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Disclosures About Fair Value of Assets - Reconciliation of Beginning and Ending Balances of Recurring Fair Value Measurements Recognized in Accompanying Balance Sheet (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
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Sep. 30, 2025 | Jun. 30, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | $ 3,177 | $ 3,548
Transfers into Level 3 | 60 | 130
Transfers out of Level 3 | (44) | (122)
Total realized and unrealized gains and losses included in net income | (15) | (70)
Settlements | 0 | (309)
Ending Balance | 3,178 | 3,177
Total gains or losses for the period included in net income attributable to the change in unrealized gains or losses related to assets and liabilities still held at the reporting date | (15) | (70)
State and Political Subdivision [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 1,748 | 2,057
Settlements | 0 | (309)
Ending Balance | 1,748 | 1,748
Mortgage Servicing Rights [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 1,429 | 1,491
Transfers into Level 3 | 60 | 130
Transfers out of Level 3 | (44) | (122)
Total realized and unrealized gains and losses included in net income | (15) | (70)
Ending Balance | 1,430 | 1,429
Total gains or losses for the period included in net income attributable to the change in unrealized gains or losses related to assets and liabilities still held at the reporting date | $ (15) | $ (70)

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