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Investments - Maturity Table (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 2,423,183 | $ 2,563,984
Estimated Fair Value | 2,271,108 | $ 2,411,622
2024 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 449,757 |
Estimated Fair Value | 442,325 |
2025 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 299,063 |
Estimated Fair Value | 290,830 |
2026 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 548,807 |
Estimated Fair Value | 504,757 |
2027 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 98,713 |
Estimated Fair Value | 94,816 |
2038 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 68 |
Estimated Fair Value | 68 |
2039 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 581 |
Estimated Fair Value | 566 |
2042 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,252 |
Estimated Fair Value | 1,928 |
2043 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 4,079 |
Estimated Fair Value | 3,626 |
2044 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 4,467 |
Estimated Fair Value | 4,047 |
2045 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 4,898 |
Estimated Fair Value | 4,300 |
2046 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 7,451 |
Estimated Fair Value | 6,498 |
2047 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 7,409 |
Estimated Fair Value | 6,533 |
2048 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,008 |
Estimated Fair Value | 1,923 |
2049 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 15,238 |
Estimated Fair Value | 13,344 |
2050 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 106,282 |
Estimated Fair Value | 83,558 |
2051 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 153,057 |
Estimated Fair Value | 119,243 |
2052 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 51,825 |
Estimated Fair Value | 44,160 |
2053 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 242,958 |
Estimated Fair Value | 235,101 |
2054 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 86,866 |
Estimated Fair Value | 79,516 |
2055 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 82,255 |
Estimated Fair Value | 79,089 |
2056 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 210,422 |
Estimated Fair Value | 209,947 |
2058 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 44,727 |
Estimated Fair Value | $ 44,933 |

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