Securities- Unrealized Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 392,251	$ 1,456,921
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	6,796	77,421
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,603,962	1,550,911
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	273,306	248,005
Total investments with an unrealized loss, fair value	2,996,213	3,007,832
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	280,102	325,426
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	20,090	192,188
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	430	1,963
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	180,809	1,997
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	4,004	4
Total investments with an unrealized loss, fair value	200,899	194,185
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	4,434	1,967
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,888	46,062
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	62	2,224
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	400,168	350,094
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	31,079	34,094
Total investments with an unrealized loss, fair value	426,056	396,156
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	31,141	36,318
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	60,063	390,014
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,105	34,106
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	906,333	570,601
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	124,409	109,477
Total investments with an unrealized loss, fair value	966,396	960,615
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	125,514	143,583
State and municipal securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	170,787	568,691
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	74	18,863
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	635,725	304,451
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	59,267	59,694
Total investments with an unrealized loss, fair value	806,512	873,142
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	59,341	78,557
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,584	513
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	312	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	126,314	116,442
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	14,016	16,978
Total investments with an unrealized loss, fair value	151,898	116,955
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	14,328	16,983
Corporate notes
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	89,839	259,453
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,813	20,260
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	354,613	207,326
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	40,531	27,758
Total investments with an unrealized loss, fair value	444,452	466,779
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 45,344	$ 48,018