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Loans and Leases and the Allowance for Credit Losses - Summary of Payment Status of Loans Modified (Detail) - USD ($) $ in Thousands | Sep. 30, 2024 | Sep. 30, 2023
--- | --- | ---
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | $ 1,247,000 | $ 1,198,000
Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 986,000 | 1,114,000
30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 211,000 | 56,000
Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 50,000 | 28,000
Commercial and industrial |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 317,000 | 127,000
Commercial and industrial | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 308,000 | 109,000
Commercial and industrial | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 5,000 | 4,000
Commercial and industrial | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 4,000 | 14,000
Commercial Real Estate | Commercial |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 515,000 | 423,000
Commercial Real Estate | Commercial | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 422,000 | 406,000
Commercial Real Estate | Commercial | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 84,000 | 17,000
Commercial Real Estate | Commercial | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 9,000 | 0
Commercial Real Estate | Residential builder and developer |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 14,000 | 71,000
Commercial Real Estate | Residential builder and developer | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 13,000 | 71,000
Commercial Real Estate | Residential builder and developer | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 1,000 | 0
Commercial Real Estate | Residential builder and developer | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Commercial Real Estate | Other commercial construction |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 215,000 | 440,000
Commercial Real Estate | Other commercial construction | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 141,000 | 440,000
Commercial Real Estate | Other commercial construction | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 74,000 | 0
Commercial Real Estate | Other commercial construction | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Residential Real Estate | Residential |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 175,000 | 125,000
Residential Real Estate | Residential | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 93,000 | 79,000
Residential Real Estate | Residential | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 45,000 | 34,000
Residential Real Estate | Residential | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 37,000 | 12,000
Residential Real Estate | Residential — limited documentation |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 8,000 | 11,000
Residential Real Estate | Residential — limited documentation | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 6,000 | 8,000
Residential Real Estate | Residential — limited documentation | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 2,000 | 1,000
Residential Real Estate | Residential — limited documentation | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 2,000
Consumer: | Home equity lines and loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 2,000 | 1,000
Consumer: | Home equity lines and loans | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 2,000 | 1,000
Consumer: | Home equity lines and loans | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Home equity lines and loans | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Recreational finance |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 1,000 | 0
Consumer: | Recreational finance | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 1,000 | 0
Consumer: | Recreational finance | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Recreational finance | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Automobile |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Automobile | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Automobile | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Automobile | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Other |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Other | Current |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Other | 30-89 Days Past Due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | 0 | 0
Consumer: | Other | Accruing Loans Past Due 90 Days or More |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Amortized cost | $ 0 | $ 0

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