Investments - Maturity Table (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,956,353	$ 1,812,408
Estimated Fair Value	2,847,109	$ 1,758,070
2026
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	198,057
Estimated Fair Value	197,969
2027
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	706,029
Estimated Fair Value	703,506
2028
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	409,804
Estimated Fair Value	405,124
2029
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	108,844
Estimated Fair Value	107,199
2030
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	107,845
Estimated Fair Value	105,602
2031
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	108,450
Estimated Fair Value	105,661
2038
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	60
Estimated Fair Value	58
2039
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	386
Estimated Fair Value	361
2042
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,545
Estimated Fair Value	1,288
2043
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,989
Estimated Fair Value	2,526
2044
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,319
Estimated Fair Value	2,824
2045
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,046
Estimated Fair Value	3,389
2046
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	6,153
Estimated Fair Value	5,079
2047
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,646
Estimated Fair Value	4,730
2048
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,614
Estimated Fair Value	1,420
2049
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,881
Estimated Fair Value	9,885
2050
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	89,388
Estimated Fair Value	67,071
2051
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	125,718
Estimated Fair Value	92,965
2052
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	46,257
Estimated Fair Value	38,541
2053
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	242,570
Estimated Fair Value	236,843
2054
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	216,775
Estimated Fair Value	208,104
2055
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	215,407
Estimated Fair Value	209,034
2056
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	316,058
Estimated Fair Value	309,979
2058
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,512
Estimated Fair Value	$ 27,951