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Loans and Allowance for Credit Losses - Additional Information (Detail) |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2025 USD ($) Loans | Sep. 30, 2025 USD ($) SecurityLoan | Jun. 30, 2025 USD ($) SecurityLoan
Loans and Allowance for Credit Losses [Line Items] |  |  |
Loans held for sale |  |  | $ 0
Maximum term of fixed-rate one- to four-family residential mortgage loans |  | 15 years |
Number of default loans | SecurityLoan |  | 0 | 0
Foreclosed residential real estate properties | $ 40,000 | $ 40,000 | $ 165,000
Financing Receivable, Accrued Interest, after Allowance for Credit Loss | 3,200,000 | 3,200,000 |
Financing Receivable, Allowance for Credit Loss, Individually Evaluated | 122,000 | 122,000 |
Fair Value, Concentration of Risk, Maximum Amount of Loss [Member] |  |  |
Loans and Allowance for Credit Losses [Line Items] |  |  |
Commercial and multi-family real estate | 326,254,000 | $ 326,254,000 | 339,861,000
Troubled Debt Restructurings [Member] |  |  |
Loans and Allowance for Credit Losses [Line Items] |  |  |
Minimum period for default |  | 90 days |
Residential Real Estate [Member] |  |  |
Loans and Allowance for Credit Losses [Line Items] |  |  |
Foreclosed residential real estate properties | 40,000,000 | $ 40,000,000 | 165,000,000
One- to four-family [Member] |  |  |
Loans and Allowance for Credit Losses [Line Items] |  |  |
Loans held for sale | $ 353,500,000 | $ 353,500,000 |
Maximum term of fixed-rate one- to four-family residential mortgage loans |  | 15 years |
Mortgage Loans On Real Estate Number Of Loans | Loans | 3 |  |
Purchased Loans and Loan Participations [Member] |  |  |
Loans and Allowance for Credit Losses [Line Items] |  |  |
Approximate amount of purchase loans included in loans receivable | $ 226,000 | $ 226,000 | 198,000
Approximate amount of loans included on out-of-area participation | 47,888,000 | 47,888,000 | 55,849,000
Amount within 100 miles of primary area | $ 44,681,000 | $ 44,681,000 | $ 38,860,000

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