Investment Securities - Held-to-Maturity with Unrecognized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value
Less than 12 months	$ 0	$ 1,560,831
12 months or longer	2,530,274	1,052,753
Total	2,530,274	2,613,584
Unrecognized Losses
Less than 12 months	0	(280,316)
12 months or longer	(414,105)	(165,370)
Total	(414,105)	(445,686)
U.S. government-sponsored entities and agencies
Fair Value
Less than 12 months	0	354,293
12 months or longer	671,126	302,066
Total	671,126	656,359
Unrecognized Losses
Less than 12 months	0	(110,523)
12 months or longer	(154,827)	(52,287)
Total	(154,827)	(162,810)
Mortgage-backed securities
Fair Value
Less than 12 months	0	367,849
12 months or longer	881,994	615,114
Total	881,994	982,963
Unrecognized Losses
Less than 12 months	0	(42,438)
12 months or longer	(147,137)	(81,416)
Total	(147,137)	(123,854)
States and political subdivisions
Fair Value
Less than 12 months	0	838,689
12 months or longer	977,154	135,573
Total	977,154	974,262
Unrecognized Losses
Less than 12 months	0	(127,355)
12 months or longer	(112,141)	(31,667)
Total	$ (112,141)	$ (159,022)