Investments - Maturity Table (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,428,037	$ 2,563,984
Estimated Fair Value	2,283,262	$ 2,411,622
2024
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	349,887
Estimated Fair Value	346,293
2025
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	299,312
Estimated Fair Value	292,886
2026
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	548,929
Estimated Fair Value	507,701
2027
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	98,814
Estimated Fair Value	94,851
2038
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	67
Estimated Fair Value	67
2039
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	570
Estimated Fair Value	552
2042
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,201
Estimated Fair Value	1,870
2043
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,864
Estimated Fair Value	3,396
2044
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,297
Estimated Fair Value	3,846
2045
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,615
Estimated Fair Value	4,011
2046
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,389
Estimated Fair Value	6,370
2047
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,359
Estimated Fair Value	6,424
2048
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,731
Estimated Fair Value	1,650
2049
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,114
Estimated Fair Value	13,095
2050
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	103,837
Estimated Fair Value	80,824
2051
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	149,872
Estimated Fair Value	115,523
2052
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	60,026
Estimated Fair Value	52,066
2053
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	323,017
Estimated Fair Value	315,286
2054
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	120,309
Estimated Fair Value	112,740
2055
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	78,597
Estimated Fair Value	75,905
2056
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	205,354
Estimated Fair Value	204,708
2058
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	42,876
Estimated Fair Value	$ 43,198