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Allowance for Credit Losses and Credit Quality of Loans, Allowance for Credit Losses on Off-Balance Sheet Credit Exposures (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |  |  |  |
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Jun. 30, 2025 | Dec. 31, 2024 | Jun. 30, 2024 | Dec. 31, 2023
Allowance for Credit Losses and Credit Quality of Loans [Abstract] |  |  |  |  |  |  |  |
Allowance for credit losses | $ 139,000 | $ 119,500 | $ 139,000 | $ 119,500 | $ 140,200 | $ 116,000 | $ 120,500 | $ 114,400
Unfunded Loan Commitments [Member] |  |  |  |  |  |  |  |
Allowance for Credit Losses and Credit Quality of Loans [Abstract] |  |  |  |  |  |  |  |
Allowance for credit losses | 5,900 |  | 5,900 |  |  | $ 4,400 |  |
Reserve for credit losses | $ (300) | $ 300 | 1,500 | $ (600) |  |  |  |
Acquired acquisition-related provision for credit losses |  |  | $ 500 |  |  |  |  |

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