Investment Securities, AFS and HTM Securities Amortized Costs and Fair Values (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,762,393	$ 4,338,671
Debt Securities, Available-for-sale, Unrealized Gain	461	28,850
Debt Securities, Available-for-sale, Unrealized Loss	(275,542)	(35,506)
Debt Securities, Available-for-sale	2,487,312	4,332,015
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	3,951,553	2,239,003
Held-to-maturity, Gross Unrealized Gains	61,791	118,471
Held-to-maturity, Gross Unrealized Loss	(717,582)	(8,809)
Held-to-maturity, Fair Value	3,295,760	2,348,664
US Treasury Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	124,403	124,291
Debt Securities, Available-for-sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(16,119)	(1,334)
Debt Securities, Available-for-sale	108,284	122,957
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	998	1,000
Held-to-maturity, Gross Unrealized Gains	0	1
Held-to-maturity, Gross Unrealized Loss	(66)	0
Held-to-maturity, Fair Value	932	1,001
Agency Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	15,000	15,000
Debt Securities, Available-for-sale, Unrealized Gain	0	0
Debt Securities, Available-for-sale, Unrealized Loss	(1,601)	(103)
Debt Securities, Available-for-sale	13,399	14,897
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	356,539	381,517
Debt Securities, Available-for-sale, Unrealized Gain	28	18,940
Debt Securities, Available-for-sale, Unrealized Loss	(15,669)	0
Debt Securities, Available-for-sale	340,898	400,457
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,737,135	1,628,759
Held-to-maturity, Gross Unrealized Gains	273	113,179
Held-to-maturity, Gross Unrealized Loss	(272,360)	(1,951)
Held-to-maturity, Fair Value	1,465,048	1,739,988
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	332,028
Debt Securities, Available-for-sale, Unrealized Gain		31
Debt Securities, Available-for-sale, Unrealized Loss		(2,335)
Debt Securities, Available-for-sale	0	329,724
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	369,711
Held-to-maturity, Gross Unrealized Gains	12,167
Held-to-maturity, Gross Unrealized Loss	(74,906)
Held-to-maturity, Fair Value	306,972
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	163,314	177,974
Debt Securities, Available-for-sale, Unrealized Gain	0	475
Debt Securities, Available-for-sale, Unrealized Loss	(4,757)	(1,123)
Debt Securities, Available-for-sale	158,556	177,325
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	4,797	6,594
Debt Securities, Available-for-sale, Unrealized Gain	20	39
Debt Securities, Available-for-sale, Unrealized Loss	(45)	(54)
Debt Securities, Available-for-sale	4,772	6,580
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	(67)	(6)
Debt Securities, Available-for-sale	2,933	2,994
FNMA/FHLMC \| Residential Related Securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,882,668	2,709,399
Debt Securities, Available-for-sale, Unrealized Gain	413	3,729
Debt Securities, Available-for-sale, Unrealized Loss	(227,020)	(21,249)
Debt Securities, Available-for-sale	1,656,061	2,691,879
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	961,946	34,347
Held-to-maturity, Gross Unrealized Gains	32,561	1,792
Held-to-maturity, Gross Unrealized Loss	(182,409)	0
Held-to-maturity, Fair Value	812,099	36,139
FNMA/FHLMC \| Commercial mortgage-related securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	19,123	357,240
Debt Securities, Available-for-sale, Unrealized Gain	0	2,686
Debt Securities, Available-for-sale, Unrealized Loss	(1,837)	(9,302)
Debt Securities, Available-for-sale	17,286	350,623
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	762,377	425,937
Held-to-maturity, Gross Unrealized Gains	16,045	122
Held-to-maturity, Gross Unrealized Loss	(176,822)	(6,659)
Held-to-maturity, Fair Value	601,600	419,400
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	82,263	66,189
Debt Securities, Available-for-sale, Unrealized Gain	0	1,591
Debt Securities, Available-for-sale, Unrealized Loss	(4,234)	0
Debt Securities, Available-for-sale	78,029	67,780
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	43,168	48,053
Held-to-maturity, Gross Unrealized Gains	27	1,578
Held-to-maturity, Gross Unrealized Loss	(3,872)	0
Held-to-maturity, Fair Value	39,323	49,631
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	111,286	165,439
Debt Securities, Available-for-sale, Unrealized Gain	0	1,360
Debt Securities, Available-for-sale, Unrealized Loss	(4,192)	0
Debt Securities, Available-for-sale	107,094	166,799
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	76,217	100,907
Held-to-maturity, Gross Unrealized Gains	716	1,799
Held-to-maturity, Gross Unrealized Loss	(7,147)	(200)
Held-to-maturity, Fair Value	$ 69,787	$ 102,506

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