CY2023	us-gaap	Interest Paid Net InterestPaidNet	38744000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	10968000	usd
CY2021	us-gaap	Interest Paid Net InterestPaidNet	8174000	usd
CY2023	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	10396000	usd
CY2022	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	4693000	usd
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	11083000	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
CY2021	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	-5150000	usd
CY2023	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-3814000	usd
CY2022	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	8857000	usd
CY2021	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	2244000	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
CY2021	fsbw	Retention Of Gross Mortgage Servicing Rights From Loan Sales RetentionOfGrossMortgageServicingRightsFromLoanSales	9760000	usd
CY2023	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	0	usd
CY2022	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	145000	usd
CY2021	us-gaap	Fair Value Of Assets Acquired FairValueOfAssetsAcquired	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
CY2021	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	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
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	979000	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
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	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
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	usd
CY2023Q4	fsbw	Number Of Bank Branches NumberOfBankBranches	27	pure
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.48
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.37
CY2023Q4	us-gaap	Cash Uninsured Amount CashUninsuredAmount	27000	usd
CY2022Q4	us-gaap	Cash Uninsured Amount CashUninsuredAmount	281000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	2100000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	10600000	usd
CY2023	fsbw	Fhlb Impairment FhlbImpairment	0	usd
CY2023	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1300000	usd
CY2022	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	897000	usd
CY2021	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	634000	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	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	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	292933000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	usd
CY2023Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	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 DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	45000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss	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	us-gaap	Debt Securities Available For Sale And Held To Maturity Fair Value DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue	300599000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Allowance For Credit Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityAllowanceForCreditLoss	45000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	271793000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	48000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	42589000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	229252000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	usd
CY2022Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	8500000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	0	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	571000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	7929000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	31000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Amortized Cost Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityAmortizedCostBeforeAllowanceForCreditLoss	280293000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Gain DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedGain	48000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Cumulative Unrecognized Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityCumulativeUnrecognizedLoss	43160000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Fair Value DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue	237181000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Allowance For Credit Loss DebtSecuritiesAvailableForSaleAndHeldToMaturityAllowanceForCreditLoss	31000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	31000	usd
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	usd
CY2023	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	14000	usd
CY2022	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-41000	usd
CY2023	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	usd
CY2022	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	usd
CY2023	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	usd
CY2022	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	45000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	31000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestBeforeAllowanceForCreditLoss	116000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1500000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1200000	usd
CY2023Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	8500000	usd
CY2022Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	8500000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Nonaccrual DebtSecuritiesHeldToMaturityNonaccrual	0	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 DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionFairValue	275782000	usd
CY2023Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Accumulated Loss Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionAccumulatedLossTotal	37535000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	91176000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	10266000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	133700000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	32323000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	224876000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	42589000	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue1	7929000	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1	571000	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue1	0	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss1 DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss1	-0	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Fair Value1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionFairValue1	7929000	usd
CY2022Q4	fsbw	Debt Securities Heldtomaturity Unrealized Loss Position Accumulated Loss1 DebtSecuritiesHeldtomaturityUnrealizedLossPositionAccumulatedLoss1	571000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsFairValue	99105000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	10837000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue	133700000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	32323000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Fair Value DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionFairValue	232805000	usd
CY2022Q4	fsbw	Debt Securities Availableforsale And Heldtomaturity Continuous Unrealized Loss Position Accumulated Loss Total DebtSecuritiesAvailableforsaleAndHeldtomaturityContinuousUnrealizedLossPositionAccumulatedLossTotal	43160000	usd
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	0	pure
CY2023Q4	fsbw	Debt Securities Heldtomaturity Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	7	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
CY2023	fsbw	Other Than Temporary Impairment On Investments OtherThanTemporaryImpairmentOnInvestments	0	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	328695000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	292933000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	271793000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	229252000	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
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	8500000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	7929000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity DebtSecuritiesAvailableForSaleAndHeldToMaturity	337195000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Fair Value DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue	300599000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity DebtSecuritiesAvailableForSaleAndHeldToMaturity	280293000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity Fair Value DebtSecuritiesAvailableForSaleAndHeldToMaturityFairValue	237181000	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2023Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	2433015000	usd
CY2022Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	2218852000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	31534000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	27992000	usd
CY2023Q4	us-gaap	Notes Receivable Net NotesReceivableNet	2401481000	usd
CY2022Q4	us-gaap	Notes Receivable Net NotesReceivableNet	2190860000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-8400000	usd
CY2022Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-7800000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	2600000	usd
CY2022Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	-437000	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
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	26172000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	500000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	1793000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	756000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff After Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery	1037000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	25635000	usd
CY2021Q4	fsbw	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment	1163000	usd
CY2021Q4	fsbw	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment1	24472000	usd
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	25635000	usd
CY2021Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	5829000	usd
CY2021Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1748346000	usd
CY2021Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	1754175000	usd
CY2022Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	0	usd
CY2022	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	usd
CY2023Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	2433015000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	10952000	usd
CY2022Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	2218852000	usd
CY2022Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	8652000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	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
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	808060000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	550357000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	284645000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	164717000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	64940000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	166172000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	179462000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Converted To Term Loan FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan	499000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	2218852000	usd
CY2023Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	1357000	usd
CY2023Q4	fsbw	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	9595000	usd
CY2023Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	10952000	usd
CY2022Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	966000	usd
CY2022Q4	fsbw	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	7686000	usd
CY2022Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	8652000	usd
CY2023	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	579000	usd
CY2022	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	506000	usd
CY2021	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	351000	usd
CY2022Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	3445000	usd
CY2021Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	4207000	usd
CY2023	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	0	usd
CY2022	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	0	usd
CY2023	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	102000	usd
CY2022	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	762000	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
CY2023Q4	fsbw	Loans And Leases Receivable Commitment To Lend Related Party LoansAndLeasesReceivableCommitmentToLendRelatedParty	3700000	usd
CY2022Q4	fsbw	Loans And Leases Receivable Commitment To Lend Related Party LoansAndLeasesReceivableCommitmentToLendRelatedParty	3400000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	57574000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	49561000	usd
CY2023Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	26996000	usd
CY2022Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	24442000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	30578000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	25119000	usd
CY2023	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2600000	usd
CY2022	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2500000	usd
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	2700000	usd
CY2023	us-gaap	Operating Lease Cost OperatingLeaseCost	1837000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	1422000	usd
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	1433000	usd
CY2023	us-gaap	Short Term Lease Cost ShortTermLeaseCost	19000	usd
CY2022	us-gaap	Short Term Lease Cost ShortTermLeaseCost	21000	usd
CY2021	us-gaap	Short Term Lease Cost ShortTermLeaseCost	5000	usd
CY2023	us-gaap	Lease Cost LeaseCost	1856000	usd
CY2022	us-gaap	Lease Cost LeaseCost	1443000	usd
CY2021	us-gaap	Lease Cost LeaseCost	1438000	usd
CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	148000	usd
CY2023	us-gaap	Operating Lease Payments OperatingLeasePayments	1882000	usd
CY2022	us-gaap	Operating Lease Payments OperatingLeasePayments	1431000	usd
CY2023Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y7M6D
CY2023Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0295	pure
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0242	pure
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	1933000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	1628000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	1475000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1173000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	428000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	955000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	7592000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	744000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	6848000	usd
CY2022Q4	us-gaap	Other Real Estate OtherRealEstate	570000	usd
CY2021Q4	us-gaap	Other Real Estate OtherRealEstate	0	usd
CY2020Q4	us-gaap	Other Real Estate OtherRealEstate	90000	usd
CY2023	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	usd
CY2022	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	145000	usd
CY2021	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	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
CY2021	fsbw	Other Real Estate Additions Through Closed Retail Branch Transfer OtherRealEstateAdditionsThroughClosedRetailBranchTransfer	0	usd
CY2023	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	718000	usd
CY2022	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	145000	usd
CY2021	us-gaap	Other Real Estate Disposals OtherRealEstateDisposals	81000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	0	usd
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-9000	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
CY2023Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	654048000	usd
CY2022Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	537938000	usd
CY2023Q4	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	244028000	usd
CY2022Q4	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	135127000	usd
CY2023Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	151630000	usd
CY2022Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	134358000	usd
CY2023Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	359063000	usd
CY2022Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	574290000	usd
CY2023Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	587858000	usd
CY2022Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	440785000	usd
CY2023Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	429373000	usd
CY2022Q4	us-gaap	Time Deposits100000 Or More TimeDeposits100000OrMore	195447000	usd
CY2023Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	79540000	usd
CY2022Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	93560000	usd
CY2023Q4	fsbw	Noninterestbearing Deposit Escrow For Mortgages Serviced NoninterestbearingDepositEscrowForMortgagesServiced	16783000	usd
CY2022Q4	fsbw	Noninterestbearing Deposit Escrow For Mortgages Serviced NoninterestbearingDepositEscrowForMortgagesServiced	16236000	usd
CY2023Q4	us-gaap	Deposits Deposits	2522323000	usd
CY2022Q4	us-gaap	Deposits Deposits	2127741000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	863350000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	166827000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	44288000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	21727000	usd
CY2023Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	579000	usd
CY2023Q4	us-gaap	Time Deposits TimeDeposits	1096771000	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
CY2021	us-gaap	Line Of Credit Facility Maximum Monthend Outstanding Amount LineOfCreditFacilityMaximumMonthendOutstandingAmount	0	usd
CY2023	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	33945000	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
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	282000	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
CY2021	fsbw	Interest Expense Money Market Accounts And Savings Deposits InterestExpenseMoneyMarketAccountsAndSavingsDeposits	1604000	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
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	5043000	usd
CY2023	us-gaap	Interest Expense Deposits InterestExpenseDeposits	36751000	usd
CY2022	us-gaap	Interest Expense Deposits InterestExpenseDeposits	9420000	usd
CY2021	us-gaap	Interest Expense Deposits InterestExpenseDeposits	6929000	usd
CY2023Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	2800000	usd
CY2022Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	5700000	usd
CY2023	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	1	pure
CY2023	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1700000	usd
CY2022	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1900000	usd
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	1700000	usd
	fsbw	Federal Home Loan Bank Advances General Debt Obligations Maximum Amount Available Percentage Of Total Assets FederalHomeLoanBankAdvancesGeneralDebtObligationsMaximumAmountAvailablePercentageOfTotalAssets	0.45	pure
CY2023Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged1 FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1	1070000000.00	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Maximum Amount Available FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable	686200000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Amount Of Available Unused Funds FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds	681900000	usd
CY2023Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	3896000	usd
CY2022Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	186528000	usd
CY2023Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	93746000	usd
CY2022Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	186528000	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
CY2022	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	102008000	usd
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Activity For Year Maximum Outstanding At Any Month End FederalHomeLoanBankAdvancesActivityForYearMaximumOutstandingAtAnyMonthEnd	102528000	usd
CY2021	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	55602000	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
CY2021	us-gaap	Line Of Credit Facility Average Outstanding Amount LineOfCreditFacilityAverageOutstandingAmount	11000	usd
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
CY2021	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0188	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
CY2021	us-gaap	Line Of Credit Facility Interest Rate During Period LineOfCreditFacilityInterestRateDuringPeriod	0.0049	pure
CY2023	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	9912000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	8183000	usd
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	8258000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-693000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-844000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1750000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10008000	usd
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
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	9958000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21	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
CY2021	us-gaap	Income Tax Reconciliation Tax Exempt Income IncomeTaxReconciliationTaxExemptIncome	492000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	-0.01	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
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	28000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense EffectiveIncomeTaxRateReconciliationNondeductibleExpense	0	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
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	100000	usd
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.002	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
CY2021	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Amount EffectiveIncomeTaxRateReconciliationEquityCompensationAmount	883000	usd
CY2021	fsbw	Effective Income Tax Rate Reconciliation Equity Compensation Percent EffectiveIncomeTaxRateReconciliationEquityCompensationPercent	-0.019	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
CY2021	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Amount EffectiveIncomeTaxRateReconciliationExecutiveCompensationAmount	979000	usd
CY2021	fsbw	Effective Income Tax Rate Reconciliation Executive Compensation Percent EffectiveIncomeTaxRateReconciliationExecutiveCompensationPercent	0.021	pure
CY2023	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Amount EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanAmount	0	usd
CY2023	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Percent EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanPercent	0	pure
CY2022	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Amount EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanAmount	0	usd
CY2022	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Percent EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanPercent	0	pure
CY2021	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Amount EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanAmount	318000	usd
CY2021	fsbw	Effective Income Tax Rate Reconciliation Employee Stock Ownership Plan Percent EffectiveIncomeTaxRateReconciliationEmployeeStockOwnershipPlanPercent	0.007	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
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10008000	usd
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.211	pure
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	6746000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Allowance For Doubtful Accounts DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts	6119000	usd
CY2023Q4	fsbw	Deferred Tax Assets Nonaccrued Loan Interest DeferredTaxAssetsNonaccruedLoanInterest	3000	usd
CY2022Q4	fsbw	Deferred Tax Assets Nonaccrued Loan Interest DeferredTaxAssetsNonaccruedLoanInterest	11000	usd
CY2023Q4	fsbw	Deferred Tax Assets Lease Liability DeferredTaxAssetsLeaseLiability	1463000	usd
CY2022Q4	fsbw	Deferred Tax Assets Lease Liability DeferredTaxAssetsLeaseLiability	1392000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	7689000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	9146000	usd
CY2023Q4	fsbw	Deferred Tax Assets Unfunded Commitments DeferredTaxAssetsUnfundedCommitments	327000	usd
CY2022Q4	fsbw	Deferred Tax Assets Unfunded Commitments DeferredTaxAssetsUnfundedCommitments	547000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	49000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	234000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2023Q4	fsbw	Deferred Tax Assets Purchase Accounting Adjustments DeferredTaxAssetsPurchaseAccountingAdjustments	48000	usd
CY2022Q4	fsbw	Deferred Tax Assets Purchase Accounting Adjustments DeferredTaxAssetsPurchaseAccountingAdjustments	0	usd
CY2023Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	17053000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	17988000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	2512000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	2123000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	3679000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	3874000	usd
CY2023Q4	fsbw	Deferred Tax Liabilities Stock Dividends Fhlb Stock DeferredTaxLiabilitiesStockDividendsFhlbStock	7000	usd
CY2022Q4	fsbw	Deferred Tax Liabilities Stock Dividends Fhlb Stock DeferredTaxLiabilitiesStockDividendsFhlbStock	35000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	1408000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	1095000	usd
CY2023Q4	fsbw	Deferred Tax Liabilities Purchase Accounting Adjustments DeferredTaxLiabilitiesPurchaseAccountingAdjustments	-0	usd
CY2022Q4	fsbw	Deferred Tax Liabilities Purchase Accounting Adjustments DeferredTaxLiabilitiesPurchaseAccountingAdjustments	727000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1415000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	1338000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	1307000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	2126000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	10328000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	11318000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	6725000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	6670000	usd
CY2023Q4	us-gaap	Liability For Uncertain Tax Positions Current LiabilityForUncertainTaxPositionsCurrent	0	usd
CY2023	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	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
CY2021	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	611000	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
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	36801000	usd
CY2022	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	119133
CY2023Q4	us-gaap	Banking Regulation Capital Conservation Buffer Capital Conserved Minimum BankingRegulationCapitalConservationBufferCapitalConservedMinimum	0.025	pure
CY2023Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.09	pure
CY2023Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.105	pure
CY2023Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.137	pure
CY2023Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.105	pure
CY2022Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.097	pure
CY2022Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.107	pure
CY2022Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.14	pure
CY2022Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.107	pure
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7656526
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	7754507
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	8217916
CY2023	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	118907
CY2021	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	200580
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	7775433
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	7873640
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	8418496
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.63
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.75
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.48
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.56
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.7
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.37
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
CY2021	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	16466
CY2021Q3	us-gaap	Stockholders Equity Note Stock Split Conversion Ratio1 StockholdersEquityNoteStockSplitConversionRatio1	2	pure
CY2021Q3	us-gaap	Stockholders Equity Note Stock Split Conversion Ratio1 StockholdersEquityNoteStockSplitConversionRatio1	2	pure
CY2023Q4	fsbw	Number Of Bank Branches NumberOfBankBranches	27	pure
CY2023	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	123303000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	4774000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	20490000	usd
CY2023	us-gaap	Noninterest Expense NoninterestExpense	93747000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	45272000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	9219000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	36053000	usd
CY2023	us-gaap	Assets Average Outstanding AssetsAverageOutstanding	2843248000	usd
CY2023Q4	fsbw	Number Of Fulltime Employees Ft Es NumberOfFulltimeEmployeesFTEs	570	pure
CY2022	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	104280000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6217000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	18108000	usd
CY2022	us-gaap	Noninterest Expense NoninterestExpense	79183000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	36988000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7339000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	29649000	usd
CY2022	us-gaap	Assets Average Outstanding AssetsAverageOutstanding	2435694000	usd
CY2022Q4	fsbw	Number Of Fulltime Employees Ft Es NumberOfFulltimeEmployeesFTEs	537	pure
CY2021	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	86649000	usd
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	500000	usd
CY2021	us-gaap	Noninterest Income NoninterestIncome	37513000	usd
CY2021	us-gaap	Noninterest Expense NoninterestExpense	76242000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	47420000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10008000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	37412000	usd
CY2021	us-gaap	Assets Average Outstanding AssetsAverageOutstanding	2189213000	usd
CY2021Q4	fsbw	Number Of Fulltime Employees Ft Es NumberOfFulltimeEmployeesFTEs	536	pure
CY2023	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	4612000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3185000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3009000	usd
CY2023	us-gaap	Revenue Not From Contract With Customer Excluding Interest Income RevenueNotFromContractWithCustomerExcludingInterestIncome	15878000	usd
CY2022	us-gaap	Revenue Not From Contract With Customer Excluding Interest Income RevenueNotFromContractWithCustomerExcludingInterestIncome	14923000	usd
CY2021	us-gaap	Revenue Not From Contract With Customer Excluding Interest Income RevenueNotFromContractWithCustomerExcludingInterestIncome	34504000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	20490000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	18108000	usd
CY2021	us-gaap	Noninterest Income NoninterestIncome	37513000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	3600000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	2300000	usd
CY2023	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
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	691000	usd

Files In Submission

Name	View Source	Status
0001437749-24-008140-index-headers.html	Edgar Link	pending
0001437749-24-008140-index.html	Edgar Link	pending
0001437749-24-008140.txt	Edgar Link	pending
0001437749-24-008140-xbrl.zip	Edgar Link	pending
ex_572245.htm	Edgar Link	pending
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ex_572250.htm	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
fsbw-20231231.xsd	Edgar Link	pending
fsbw20221231_10k.htm	Edgar Link	pending
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perf.jpg	Edgar Link	pending
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fsbw-20231231_cal.xml	Edgar Link	unprocessable
fsbw-20231231_def.xml	Edgar Link	unprocessable
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fsbw-20231231_pre.xml	Edgar Link	unprocessable
fsbw20221231_10k_htm.xml	Edgar Link	completed
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report.css	Edgar Link	pending
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FilingSummary.xml	Edgar Link	unprocessable

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$FSBW
FS Bancorp, Inc. Stock $fsbw

2024 Q1 Form 10-K Financial Statement

#000143774924008140 Filed on March 15, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSBW FS Bancorp, Inc. Stock $fsbw

2024 Q1 Form 10-K Financial Statement

#000143774924008140 Filed on March 15, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSBW
FS Bancorp, Inc. Stock $fsbw