Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 4,102,470	$ 3,749,814
Debt Securities, Available-for-sale, Unrealized Gain	3,941	24,579
Debt Securities, Available-for-sale, Unrealized Loss	(193,681)	(173,501)
AFS investment securities, at fair value	3,912,730	3,600,892
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,799,119	3,860,235
Held-to-maturity, Gross Unrealized Gains	47,119	55,619
Held-to-maturity, Gross Unrealized Loss	(599,286)	(535,230)
Held-to-maturity, Fair Value	3,246,952	3,380,624
US Treasury Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	39,986	39,984
Debt Securities, Available-for-sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(4,349)	(4,083)
AFS investment securities, at fair value	35,638	35,902
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,000	999
Held-to-maturity, Gross Unrealized Gains	0	0
Held-to-maturity, Gross Unrealized Loss	(22)	(36)
Held-to-maturity, Fair Value	978	963
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	82,876	94,008
Debt Securities, Available-for-sale, Unrealized Gain	0	23
Debt Securities, Available-for-sale, Unrealized Loss	(4,369)	(2,214)
AFS investment securities, at fair value	78,507	91,817
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,668,494	1,682,473
Held-to-maturity, Gross Unrealized Gains	1,411	5,638
Held-to-maturity, Gross Unrealized Loss	(172,235)	(134,053)
Held-to-maturity, Fair Value	1,497,670	1,554,059
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	0
AFS investment securities, at fair value	0
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	335,148	345,083
Held-to-maturity, Gross Unrealized Gains	8,955	9,796
Held-to-maturity, Gross Unrealized Loss	(70,211)	(65,372)
Held-to-maturity, Fair Value	273,892	289,507
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	123,720	135,832
Debt Securities, Available-for-sale, Unrealized Gain	43	5
Debt Securities, Available-for-sale, Unrealized Loss	(998)	(1,862)
AFS investment securities, at fair value	122,765	133,975
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Held-to-maturity, Fair Value	0
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	667	1,077
Debt Securities, Available-for-sale, Unrealized Gain	0	2
Debt Securities, Available-for-sale, Unrealized Loss	(27)	(28)
AFS investment securities, at fair value	640	1,051
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Held-to-maturity, Fair Value	0
Other Debt securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
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	(27)	(50)
AFS investment securities, at fair value	2,973	2,950
US Government Sponsored-Enterprise Insured Loans | Residential Related Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,224,824	1,274,052
Debt Securities, Available-for-sale, Unrealized Gain	172	294
Debt Securities, Available-for-sale, Unrealized Loss	(160,678)	(153,552)
AFS investment securities, at fair value	1,064,318	1,120,794
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	916,966	941,973
Held-to-maturity, Gross Unrealized Gains	25,024	27,007
Held-to-maturity, Gross Unrealized Loss	(188,333)	(164,587)
Held-to-maturity, Fair Value	753,657	804,393
US Government Sponsored-Enterprise Insured Loans | Commercial mortgage-related securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	18,513	18,691
Debt Securities, Available-for-sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(1,230)	(1,755)
AFS investment securities, at fair value	17,283	16,937
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	776,717	780,995
Held-to-maturity, Gross Unrealized Gains	11,429	12,699
Held-to-maturity, Gross Unrealized Loss	(157,363)	(160,781)
Held-to-maturity, Fair Value	630,783	632,914
Government National Mortgage Association (GNMA) [Member] | Residential Related Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,450,628	2,021,242
Debt Securities, Available-for-sale, Unrealized Gain	3,725	24,254
Debt Securities, Available-for-sale, Unrealized Loss	(13,545)	(2,822)
AFS investment securities, at fair value	2,440,808	2,042,675
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	46,392	48,979
Held-to-maturity, Gross Unrealized Gains	11	92
Held-to-maturity, Gross Unrealized Loss	(3,866)	(2,901)
Held-to-maturity, Fair Value	42,536	46,170
Government National Mortgage Association (GNMA) [Member] | Commercial mortgage-related securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	158,257	161,928
Debt Securities, Available-for-sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(8,458)	(7,135)
AFS investment securities, at fair value	149,799	154,793
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	54,403	59,733
Held-to-maturity, Gross Unrealized Gains	289	386
Held-to-maturity, Gross Unrealized Loss	(7,256)	(7,500)
Held-to-maturity, Fair Value	$ 47,436	$ 52,619