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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 | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023 | Jun. 30, 2023 | Mar. 31, 2023
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Allowance for Credit Losses and Credit Quality of Loans [Abstract] |  |  |  |  |
Allowance for credit losses | $ 120,500 | $ 115,300 | $ 114,400 | $ 100,400 | $ 100,250
Unfunded Commitment [Member] |  |  |  |  |
Allowance for Credit Losses and Credit Quality of Loans [Abstract] |  |  |  |  |
Allowance for credit losses | $ 4,300 |  | $ 5,100 |  |

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