Securities - Schedule of Unrealized Loss and Fair Value on Investments (Details) $ in Thousands	Sep. 30, 2026 USD ($)	Dec. 31, 2025 USD ($) security
Fair Value
Less Than 12 Months	$ 3,853,887	$ 1,079,884
12 Months or Longer	591,505	961,014
Total	4,445,392	2,040,898
Unrealized Losses
Less Than 12 Months	(218,891)	(4,059)
12 Months or Longer	(130,871)	(146,326)
Total	(349,762)	$ (150,385)
Number of individual securities | security		383
U.S. Treasury securities and obligations of U.S. government agencies
Fair Value
Less Than 12 Months	46,460	$ 21,846
12 Months or Longer	8,732	13,932
Total	55,192	35,778
Unrealized Losses
Less Than 12 Months	(2,252)	(31)
12 Months or Longer	(450)	(420)
Total	(2,702)	(451)
Residential mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities
Fair Value
Less Than 12 Months	2,995,789	378,739
12 Months or Longer	398,717	730,551
Total	3,394,506	1,109,290
Unrealized Losses
Less Than 12 Months	(182,019)	(1,625)
12 Months or Longer	(115,809)	(133,763)
Total	(297,828)	(135,388)
Commercial mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities
Fair Value
Less Than 12 Months	150,581	90,765
12 Months or Longer	68,196	95,090
Total	218,777	185,855
Unrealized Losses
Less Than 12 Months	(4,669)	(61)
12 Months or Longer	(6,508)	(5,867)
Total	(11,177)	(5,928)
Private mortgage-backed securities and collateralized mortgage obligations
Fair Value
Less Than 12 Months	7,924	969
12 Months or Longer	63,609	76,829
Total	71,533	77,798
Unrealized Losses
Less Than 12 Months	(231)	(1)
12 Months or Longer	(6,359)	(5,009)
Total	(6,590)	(5,010)
CLOs
Fair Value
Less Than 12 Months	194,479	211,052
12 Months or Longer	46,960	38,882
Total	241,439	249,934
Unrealized Losses
Less Than 12 Months	(627)	(320)
12 Months or Longer	(231)	(192)
Total	(858)	(512)
Obligations of state and political subdivisions
Fair Value
Less Than 12 Months	304,841	244,168
12 Months or Longer	5,291	5,730
Total	310,132	249,898
Unrealized Losses
Less Than 12 Months	(22,133)	(1,445)
12 Months or Longer	(1,514)	(1,075)
Total	(23,647)	(2,520)
Other debt securities
Fair Value
Less Than 12 Months	153,813	132,345
12 Months or Longer	0	0
Total	153,813	132,345
Unrealized Losses
Less Than 12 Months	(6,960)	(576)
12 Months or Longer	0	0
Total	$ (6,960)	$ (576)