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Securities - Narrative (Details) | Mar. 31, 2024 USD ($) investment | Dec. 31, 2023 USD ($) investment | Dec. 31, 2009 USD ($)
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Debt Securities, Available-for-sale [Line Items] |  |  |
Carrying value of securities pledged to secure repurchase agreements, public and trust deposits and other by law | $ 380,442,000 | $ 366,576,000 |
Allowance for credit losses for available-for-sale debt securities | 0 | 0 |
Accrued interest receivable on available-for-sale debt securities | 8,608,000 | 9,620,000 |
Original amount in non-controlling investment security in a single banking organization | 353,000 | $ 353,000 | $ 1,350,000
Additional impairment on equity securities recognized through earnings | $ 0 |  | $ 997,000
Equity Securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Number of non-controlling investments in a single banking organization | investment | 1 | 1 |

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