Note 4 - Mortgage Servicing Rights - Future Amortization Expenses (Details) $ in Thousands	Mar. 31, 2024 USD ($)
2024	$ 277
2025	393
2026	354
2027	314
2028	275
Thereafter	548
Total	$ 2,161

Value of mortgage servicing rights.

No definition available.

Name:	wsbf_MortgageServicingRights
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during after fifth fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesThereafter
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during fifth fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesYearFive
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during fourth fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesYearFour
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during next fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesYearOne
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during third fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesYearThree
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of amortization for mortgage servicing rights expected to be recognized during second fiscal year following current fiscal year.

No definition available.

Name:	wsbf_MortgageServicingRightsFutureAmortizationExpensesYearTwo
Namespace Prefix:	wsbf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant