Document And Entity Information
Servicing Asset at Amortized Cost [Table Text Block]
Note To Financial Statement Details Textual
Statistical Measurement [Axis]
Note 2 - Securities Available for Sale
Note 3 - Loans Receivable
Income tax expense
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 4 - Mortgage Servicing Rights
Mortgage Banking [Member]
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 5 - Deposits
Trading Arrangements, by Individual [Table]
Note 6 - Borrowings
Material Terms of Trading Arrangement [Text Block]
Note 7 - Regulatory Capital
Private Equity Funds [Member]
Note 8 - Commitments, Off-balance Sheet Arrangements, and Contingent Liabilities
Financial Instrument [Axis]
Note 9 - Derivative Financial Instruments
Investment in Debt and Equity Securities and Other Trading Assets [Text Block]
Note 10 - Earnings Per Share
Note 11 - Fair Value Measurements
Note 12 - Segment Reporting
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross unrealized losses
Minimum [Member]
Note 2 - Securities Available for Sale - Amortized Cost and Fair Values of Securities Available for Sale (Details)
Gross unrealized gains
Note 2 - Securities Available for Sale - Amortized Cost and Fair Value of Investment Securities by Contractual Maturity (Details)
Statistical Measurement [Domain]
Note 2 - Securities Available for Sale - Gross Unrealized Losses and Fair Value of Securities Available for Sale in Continuous Unrealized Loss Position (Details)
Maximum [Member]
Note 3 - Loans Receivable - Summary of Loans Receivable (Details)
Note 3 - Loans Receivable - Analysis of Past Due Loans (Details)
Note 3 - Loans Receivable - Activity in Allowance for Credit Losses (Details)
Unused Portion of Construction Loans [Member]
Represents unused portion of construction loans.
Note 3 - Loans Receivable - Components of Provision for Credit Losses (Details)
Note 3 - Loans Receivable - Collateral Dependent Loans (Details)
Note 3 - Loans Receivable - Credit Quality Indicators (Details)
Note 3 - Loans Receivable - Restructurings of Financing Receivables (Details)
Note 3 - Loans Receivable - Non-accrual Loans (Details)
Note 4 - Mortgage Servicing Rights - Mortgage Servicing Rights (Details)
Note 4 - Mortgage Servicing Rights - Future Amortization Expenses (Details)
Recoveries
Note 5 - Deposits - Maturities (Details)
Note 6 - Borrowings - Borrowing (Details)
Federal Home Loan Bank, Advances, Callable Option [Member]
Commitments To Extend Credit Under Amortizing Loans [Member]
Represents commitments to extend credit under amortizing loans.
Note 7 - Regulatory Capital - Actual and Required Capital Amount and Ratio (Details)
Note 8 - Commitments, Off-balance Sheet Arrangements, and Contingent Liabilities - Financial Instruments (Details)
Federal Home Loan Bank, Advances, Option [Axis]
Commitments To Extend Credit Under Home Equity Lines Of Credit [Member]
Represents commitments to extend credit under home equity lines of credit.
Note 9 - Derivative Financial Instruments - Interest Rate Swaps (Details)
Federal Home Loan Bank, Advances, Option [Domain]
Note 10 - Earnings Per Share - Earnings Per Share (Details)
Note 11 - Fair Value Measurements - Fair Value of Assets and Liabilities (Details)
Note 11 - Fair Value Measurements -Reconciliation for All Assets Measured at Fair Value Using Significant Unobservable Inputs (Details)
us-gaap_DebtSecuritiesAvailableForSaleRestricted
Debt Securities, Available-for-Sale, Restricted
Note 11 - Fair Value Measurements - Assets Recorded at Fair Value on Non-recurring Basis (Details)
Note 11 - Fair Value Measurements - Fair Value of Assets Measured on Recurring Basis, Unobservable Input Reconciliation (Details)
Note 11 - Fair Value Measurements - Carrying Amount and Fair Values of Financial Instruments (Details)
Note 12 - Segment Reporting - Segment Information (Details)
Notes To Financial Statements
Notes To Financial Statements [Abstract]
Debt Securities, Available-for-Sale [Table]
us-gaap_Dividends
Cash dividend
Compensation, payroll taxes, and other employee benefits
Prepaid expenses and other assets
Financial Instruments [Domain]
FHLB advances, rate
Cash dividend, price per share (in dollars per share)
Asset Pledged as Collateral [Member]
Weighted Average [Member]
us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet
Decrease in accrued interest receivable
us-gaap_SharesOutstanding
Balances (in shares)
Balances (in shares)
Segment Reporting [Text Block]
Fair value, 12 months or longer
Fair value, less than 12 months
Adjustments to reconcile net income to net cash provided by operating activities:
Preferred stock (par value $.01 per share) authorized - 50,000,000 shares at June 30, 2026 and at December 31, 2025, no shares issued
Banking Regulation, Regulatory Capital Requirement, Compliance [Table]
us-gaap_Liabilities
Total liabilities
Segment Reporting, Reconciliation of Revenue by Segment to Consolidated [Table Text Block]
Liabilities:
wsbf_AccruedInterestReceivableFairValueDisclosure
Accrued interest receivable
The fair value of interest due on receivables that have already been recorded to income.
wsbf_FederalHomeLoanBankAdvancesMaximumPercentageOfLoanCarryingValue
Federal Home Loan Bank Advances, Maximum Percentage of Loan Carrying Value
Represents the maximum percentage of loan carrying value for federal home loan bank advances.
Mortgage Derivative [Member]
Represents mortgage derivative.
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]
wsbf_FairValueTransfersIntoOutOfLevels12And3Amount
Fair Value, Transfers into (out of) Levels 1, 2 and 3, Amount
Amount of transfers between levels 1, 2 and 3 during the period.
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and shareholders’ equity
Consolidation Items [Axis]
Pledged Status [Domain]
Segment Reporting [Table]
Pledged Status [Axis]
Federal Home Loan Bank of Chicago [Member]
Stock based compensation
Real estate owned
Real estate owned
Amount of expense (income) recognized during the period for the foreclosure on real estate assets.
Consolidation Items [Domain]
Net change in short-term borrowings
Preferred stock, shares issued (in shares)
Preferred stock, shares authorized (in shares)
Pull Through Rate [Member]
Represents pull through rate.
Portion at Fair Value Measurement [Member]
Valuation Technique, Pricing Model [Member]
Represents pricing model for valuation technique.
Reported Value Measurement [Member]
Fair Value, by Balance Sheet Grouping [Table]
Preferred stock, par value (in dollars per share)
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
(Decrease) increase in cash and cash equivalents
State of Wisconsin (to total assets)
Represents actual capital state of Wisconsin.
State of Wisconsin (to total assets) Ratio
The percentage of actual capital levels as established in the State of Wisconsin.
State of Wisconsin (to total assets), For Capital Adequacy Purposes
The minimum amount of capital required for capital adequacy purposes under the regulatory framework (State of Wisconsin).
Estimate of Fair Value Measurement [Member]
Tier I capital (to risk weighted assets), Minimum Capital Adequacy with Capital Buffer
The minimum amount of Tier 1 Risk Based Capital required for minimum capital adequacy with capital buffer under the regulatory framework for prompt corrective action.
Common Equity Tier I capital (to risk weighted assets) Minimum Capital Adequacy with Capital Buffer
The minimum amount of Common Equity Tier 1 Risk Based Capital required for minimum capital adequacy with capital buffer under the regulatory framework for prompt corrective action.
us-gaap_ServicingAssetAtAmortizedValueFairValue
Servicing Asset at Amortized Cost, Fair Value
Total capital (to risk-weighted assets), Minimum Capital Adequacy with Capital Buffer Ratio
The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for minimum capital adequacy with capital buffer under the regulatory framework for prompt corrective action.
Common Equity Tier 1 capital (to risk-weighted assets) Ratio
Tier I capital (to risk weighted assets), Minimum Capital Adequacy with Capital Buffer Ratio
The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for minimum capital adequacy with capital buffer under the regulatory framework for prompt corrective action.
US Government-sponsored Enterprises Debt Securities [Member]
Total capital (to risk-weighted assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio
Schedule of Fair Value, off-Balance-Sheet Risks [Table Text Block]
us-gaap_ServicingAssetAtAmortizedValueDisposals
Sales
Total capital (to risk-weighted assets) Ratio
Additions
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents at beginning of period
Cash and cash equivalents at end of period
State of Wisconsin (to total assets), For Capital Adequacy Ratio
The percentage of capital adequacy levels as established in the State of Wisconsin.
Mortgage servicing rights at end of the period
Total capital (to risk-weighted assets), For Capital Adequacy Ratio
Total capital (to risk-weighted assets), Minimum Capital Adequacy with Capital Buffer
The minimum amount of capital adequacy with capital buffer required under the regulatory framework for prompt corrective action.
Consolidated Waterstone Financial Inc [Member]
Represents Consolidated Waterstone Financial Inc.
Tier I capital (to average assets) Ratio
wsbf_AmortizationOfEsopAwardNet
ESOP shares committed to be released to Plan participants
Net value of shares committed to be released under an Employee Stock Ownership Plan (ESOP).
Tier I capital (to risk-weighted assets), For Capital Adequacy Ratio
Tier I capital (to average assets), For Capital Adequacy Ratio
Statement [Table]
Servicing Asset at Amortized Cost [Table]
Tier I capital (to average assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio
Common Equity Tier I capital (to risk weighted), Minimum Capital Adequacy with Capital Buffer Ratio
The minimum Common Equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for minimum capital adequacy with capital buffer under the regulatory framework for prompt corrective action.
Valuation allowance recorded during the period
Reflects the estimated amount of impairment (recovery) as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.
Time deposits
Time Deposits
us-gaap_IncreaseDecreaseInDerivativeAssets
(Increase) decrease in derivative assets
Decrease (increase) in derivative liabilities
Common Equity Tier I capital (to risk-weighted), For Capital Adequacy Ratio
Common Equity Tier I capital (to risk-weighted) , To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio
Tier I capital (to risk-weighted assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio
Tier I capital (to risk-weighted assets) Ratio
Total unrealized loss
Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block]
us-gaap_LoansReceivableFairValueDisclosure
Loans receivable
wsbf_NumberOfStatesTheCompanyCanLendState
Number of States The Company Can Lend, State
Number of states in which the Company can lend in.
Total fair value
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
us-gaap_NotesPayableFairValueDisclosure
Borrowings
Derivatives liabilities, fair value
us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
FHLB stock
Financing Receivable, Allowance for Credit Loss [Table Text Block]
Mortgage Banking Segment [Member]
Represents information related to mortgage banking segment.
Multifamily [Member]
Financing Receivable, Past Due [Table Text Block]
Financing Receivable Credit Quality Indicators [Table Text Block]
us-gaap_LitigationReserve
Estimated Litigation Liability
Financing Receivable, Modified [Table Text Block]
Consolidated Entities [Axis]
Consolidated Entities [Domain]
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged
wsbf_IncreaseDecreaseInAccruedInterestOnDepositsAndBorrowings
Increase in accrued interest on deposits and borrowings
Represents increase (decrease) in accrued interest on deposits and borrowings.
Loans held for sale, at fair value
Asset Class [Axis]
Loans
Measurement Frequency [Axis]
Commitments and Contingencies Disclosure [Text Block]
Statement [Line Items]
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Net change in advance payments by borrowers for taxes
Common stock, shares outstanding (in shares)
Common stock, shares authorized (in shares)
Dividends declared but not paid in other liabilities
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Common stock (par value $.01 per share) authorized - 100,000,000 shares at June 30, 2026 and at December 31, 2025, issued and outstanding - 17,975,028 at June 30, 2026 and 18,359,717 at December 31, 2025
us-gaap_InterestPayableCurrentAndNoncurrent
Accrued interest payable
us-gaap_MortgageLoansInProcessOfForeclosureAmount
Mortgage Loans in Process of Foreclosure, Amount
Short-Term Debt, Type [Domain]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
Short-Term Debt, Type [Axis]
Federal funds sold
wsbf_NumberOfStatesMortgageBankingProductsAndServicesAreProvided
Number of States Mortgage Banking Products and Services are Provided
The number of states in which mortgage banking products and services are provided.
Total comprehensive income (loss)
Comprehensive income
Repurchase agreements, rate
Repurchase agreements
us-gaap_ShortTermBorrowings
Short-Term Debt
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds
Proceeds from long-term debt
FHLB long-term advances maturing 2031, rate
FHLB long-term advances maturing 2028, rate
us-gaap_FederalHomeLoanBankAdvancesLongTerm
Long-Term Federal Home Loan Bank Advances
Maturities of debt securities
FHLB long-term advances maturing 2027, rate
us-gaap_ServicingAssetAtAmortizedValueAmortization1
Amortization
FHLB long-term advances maturing 2030, rate
FHLB long-term advances maturing 2029, rate
us-gaap_DepositsFairValueDisclosure
Deposits
Debt securities, federal funds sold and short-term investments
Represents interest income federal funds sold and short-term investments.
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Mortgage derivative, net balance at the beginning of the period
Mortgage derivative, net balance at the end of the period
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
FHLB long-term advances maturing 2027
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate
Federal Home Loan Bank Advances [Member]
FHLB long-term advances maturing 2030
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate
FHLB long-term advances maturing 2029
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate
FHLB long-term advances maturing 2031
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromFourToFiveYearsOfBalanceSheetDate
Securities available for sale, cost
Amortized cost
FHLB long-term advances maturing 2028
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate
Federal Home Loan Bank stock, at cost
Standby Letters of Credit [Member]
Borrowings
Due after one year through five years, amortized cost
Payment Deferral [Member]
Other comprehensive (loss) income, net of tax:
Due after five years through ten years, amortized cost
Statement of Stockholders' Equity [Abstract]
Due within one year, amortized cost
Statement of Comprehensive Income [Abstract]
Loan Restructuring Modification [Axis]
Principal repayments on mortgage-related securities
Loan Restructuring Modification [Domain]
Proceeds on sales of loans originated for sale
Statement of Cash Flows [Abstract]
Contractual Interest Rate Reduction [Member]
Financing Receivable Portfolio Segment [Axis]
Due after five years through ten years, fair value
Due after ten years, fair value
Due within one year, fair value
Due after one year through five years, fair value
Due after ten years, amortized cost
Other comprehensive income
Total other comprehensive (loss) income
Shareholders’ equity:
FHLB short-term advances
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueInRemainderOfFiscalYear
Federal Home Loan Bank, Advance, Maturity, Remainder of Fiscal Year
us-gaap_LossContingencyEstimateOfPossibleLoss
Loss Contingency, Estimate of Possible Loss
Equity Components [Axis]
Unfunded Loan Commitment [Member]
Financing Receivable Portfolio Segment [Domain]
Home Equity Loan [Member]
Proceeds from stock option exercises
Equity Component [Domain]
Fair Value Measurements, Nonrecurring [Table Text Block]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Inputs, Level 1 [Member]
AOCI Attributable to Parent [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Corporate and Reconciling Items [Member]
Represents the aggregate total of non operating corporate items and reconciling items
Financial Instrument Performance Status [Domain]
Financial Asset, Aging [Axis]
Office properties and equipment, net
Financial Instrument Performance Status [Axis]
Financing Receivable, Nonaccrual [Table Text Block]
Forward Contracts [Member]
Financial Asset, Aging [Domain]
us-gaap_ProvisionForOtherCreditLosses
Investment securities, provision for credit losses
us-gaap_ProvisionForLoanLossesExpensed
Provision (credit) for credit losses - loans
Provision (credit) for credit losses
Provision (credit) for credit losses
Total, provision for credit losses
Stock compensation expense
Financial Asset, 60 to 89 Days Past Due [Member]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
ESOP shares committed to be released to plan participants
Fair Value Disclosures [Text Block]
Fair Value, by Balance Sheet Grouping [Table Text Block]
Supplemental information:
Derivatives Not Designated as Hedging Instruments [Table Text Block]
Loans held for sale
Mortgage banking income
Tier I capital (to risk-weighted assets), For Capital Adequacy Purposes
Other Commitments [Table]
us-gaap_PaymentsToAcquireLifeInsurancePolicies
Bank Owned Life Insurance
Tier I capital (to risk-weighted assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions
Tier I capital (to risk-weighted assets)
Accumulated other comprehensive loss, net of taxes
Tier I capital (to average assets), For Capital Adequacy Purposes
Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.
Tier I capital (to average assets)
More than two to three years
More than one to two years
More than three to four years
Within one year
More than four through five years
us-gaap_PaymentsToPurchaseLoansHeldForSale
Loans originated for sale
Basis of Accounting [Text Block]
us-gaap_PaymentsToAcquireMortgageBackedSecuritiesMBSCategorizedAsAvailableForSale
Mortgage related securities
Communications
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income before income taxes
Data processing
us-gaap_PaymentsToAcquireMarketableSecurities
Debt securities
Additional paid-in capital
Debt Disclosure [Text Block]
Total capital (to risk-weighted assets), For Capital Adequacy Purposes
Total capital (to risk-weighted assets)
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Premises and equipment
Stock compensation activity, net of tax
Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table]
us-gaap_NoninterestExpense
Total noninterest expenses
Noninterest expenses:
Restructured amount
Total borrowings, rate
us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
Stock compensation activity, net of tax
Financial Asset, Not Past Due [Member]
Schedule of Debt [Table Text Block]
Total capital (to risk-weighted assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions
Stock compensation activity, net of tax (in shares)
Debt Instrument, Name [Domain]
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
Stock compensation activity, net of tax (in shares)
us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Schedule of Long-Term Debt Instruments [Table]
Debt Instrument [Axis]
Operating activities:
Investing activities:
Debt Securities [Member]
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by (used in) operating activities
Financing activities:
Originated current year
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash (used in) provided by investing activities
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash (used in) provided by financing activities
Debt [Member]
Advance payments by borrowers for taxes
Advance payments by borrowers for taxes
us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Proceeds from Sale of Debt Securities, Available-for-Sale
Revolving
us-gaap_DepositLiabilityUninsured
Deposit Liability, Uninsured
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]
Net (decrease) increase in deposits
Advertising
Operating Segments [Member]
Accounting Policies [Abstract]
Segments [Domain]
us-gaap_IncreaseDecreaseInPrepaidTaxes
Increase in accrued taxes
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
US States and Political Subdivisions Debt Securities [Member]
Segments [Axis]
us-gaap_StockRepurchasedDuringPeriodValue
Purchase of common stock returned to authorized but unissued
us-gaap_StockRepurchasedDuringPeriodShares
Purchase of common stock returned to authorized but unissued (in shares)
Measurement Input Type [Axis]
Income Statement [Abstract]
wsbf_SecuritiesUnrealizedLossPositionNumberOfPositions
Securities, Unrealized Loss Position, Number of Positions
The number of securities in unrealized loss positions.
us-gaap_NumberOfOperatingSegments
Number of Operating Segments
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Deferred taxes
Measurement Input, Discount Rate [Member]
wsbf_UnearnedEsopSharesCost
Unearned ESOP shares
Cost of unearned shares that qualify as permanent equity that are held by an employee stock ownership plan (ESOP).
Net income
Net income
Total borrowings
us-gaap_DebtLongtermAndShorttermCombinedAmount
Financial Asset, Past Due [Member]
Measurement Input Type [Domain]
Multi-family Loan [Member]
Represents multi-family loan.
Net interest income
Net interest income
wsbf_FinancingReceivableTroubledDebtRestructuringSubsequentDefaultNumberOfContracts
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts
Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.
us-gaap_ProceedsFromSaleOfMortgageServicingRightsMSR
Proceeds from Sale of Mortgage Servicing Rights (MSR)
Unused lines of Credit [Member]
us-gaap_DerivativeAssetMeasurementInput
Mortgage banking derivatives, measurement input
FHLB advances
us-gaap_FederalHomeLoanBankAdvances
Federal Home Loan Bank, Advance
Number restructured
Number of financing receivables that have been modified by troubled debt restructurings.
Real estate owned measurement input
Accounting Standards Update and Change in Accounting Principle [Table]
Occupancy, office furniture, and equipment
us-gaap_OtherNoninterestExpense
Other
Loan processing expense
us-gaap_RelatedPartyDepositLiabilities
Related Party Deposit Liabilities
Increase in cash surrender value of life insurance
Increase in cash surrender value of life insurance
us-gaap_NoninterestIncome
Total noninterest income
Noninterest income:
Noninterest income:
us-gaap_PaymentsForProceedsFromLoansReceivable
Net (increase) decrease in loans receivable
Transfers and Servicing of Financial Assets [Text Block]
Service charges on loans and deposits
us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
Debt Securities, Available-for-Sale, Allowance for Credit Loss
wsbf_PaymentsForOriginationOfMortgageServicingRightsMsr
Origination of mortgage servicing rights
The cash outflow for origination of mortgage servicing rights.
Measurement Basis [Axis]
Interest-earning deposits in other financial institutions and other short term investments
For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, and other investments not otherwise specified in the taxonomy that will be realized in a short period of time, usually less than one year or the normal operating cycle, whichever is longer.
Unearned ESOP Shares [Member]
Represents unearned ESOP shares.
Other
Fair Value Hierarchy and NAV [Domain]
us-gaap_GainLossOnSalesOfLoansNet
Gain on sale of loans held for sale
Measurement Frequency [Domain]
us-gaap_RepaymentsOfLongTermDebt
Repayment of long-term debt
Statement of Financial Position [Abstract]
wsbf_NumberOfOffices
Number of Offices
The number of offices.
Deposit Liability [Table]
Mortgage derivative (loss) gain, net
Income tax payments
Mortgage-related Securities [Member]
Securities collateralized by mortgages.
Fair Value, Nonrecurring [Member]
Professional fees
Professional fees
Fair Value, Recurring [Member]
Common Equity Tier 1 Capital (to risk-weighted assets)
Common Equity Tier I capital (to risk weighted assets), For Capital Adequacy Purposes
us-gaap_PaymentsForRepurchaseOfCommonStock
Purchase of common stock returned to authorized but unissued
us-gaap_IncreaseDecreaseInOtherOperatingAssets
(Increase) decrease in other assets
Document Type
Originated one years before
Originated two years before
Document Information [Line Items]
Document Quarterly Report
Total Borrowing [Member]
Represents total borrowing.
Document Information [Table]
Common Equity Tier I capital (to risk-weighted assets), To Be Well-Capitalized Under Prompt Corrective Action Provisions
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)
Entity Interactive Data Current
Originated five years before
Document Transition Report
Diluted (in shares)
Diluted weighted average shares outstanding (in shares)
Originated three years before
Originated four years before
Income per share:
Effect of dilutive potential common shares (in shares)
Weighted average shares outstanding (in shares)
Basic (in shares)
Derivative Instrument [Axis]
us-gaap_NotesReceivableNet
Loans receivable, net
Basic earnings per share (in dollars per share)
Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table]
Demand deposits
Debt Securities, Available-for-Sale [Table Text Block]
FHLB short-term advances, rate
Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due in remainder of current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
us-gaap_Deposits
Total deposits
Deposit Liabilities Disclosures [Text Block]
Money market and savings deposits
Depreciation, amortization, accretion
Document Fiscal Period Focus
Pledging Purpose [Axis]
Document Fiscal Year Focus
Pledging Purpose [Domain]
Amendment Flag
Federal Home Loan Bank Branch [Domain]
Common Stock [Member]
Federal Home Loan Bank Branch [Axis]
Financing Receivable, Past Due [Table]
us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
Increase in other liabilities
us-gaap_PaymentsToAcquireFederalHomeLoanBankStock
FHLB stock
Sales of FHLB Stock
Document Period End Date
Residential Portfolio Segment [Member]
Legal Entity [Axis]
us-gaap_InterestAndDividendIncomeOperating
Total interest income
Consumer Portfolio Segment [Member]
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Table]
Commercial Portfolio Segment [Member]
Entity File Number
Entity Tax Identification Number
Non Accruing [Member]
Represents non accruing.
Unrealized loss, less than 12 months
Unrealized loss, 12 months or longer
Entity [Domain]
Entity Central Index Key
Financial Asset, 1 to 59 Days Past Due [Member]
Financial asset fewer than 60 days past due.
Less: Allowance for credit losses ("ACL") - loans
us-gaap_FinancingReceivableAllowanceForCreditLosses
Financing Receivable, Allowance for Credit Loss
Balance
Balance
Entity Registrant Name
Gross charge-offs, total
Charge-offs
Construction and Land Portfolio Segment [Member]
Portfolio segment of the company's total financing receivables related to construction and land.
Performing Financial Instruments [Member]
Entity Current Reporting Status
Substandard [Member]
Entity Incorporation, State or Country Code
Accruing [Member]
Represents accruing.
Pass [Member]
Current Fiscal Year End Date
One to Four Family [Member]
Represents one-to-four family.
Schedule of Allowance for Credit Losses [Table Text Block]
Tabular disclosure of allowance for credit losses.
Entity Filer Category
Entity Shell Company
Entity Emerging Growth Company
Derivatives notional amount
Nonperforming Financial Instruments [Member]
Entity Small Business
Schedule of Collateral Dependent Loans [Table Text Block]
Tabular disclosure of collateral dependent loans.
Valuation Approach and Technique [Axis]
Hedging Designation [Domain]
Cash
Derivatives Assets, fair value
Mortgage banking derivatives, fair value
Collateral Dependent Loans [Member]
Represents collateral dependent loans.
Financing Receivable, Modified [Table]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Interest expense:
us-gaap_InterestExpenseBorrowings
Borrowings
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Valuation Approach and Technique [Domain]
Valuation, Market Approach [Member]
Deposits
Entity Address, State or Province
Entity Address, City or Town
Retained earnings
us-gaap_InterestExpenseOperating
Total interest expense
Entity Address, Address Line One
City Area Code
Local Phone Number
Entity Address, Postal Zip Code
Derivative [Table]
Without single date securities, fair value
Title of 12(b) Security
Security Exchange Name
Trading Symbol
Without single date securities
Class of Stock [Axis]
Securities available for sale, at fair value (cost: 2026—$254,538; 2025—$246,579)
Fair value
Fair value
Subsidiaries [Member]
Class of Financing Receivable [Axis]
Class of Financing Receivable [Domain]
Entity Common Stock, Shares Outstanding
Earnings Per Share [Text Block]
Off-balance sheet risks liability amount
Hedging Designation [Axis]
Net unrealized holding (loss) gains arising during the period, tax
Financing Receivable, Credit Quality Indicator [Table]
Non-accrual loans
Financing Receivable, Nonaccrual
Net unrealized holding (loss) gain arising during the period, net of tax benefit (expense) of $34, ($323), $320, and ($982), respectively
Internal Credit Assessment [Axis]
Other Debt Obligations [Member]
Not Designated as Hedging Instrument [Member]
us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss
Net interest income after provision (credit) for credit losses
Weighted average shares outstanding:
Investments Classified by Contractual Maturity Date [Table Text Block]
Internal Credit Assessment [Domain]
Common stock, par value (in dollars per share)
Other liabilities
Derivative Contract [Domain]
Receivable [Domain]
Regulatory Capital Requirements under Banking Regulations [Text Block]
us-gaap_CashCashEquivalentsAndFederalFundsSold
Cash and cash equivalents
Total Assets
Total assets
Financing Receivable, Nonaccrual [Table]
us-gaap_CashAndCashEquivalentsAtCarryingValue
Cash and cash equivalents
Repurchase Agreements [Member]
Mortgage-related securities
Loans receivable
Financing Receivable, before Allowance for Credit Loss
Diluted earnings per share (in dollars per share)
Debt Securities, Trading, and Equity Securities, FV-NI [Table]
Real estate owned, net
Time Deposit Maturities [Table Text Block]
Gross charge-offs, two years before
Gross charge-offs, three years before
Gross charge-offs, current year
Gross charge-offs, one year before
Asset Class [Domain]
Accounts and Financing Receivables [Table]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Gross charge-offs, revolving
Gross charge-offs, four years before
Watch [Member]
Represents watch category.
Gross charge-offs, five years before
Receivable Type [Axis]
Total non-accrual loans to total loans receivable
The percentage of nonaccrual loans to total loans receivable.
Interest payments
Interest Rate Swap [Member]
Cash surrender value of life insurance
Interest Rate Lock Commitments [Member]
Community Banking [Member]
Represents community banking.
Total non-accrual loans to total assets
The percentage of nonaccrual loans to total assets.
wsbf_MortgageServicingRights
Total
Value of mortgage servicing rights.
wsbf_RealEstateOwnedFairValueDisclosure
Real estate owned
Represents fair value disclosure of real estate owned.
wsbf_UnpaidPrincipalBalanceOfLoansServicedForOthers
Unpaid Principal Balance of Loans Serviced for Others
The unpaid principal balance of loans serviced for others.
Future Amortization Expenses for Mortgage Servicing Rights [Table Text Block]
Tabular disclosure of future amortization expenses for mortgage servicing rights.
2026
wsbf_MortgageServicingRightsFutureAmortizationExpensesYearOne
Amount of amortization for mortgage servicing rights expected to be recognized during next fiscal year following current fiscal year.
2027
wsbf_MortgageServicingRightsFutureAmortizationExpensesYearTwo
Amount of amortization for mortgage servicing rights expected to be recognized during second fiscal year following current fiscal year.
2028
wsbf_MortgageServicingRightsFutureAmortizationExpensesYearThree
Amount of amortization for mortgage servicing rights expected to be recognized during third fiscal year following current fiscal year.
wsbf_MortgageServicingRightsNet
Mortgage servicing rights at beginning of the period
Mortgage servicing rights at end of the period, net
Value of mortage servicing rights after allowance.
us-gaap_StockholdersEquity
Total shareholders’ equity
Balances
Balances
2029
wsbf_MortgageServicingRightsFutureAmortizationExpensesYearFour
Amount of amortization for mortgage servicing rights expected to be recognized during fourth fiscal year following current fiscal year.
2030
wsbf_MortgageServicingRightsFutureAmortizationExpensesYearFive
Amount of amortization for mortgage servicing rights expected to be recognized during fifth fiscal year following current fiscal year.
Thereafter
wsbf_MortgageServicingRightsFutureAmortizationExpensesThereafter
Amount of amortization for mortgage servicing rights expected to be recognized during after fifth fiscal year following current fiscal year.
us-gaap_PaymentsOfDividendsCommonStock
Cash dividends on common stock
Interest Rate Swaption [Member]
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset
Commitments and contingencies (Note 8)