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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, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
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 | $ 13,577,000 | $ 9,789,000 | $ 26,013,000 | $ 20,821,000 | $ 35,428,000
Unfunded commitments related to nonperforming loans | 7,500,000 |  | 7,500,000 |  | 300,000
Off balance sheet reserve to nonperforming loans | 0 |  | 0 |  | 0
Total gains or losses included in earnings |  |  | $ 0 | 0 |
Forecasted Value, National Unemployment, Percent |  |  | 4.32% |  |
Financing Receivable, before Allowance for Credit Loss | 9,688,288,000 |  | $ 9,688,288,000 |  | 8,983,754,000
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery |  |  | 18,100,000 | 17,500,000 |
Post- Modification Outstanding Recorded Investment | 6,552,000 | 5,990,000 | 26,816,000 | 17,622,000 |
Small Business Administration Guarantee |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 24,400,000 |  | 24,400,000 |  | 8,100,000
Net Deferred Fees |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Unearned Deferred (Fees) Costs on Loans | 19,000,000 |  | 19,000,000 |  | 14,700,000
Unearned Premiums and Discounts |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Unearned Deferred (Fees) Costs on Loans | (24,400,000) |  | (24,400,000) |  | (18,900,000)
Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 32,069,000 |  | 32,069,000 |  | 14,673,000
Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 9,559,832,000 |  | 9,559,832,000 |  | 8,900,116,000
Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 87,547,000 |  | $ 87,547,000 |  | 61,456,000
Weighted average [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Forecasted Value, National Unemployment, Percent |  |  | 5.15% |  |
Maximum [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Forecasted Value, National Unemployment, Percent |  |  | 5.54% |  |
Time and Demand Loans |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | $ 9,871,000 |  | 11,131,000
Financing Receivable, before Allowance for Credit Loss | 1,251,980,000 |  | 1,251,980,000 |  | 1,133,595,000
Multifamily |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | 461,000 |  | 0
Financing Receivable, before Allowance for Credit Loss | 656,182,000 |  | 656,182,000 |  | 597,145,000
Nonowner Occupied Commercial Real Estate |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs |  |  | 3,463,000 |  | 7,138,000
Financing Receivable, before Allowance for Credit Loss | 1,944,990,000 |  | 1,944,990,000 |  | 1,804,950,000
Commercial, financial, agricultural and other [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 7,418,000 | 5,980,000 | 12,840,000 | 11,230,000 |
Financing Receivable, before Allowance for Credit Loss | 2,009,025,000 |  | 2,009,025,000 |  | 1,677,989,000
Post- Modification Outstanding Recorded Investment |  | 5,794,000 | 16,324,000 | 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 | 8,589,000 |  | 8,589,000 |  | 2,379,000
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 | 1,952,203,000 |  | 1,952,203,000 |  | 1,659,053,000
Commercial, financial, agricultural and other [Member] | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 44,738,000 |  | 44,738,000 |  | 14,987,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 6,532,000 | 4,784,000 | 9,871,000 | 8,161,000 |
Financing Receivable, before Allowance for Credit Loss | 1,251,980,000 |  | 1,251,980,000 |  | 1,133,595,000
Post- Modification Outstanding Recorded Investment |  | 5,794,000 | 16,015,000 |  |
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 | 7,197,000 |  | 7,197,000 |  | 649,000
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 | 1,198,295,000 |  | 1,198,295,000 |  | 1,117,613,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 43,890,000 |  | 43,890,000 |  | 14,181,000
Commercial Real Estate [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 3,049,000 | 1,423,000 | 5,137,000 | 2,047,000 |
Financing Receivable, before Allowance for Credit Loss | 3,408,801,000 |  | 3,408,801,000 |  | 3,124,704,000
Post- Modification Outstanding Recorded Investment | 6,207,000 |  | 9,408,000 | 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 | 5,783,000 |  | 5,783,000 |  | 1,597,000
Commercial Real Estate [Member] | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 3,373,120,000 |  | 3,373,120,000 |  | 3,089,905,000
Commercial Real Estate [Member] | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 28,924,000 |  | 28,924,000 |  | 32,103,000
Commercial Real Estate [Member] | Multifamily |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 461,000 | 0 | 461,000 | 0 |
Financing Receivable, before Allowance for Credit Loss | 656,182,000 |  | 656,182,000 |  | 597,145,000
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 | 0 |  | 0 |  | 212,000
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 | 656,163,000 |  | 656,163,000 |  | 596,913,000
Commercial Real Estate [Member] | Multifamily | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 19,000 |  | 19,000 |  | 20,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 2,588,000 | 37,000 | 3,463,000 | 507,000 |
Financing Receivable, before Allowance for Credit Loss | 1,944,990,000 |  | 1,944,990,000 |  | 1,804,950,000
Post- Modification Outstanding Recorded Investment | 6,207,000 |  | 9,408,000 |  |
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 | 3,063,000 |  | 3,063,000 |  | 72,000
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 | 1,928,937,000 |  | 1,928,937,000 |  | 1,779,586,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 12,664,000 |  | 12,664,000 |  | 24,550,000
Loans to individuals [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Charge-offs | 2,156,000 | $ 2,280,000 | 6,856,000 | 7,148,000 |
Financing Receivable, before Allowance for Credit Loss | 1,442,295,000 |  | 1,442,295,000 |  | 1,355,974,000
Post- Modification Outstanding Recorded Investment |  |  |  | 32,000 |
Loans to individuals [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 | 4,787,000 |  | 4,787,000 |  | 5,020,000
Loans to individuals [Member] | Financial Asset, Not Past Due |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 1,436,405,000 |  | 1,436,405,000 |  | 1,349,111,000
Loans to individuals [Member] | Non Accrual Loans [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss | 19,000 |  | $ 19,000 |  | 250,000
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 | $ 1,100,000 |  | $ 1,100,000 |  | $ 0
Loans and Leases Receivable, Gain (Loss) on Sales, Net |  |  | $ 0 | $ 0 |

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