Securities - Schedule of Unrealized Loss and Fair Value on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value
Less Than 12 Months	$ 291,773	$ 1,058,560
12 Months or Longer	1,521,622	753,962
Total	1,813,395	1,812,522
Unrealized Losses
Less Than 12 Months	(19,787)	(73,965)
12 Months or Longer	(267,557)	(174,697)
Total	(287,344)	(248,662)
U.S. Treasury securities and obligations of U.S. government agencies
Fair Value
Less Than 12 Months	33,881	3,788
12 Months or Longer	3,569	249
Total	37,450	4,037
Unrealized Losses
Less Than 12 Months	(467)	(328)
12 Months or Longer	(487)	(11)
Total	(954)	(339)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities
Fair Value
Less Than 12 Months	174,339	646,651
12 Months or Longer	1,142,859	667,520
Total	1,317,198	1,314,171
Unrealized Losses
Less Than 12 Months	(18,084)	(54,956)
12 Months or Longer	(248,641)	(168,127)
Total	(266,725)	(223,083)
Private mortgage-backed securities and collateralized mortgage obligations
Fair Value
Less Than 12 Months	4,814	130,488
12 Months or Longer	119,348	25,234
Total	124,162	155,722
Unrealized Losses
Less Than 12 Months	(84)	(8,255)
12 Months or Longer	(13,843)	(4,576)
Total	(13,927)	(12,831)
Collateralized loan obligations
Fair Value
Less Than 12 Months	59,580	242,370
12 Months or Longer	244,588	60,534
Total	304,168	302,904
Unrealized Losses
Less Than 12 Months	(730)	(8,343)
12 Months or Longer	(2,766)	(1,908)
Total	(3,496)	(10,251)
Obligations of state and political subdivisions
Fair Value
Less Than 12 Months	8,394	23,804
12 Months or Longer	11,258	425
Total	19,652	24,229
Unrealized Losses
Less Than 12 Months	(296)	(1,656)
12 Months or Longer	(1,820)	(75)
Total	(2,116)	(1,731)
Other debt securities
Fair Value
Less Than 12 Months	10,765	11,459
12 Months or Longer	0	0
Total	10,765	11,459
Unrealized Losses
Less Than 12 Months	(126)	(427)
12 Months or Longer	0	0
Total	$ (126)	$ (427)