Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023
Financing Receivable, Past Due [Line Items]
FinancingReceivableNonaccrualWithAllowance	$ 33
Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	15,790
Financing Receivable, Nonaccrual	15,823	$ 12,261
One-to-four family | Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	3,919
FinancingReceivableNonaccrualWithAllowance	23
Financing Receivable, Nonaccrual	3,942	4,001
Multifamily | Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	1,131
Financing Receivable, Nonaccrual	1,131	71
Commercial real estate | Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	4,522
Financing Receivable, Nonaccrual	4,522	7,190
Business | Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	6,188
FinancingReceivableNonaccrualWithAllowance	10
Financing Receivable, Nonaccrual	6,198	998
Consumer | Nonperforming
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, No Allowance	30
Financing Receivable, Nonaccrual	$ 30	$ 1