Investment Securities - Securities Available for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 5,654,617	$ 10,603,518
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6	163,035
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(811,136)	(72,095)
Securities available-for-sale, at fair value	4,843,487	10,694,458
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,685,038	2,921,993
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	8,866
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(442,996)	(32,649)
Securities available-for-sale, at fair value	2,242,042	2,898,210
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	771,145	973,555
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	1,641
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(101,075)	(8,298)
Securities available-for-sale, at fair value	670,070	966,898
Government agency and government-sponsored enterprise pass through securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	549,492	1,660,516
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	37,664
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(61,886)	(9,213)
Securities available-for-sale, at fair value	487,606	1,688,967
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	517,174	1,021,716
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	22,288
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(60,111)	(5,870)
Securities available-for-sale, at fair value	457,063	1,038,134
Municipal Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	399,724	2,248,749
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	75,192
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(60,398)	(7,973)
Securities available-for-sale, at fair value	339,326	2,315,968
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	344,767	514,077
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6	13,774
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(32,868)	(757)
Securities available-for-sale, at fair value	311,905	527,094
Interest Receivable	13,500
Private Label Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	207,123	265,851
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	1,857
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(40,399)	(3,291)
Securities available-for-sale, at fair value	166,724	264,417
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	109,159	385,410
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	396
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(6,898)	(444)
Securities available-for-sale, at fair value	102,261	385,362
Mortgage-backed Securities, Issued by Private Enterprises
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	28,903	453,314
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	147
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2,076)	(3,244)
Securities available-for-sale, at fair value	26,827	450,217
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	23,568	129,387
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	484
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,155)	(324)
Securities available-for-sale, at fair value	22,413	129,547
SBA asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	18,524	28,950
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	726
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,274)	(32)
Securities available-for-sale, at fair value	$ 17,250	$ 29,644