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Securities - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2024
Schedule of Available-for-sale Securities [Line Items] |  |
Realized gains on sales | $ 22.0 |
Investments pledged, carrying value | 194.1 | $ 221.9
Investments pledged, carrying par value |  | 30.0
Federal Reserve's Bank Term Funding Program [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Investments pledged, carrying value | $ 61.7 | $ 29.9

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