Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	$ 4,251,409	$ 3,749,814
Debt Securities, Available-for-Sale, Unrealized Gain	31,500	24,579
Debt Securities, Available-for-Sale, Unrealized Loss	(130,382)	(173,501)
Debt Securities, Available-for-Sale	4,152,527	3,600,892
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,769,224	3,860,235
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	48,682	55,619
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(465,131)	(535,230)
Debt Securities, Held-to-Maturity, Fair Value	3,352,775	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	39,987	39,984
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(3,039)	(4,083)
Debt Securities, Available-for-Sale	36,948	35,902
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
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(10)	(36)
Debt Securities, Held-to-Maturity, Fair Value	990	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	82,845	94,008
Debt Securities, Available-for-Sale, Unrealized Gain	11	23
Debt Securities, Available-for-Sale, Unrealized Loss	(1,766)	(2,214)
Debt Securities, Available-for-Sale	81,089	91,817
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,664,740	1,682,473
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	4,596	5,638
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(128,987)	(134,053)
Debt Securities, Held-to-Maturity, Fair Value	1,540,348	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
Debt Securities, Available-for-Sale	0
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	329,349	345,083
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	8,519	9,796
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(55,765)	(65,372)
Debt Securities, Held-to-Maturity, Fair Value	282,103	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	113,139	135,832
Debt Securities, Available-for-Sale, Unrealized Gain	132	5
Debt Securities, Available-for-Sale, Unrealized Loss	(922)	(1,862)
Debt Securities, Available-for-Sale	112,350	133,975
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]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	540	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	516	1,051
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Debt Securities, 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	(3)	(50)
Debt Securities, Available-for-Sale	2,997	2,950
US Government Sponsored-Enterprise Insured Loans | Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	1,201,968	1,274,052
Debt Securities, Available-for-Sale, Unrealized Gain	990	294
Debt Securities, Available-for-Sale, Unrealized Loss	(117,544)	(153,552)
Debt Securities, Available-for-Sale	1,085,414	1,120,794
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	900,743	941,973
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	24,025	27,007
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(145,885)	(164,587)
Debt Securities, Held-to-Maturity, Fair Value	778,883	804,393
US Government Sponsored-Enterprise Insured Loans | Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	18,423	18,691
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(388)	(1,755)
Debt Securities, Available-for-Sale	18,035	16,937
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	775,209	780,995
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	11,142	12,699
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(126,498)	(160,781)
Debt Securities, Held-to-Maturity, Fair Value	659,852	632,914
Government National Mortgage Association (GNMA) [Member] | Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	2,634,634	2,021,242
Debt Securities, Available-for-Sale, Unrealized Gain	30,367	24,254
Debt Securities, Available-for-Sale, Unrealized Loss	(1,441)	(2,822)
Debt Securities, Available-for-Sale	2,663,560	2,042,675
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	45,180	48,979
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	143	92
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(2,344)	(2,901)
Debt Securities, Held-to-Maturity, Fair Value	42,979	46,170
Government National Mortgage Association (GNMA) [Member] | Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	156,873	161,928
Debt Securities, Available-for-Sale, Unrealized Gain	0	0
Debt Securities, Available-for-Sale, Unrealized Loss	(5,256)	(7,135)
Debt Securities, Available-for-Sale	151,617	154,793
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	53,005	59,733
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain	258	386
Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss	(5,643)	(7,500)
Debt Securities, Held-to-Maturity, Fair Value	$ 47,620	$ 52,619