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Fair Value of Financial Instruments - Narrative (Details) - USD ($) | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Dec. 31, 2023 | Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Servicing asset at fair value, gain (loss) on disposal | $ 410,000 |  |  |
Mortgage servicing rights assets recognized or recorded during period | 0 | $ 149,000 |  |
Carrying value MSR assets | 0 | $ 18,261,000 | $ 15,637,000 | $ 20,824,000
Non-marketable equity securities held in other financial institutions | 53,870,000 |  | 55,190,000 |
Impairment recorded on investments in equity securities that do not have readily determinable fair values | 0 |  |  |
Loan balance individually evaluated | 14,731,000 |  | 5,011,000 |
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Loan balance individually evaluated | 3,900,000 |  | 3,800,000 |
Foreclosed assets | 3,900,000 |  | 3,900,000 |
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring | Real estate | Residential real estate |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Residential mortgage loans in the process of foreclosure | $ 944,000 |  | $ 0 |
Minimum | Measurement Input, Credit Spread |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Credit spread, securities at fair value through income | 0.83% |  | 0.83% |
Maximum | Measurement Input, Credit Spread |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |
Credit spread, securities at fair value through income | 2.27% |  | 2.27% |

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