Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 208,781	$ 127,160
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,458	714
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,303,045	1,326,392
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	171,795	151,750
Debt Securities, Available-for-sale, Unrealized Loss Position	1,511,826	1,453,552
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	173,253	152,464
Obligations of U.S. Government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	20,179	25,886
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	85	85
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	259,528	247,027
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	19,590	20,283
Debt Securities, Available-for-sale, Unrealized Loss Position	279,707	272,913
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	19,675	20,368
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,905	1,168
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	32	163
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	405,833	428,171
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	86,070	68,604
Debt Securities, Available-for-sale, Unrealized Loss Position	407,738	429,339
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	86,102	68,767
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	124,783	58,249
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,207	417
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	533,940	540,032
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	62,406	58,666
Debt Securities, Available-for-sale, Unrealized Loss Position	658,723	598,281
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	63,613	59,083
U.S. Treasury bills
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,830	7,574
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	920	1,176
Debt Securities, Available-for-sale, Unrealized Loss Position	7,830	7,574
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	920	1,176
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	61,914	41,857
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	134	49
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	95,914	103,588
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,809	3,021
Debt Securities, Available-for-sale, Unrealized Loss Position	157,828	145,445
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 2,943	$ 3,070