Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	$ 4,605,954	$ 3,749,814
Debt Securities, Available-for-Sale, Unrealized Gain	5,693	24,579
Debt Securities, Available-for-sale, Unrealized Loss	(30,213)	(173,501)
Debt Securities, Available-for-sale	4,581,434	3,600,892
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,738,747	3,860,235
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	42,653	55,619
Held-to-maturity, Gross Unrealized Loss	(595,906)	(535,230)
Debt Securities, Held-to-Maturity, Fair Value	3,185,494	3,380,624
US Treasury Securities [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost		39,984
Debt Securities, Available-for-Sale, Unrealized Gain		0
Debt Securities, Available-for-sale, Unrealized Loss		(4,083)
Debt Securities, Available-for-sale		35,902
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,000	999
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	0	0
Held-to-maturity, Gross Unrealized Loss	(1)	(36)
Debt Securities, Held-to-Maturity, Fair Value	999	963
US States and Political Subdivisions Debt Securities [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	3,063	94,008
Debt Securities, Available-for-Sale, Unrealized Gain	0	23
Debt Securities, Available-for-sale, Unrealized Loss	(58)	(2,214)
Debt Securities, Available-for-sale	3,005	91,817
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,659,722	1,682,473
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	1,122	5,638
Held-to-maturity, Gross Unrealized Loss	(174,202)	(134,053)
Debt Securities, Held-to-Maturity, Fair Value	1,486,642	1,554,059
Residential Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	120,272	1,274,052
Debt Securities, Available-for-Sale, Unrealized Gain	190	294
Debt Securities, Available-for-sale, Unrealized Loss	(9,534)	(153,552)
Debt Securities, Available-for-sale	110,928	1,120,794
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	885,476	941,973
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	22,934	27,007
Held-to-maturity, Gross Unrealized Loss	(186,464)	(164,587)
Debt Securities, Held-to-Maturity, Fair Value	721,946	804,393
Residential Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	4,236,199	2,021,242
Debt Securities, Available-for-Sale, Unrealized Gain	5,379	24,254
Debt Securities, Available-for-sale, Unrealized Loss	(13,851)	(2,822)
Debt Securities, Available-for-sale	4,227,727	2,042,675
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	43,693	48,979
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	9	92
Held-to-maturity, Gross Unrealized Loss	(3,774)	(2,901)
Debt Securities, Held-to-Maturity, Fair Value	39,927	46,170
Commercial Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	18,332	18,691
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(1,332)	(1,755)
Debt Securities, Available-for-sale	17,000	16,937
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	772,456	780,995
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	10,217	12,699
Held-to-maturity, Gross Unrealized Loss	(159,078)	(160,781)
Debt Securities, Held-to-Maturity, Fair Value	623,595	632,914
Commercial Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	116,275	161,928
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(4,800)	(7,135)
Debt Securities, Available-for-sale	111,475	154,793
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	52,219	59,733
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	236	386
Held-to-maturity, Gross Unrealized Loss	(6,424)	(7,500)
Debt Securities, Held-to-Maturity, Fair Value	46,032	52,619
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	0
Debt Securities, Available-for-sale	0
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	324,182	345,083
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	8,135	9,796
Held-to-maturity, Gross Unrealized Loss	(65,963)	(65,372)
Debt Securities, Held-to-Maturity, Fair Value	266,353	289,507
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	108,319	135,832
Debt Securities, Available-for-Sale, Unrealized Gain	123	5
Debt Securities, Available-for-sale, Unrealized Loss	(604)	(1,862)
Debt Securities, Available-for-sale	107,839	133,975
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
US Government-sponsored Enterprises Debt Securities [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	495	1,077
Debt Securities, Available-for-Sale, Unrealized Gain	0	2
Debt Securities, Available-for-sale, Unrealized Loss	(24)	(28)
Debt Securities, Available-for-sale	471	1,051
HTM investment securities
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, Held-to-Maturity, Fair Value	0
Other Debt Obligations [Member]
AFS investment securities
Debt Securities, Available-for-Sale, Amortized Cost	3,000	3,000
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(11)	(50)
Debt Securities, Available-for-sale	$ 2,989	$ 2,950