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Loans and Allowance for Credit Losses - Additional Information (Detail) - USD ($) | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Non Accrual Status Of Loans After Number Of Days Past Due |  |  | 90 days |  |
Default Status Of TDRs After Number Of Days Past Due |  |  | 90 days |  |
Charge-offs | $ 9,789,000 | $ 4,598,000 | $ 20,821,000 | $ 15,824,000 | $ 33,267,000
Unfunded commitments related to nonperforming loans | 200,000 |  | 200,000 |  | 100,000
Off balance sheet reserve to nonperforming loans | 0 |  | 0 |  | 0
Total gains or losses included in earnings | 4,000 | 0 | (7,000) | 0 |
Recorded investment | 74,723,000 |  | 74,723,000 |  | 39,472,000
Loans and Leases Receivable, Gross | 8,965,500,000 |  | 8,965,500,000 |  | 8,968,761,000
Loans and Leases Receivable, Net of Deferred Income | 8,965,500,000 |  | $ 8,965,500,000 |  | 8,968,761,000
Forecasted Value, National Unemployment, Percent |  |  | 4.26% |  |
Financing Receivable, before Allowance for Credit Loss | 8,965,500,000 |  | $ 8,965,500,000 |  | 8,968,761,000
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  |  | 17,500,000 | 13,800,000 |
Post- Modification Outstanding Recorded Investment | 5,990,000 | 207,000 | 17,622,000 | 632,000 |
Net Deferred Fees |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Loans and Leases Receivable, Deferred Income | 13,600,000 |  | 13,600,000 |  | 8,200,000
Unearned Premiums and Discounts |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Loans and Leases Receivable, Deferred Income | (20,100,000) |  | (20,100,000) |  | (25,700,000)
Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 27,585,000 |  | 27,585,000 |  | 16,958,000
Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 8,854,453,000 |  | $ 8,854,453,000 |  | 8,899,737,000
Weighted average [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Forecasted Value, National Unemployment, Percent |  |  | 4.87% |  |
Maximum [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Forecasted Value, National Unemployment, Percent |  |  | 5.07% |  |
Time and Demand Loans |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | $ 8,161,000 |  | 16,147,000
Loans and Leases Receivable, Gross | 1,141,477,000 |  | 1,141,477,000 |  | 1,187,300,000
Multifamily |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | 0 |  | 0
Loans and Leases Receivable, Gross | 540,427,000 |  | 540,427,000 |  | 551,142,000
Nonowner Occupied Commercial Real Estate |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | 507,000 |  | 4,705,000
Loans and Leases Receivable, Gross | 1,803,084,000 |  | 1,803,084,000 |  | 1,772,785,000
Commercial, financial, agricultural and other [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 5,980,000 | 1,762,000 | 11,230,000 | 9,102,000 |
Loans and Leases Receivable, Gross | 1,629,535,000 |  | 1,629,535,000 |  | 1,543,349,000
Loans and Leases Receivable, Net of Deferred Income | 1,629,535,000 |  | 1,629,535,000 |  | 1,543,349,000
Financing Receivable, before Allowance for Credit Loss | 1,629,535,000 |  | 1,629,535,000 |  | 1,543,349,000
Post- Modification Outstanding Recorded Investment | 5,794,000 |  | 7,247,000 |  |
Commercial, financial, agricultural and other [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 1,809,000 |  | 1,809,000 |  | 1,206,000
Commercial, financial, agricultural and other [Member] | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 1,609,002,000 |  | 1,609,002,000 |  | 1,527,151,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 4,784,000 | 954,000 | 8,161,000 | 7,424,000 |
Loans and Leases Receivable, Gross | 1,141,477,000 |  | 1,141,477,000 |  | 1,187,300,000
Loans and Leases Receivable, Net of Deferred Income | 1,141,477,000 |  | 1,141,477,000 |  | 1,187,300,000
Financing Receivable, before Allowance for Credit Loss | 1,141,477,000 |  | 1,141,477,000 |  | 1,187,300,000
Post- Modification Outstanding Recorded Investment | 5,794,000 |  | 7,083,000 |  |
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 891,000 |  | 891,000 |  | 565,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 1,123,751,000 |  | 1,123,751,000 |  | 1,172,639,000
Commercial Real Estate [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 1,423,000 | 172,000 | 2,047,000 | 1,689,000 |
Loans and Leases Receivable, Gross | 3,069,438,000 |  | 3,069,438,000 |  | 3,053,152,000
Loans and Leases Receivable, Net of Deferred Income | 3,069,438,000 |  | 3,069,438,000 |  | 3,053,152,000
Financing Receivable, before Allowance for Credit Loss | 3,069,438,000 |  | 3,069,438,000 |  | 3,053,152,000
Post- Modification Outstanding Recorded Investment |  |  | 9,674,000 |  |
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 10,599,000 |  | 10,599,000 |  | 4,157,000
Commercial Real Estate [Member] | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 3,015,188,000 |  | 3,015,188,000 |  | 3,028,101,000
Commercial Real Estate [Member] | Multifamily |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 0 | 0 | 0 | 0 |
Loans and Leases Receivable, Gross | 540,427,000 |  | 540,427,000 |  | 551,142,000
Loans and Leases Receivable, Net of Deferred Income | 540,427,000 |  | 540,427,000 |  | 551,142,000
Financing Receivable, before Allowance for Credit Loss | 540,427,000 |  | 540,427,000 |  | 551,142,000
Commercial Real Estate [Member] | Multifamily | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 69,000 |  | 69,000 |  | 0
Commercial Real Estate [Member] | Multifamily | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 540,337,000 |  | 540,337,000 |  | 551,087,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 37,000 | $ 172,000 | 507,000 | 172,000 |
Loans and Leases Receivable, Gross | 1,803,084,000 |  | 1,803,084,000 |  | 1,772,785,000
Loans and Leases Receivable, Net of Deferred Income | 1,803,084,000 |  | 1,803,084,000 |  | 1,772,785,000
Financing Receivable, before Allowance for Credit Loss | 1,803,084,000 |  | 1,803,084,000 |  | 1,772,785,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 6,520,000 |  | 6,520,000 |  | 2,303,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 1,761,070,000 |  | $ 1,761,070,000 |  | 1,752,691,000
Loans to individuals [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Non Accrual Status Of Loans After Number Of Days Past Due |  |  | 150 days |  |
Nonaccrual Commercial Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Loans Held for sale, Amount | $ 0 |  | $ 0 |  | $ 0
Loans and Leases Receivable, Gain (Loss) on Sales, Net |  |  | $ 0 | $ 0 |

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