Securities - Schedule of Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
AFS debt securities:
Amortized Cost	$ 11,505,775	$ 6,916,491
Gross Unrealized Gains	15,273	783
Gross Unrealized Losses	(674,237)	(728,937)
Fair Value	10,846,811	6,188,337
HTM debt securities
Amortized Cost	2,917,413	2,956,040
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(529,659)	(502,069)
Fair Value	2,387,754	2,453,971
Total debt securities
Amortized Cost	14,423,188	9,872,531
Gross Unrealized Gains	15,273	783
Gross Unrealized Losses	(1,203,896)	(1,231,006)
Fair Value	13,234,565	8,642,308
AFS and HTM, accrued interest	45,000	44,000
Government National Mortgage Association (GNMA)
AFS debt securities:
Amortized Cost	7,300,000	1,300,000
Fair Value	7,200,000	1,200,000
HTM debt securities
Amortized Cost	86,000	92,000
Fair Value	68,000	75,000
U.S. Treasury securities
AFS debt securities:
Amortized Cost	676,300	1,112,587
Gross Unrealized Gains	0	101
Gross Unrealized Losses	(38,035)	(52,313)
Fair Value	638,265	1,060,375
HTM debt securities
Amortized Cost	535,080	529,548
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(35,222)	(40,997)
Fair Value	499,858	488,551
U.S. government agency and U.S. government-sponsored enterprise debt securities
AFS debt securities:
Amortized Cost	308,220	412,086
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(45,633)	(47,640)
Fair Value	262,587	364,446
HTM debt securities
Amortized Cost	1,004,479	1,001,836
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(200,259)	(186,904)
Fair Value	804,220	814,932
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
AFS debt securities:
Amortized Cost	472,535	531,377
Gross Unrealized Gains	886	158
Gross Unrealized Losses	(47,207)	(63,276)
Fair Value	426,214	468,259
HTM debt securities
Amortized Cost	486,388	493,348
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(91,461)	(88,968)
Fair Value	394,927	404,380
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
AFS debt securities:
Amortized Cost	7,974,768	1,956,927
Gross Unrealized Gains	12,278	380
Gross Unrealized Losses	(248,786)	(229,713)
Fair Value	7,738,260	1,727,594
HTM debt securities
Amortized Cost	703,833	742,436
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(155,626)	(142,119)
Fair Value	548,207	600,317
Municipal securities
AFS debt securities:
Amortized Cost	287,301	297,283
Gross Unrealized Gains	38	75
Gross Unrealized Losses	(37,186)	(36,342)
Fair Value	250,153	261,016
HTM debt securities
Amortized Cost	187,633	188,872
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(47,091)	(43,081)
Fair Value	140,542	145,791
Non-agency commercial mortgage-backed Securities
AFS debt securities:
Amortized Cost	294,235	409,578
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(35,767)	(42,062)
Fair Value	258,470	367,516
Non-agency residential mortgage-backed Securities
AFS debt securities:
Amortized Cost	514,527	643,335
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(80,919)	(89,664)
Fair Value	433,608	553,671
Corporate debt securities
AFS debt securities:
Amortized Cost	653,500	653,501
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(127,334)	(151,076)
Fair Value	526,166	502,425
Foreign government bonds
AFS debt securities:
Amortized Cost	244,803	239,333
Gross Unrealized Gains	2,069	69
Gross Unrealized Losses	(12,992)	(11,528)
Fair Value	233,880	227,874
Asset-backed securities
AFS debt securities:
Amortized Cost	35,086	43,234
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(371)	(934)
Fair Value	34,715	42,300
Collateralized loan obligations (“CLOs”)
AFS debt securities:
Amortized Cost	44,500	617,250
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7)	(4,389)
Fair Value	$ 44,493	$ 612,861