Investment Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	$ 10,694,458	$ 5,235,591
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	163,035	241,999
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(72,095)	(3,378)
Available-for-sale Securities, Amortized Cost Basis	10,603,518	4,996,970
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	2,898,210	341,074
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	8,866	12,483
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(32,649)	(897)
Available-for-sale Securities, Amortized Cost Basis	2,921,993	329,488
Municipal Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	2,315,968	1,531,617
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	75,192	93,631
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(7,973)	(18)
Available-for-sale Securities, Amortized Cost Basis	2,248,749	1,438,004
Government agency and government-sponsored enterprise pass through securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	1,688,967	1,281,877
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	37,664	74,238
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(9,213)	(37)
Available-for-sale Securities, Amortized Cost Basis	1,660,516	1,207,676
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	1,038,134	1,219,880
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	22,288	47,994
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(5,870)	(280)
Available-for-sale Securities, Amortized Cost Basis	1,021,716	1,172,166
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	966,898	5,302
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,641	313
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(8,298)	0
Available-for-sale Securities, Amortized Cost Basis	973,555	4,989
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	527,094	311,889
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	13,774	3,490
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(757)	(404)
Available-for-sale Securities, Amortized Cost Basis	514,077	308,803
Mortgage-backed Securities, Issued by Private Enterprises
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	450,217	82,957
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	147	1,089
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3,244)	(10)
Available-for-sale Securities, Amortized Cost Basis	453,314	81,878
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	385,362	135,876
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	396	23
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(444)	(924)
Available-for-sale Securities, Amortized Cost Basis	385,410	136,777
Private Label Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	264,417	116,946
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,857	6,076
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3,291)	(21)
Available-for-sale Securities, Amortized Cost Basis	265,851	110,891
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	129,547	166,546
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	484	445
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(324)	(760)
Available-for-sale Securities, Amortized Cost Basis	129,387	166,861
SBA asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, at fair value	29,644	41,627
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	726	2,217
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(32)	(27)
Available-for-sale Securities, Amortized Cost Basis	$ 28,950	$ 39,437

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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