Securities Available for Sale and Held to Maturity - Securities with Gross Unrealized Losses, Segregated by Length of Impairment (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]
Estimated Fair Value, Less than 12 Months	$ 1,917,076	$ 2,423,465
Estimated Fair Value, 12 Months or More	1,591,467	67,875
Estimated Fair Value, Total	3,508,543	2,491,340
Gross Unrealized (Losses), Less than 12 Months	(154,783)	(29,552)
Gross Unrealized (Losses), 12 Months or More	(268,317)	(1,406)
Gross Unrealized (Losses), Total	(423,100)	(30,958)
US Treasury Securities [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	158,877	315,123
Estimated Fair Value, 12 Months or More	257,401	0
Estimated Fair Value, Total	416,278	315,123
Gross Unrealized (Losses), Less than 12 Months	(9,333)	(4,938)
Gross Unrealized (Losses), 12 Months or More	(32,864)	0
Gross Unrealized (Losses), Total	(42,197)	(4,938)
U.S. Government Agency Obligations [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	3,088	1,312
Estimated Fair Value, 12 Months or More	5,935	8,619
Estimated Fair Value, Total	9,023	9,931
Gross Unrealized (Losses), Less than 12 Months	(311)	(5)
Gross Unrealized (Losses), 12 Months or More	(254)	(332)
Gross Unrealized (Losses), Total	(565)	(337)
Obligations of States and Political Subdivisions [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	4,763	3,006
Estimated Fair Value, 12 Months or More	3,661	667
Estimated Fair Value, Total	8,424	3,673
Gross Unrealized (Losses), Less than 12 Months	(73)	(1)
Gross Unrealized (Losses), 12 Months or More	(8)	(2)
Gross Unrealized (Losses), Total	(81)	(3)
Residential Mortgage Pass-Through Securities Guaranteed by GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	30,577	6,040
Estimated Fair Value, 12 Months or More	1,199	0
Estimated Fair Value, Total	31,776	6,040
Gross Unrealized (Losses), Less than 12 Months	(4,136)	(37)
Gross Unrealized (Losses), 12 Months or More	(242)	0
Gross Unrealized (Losses), Total	(4,378)	(37)
Residential Mortgage Pass-Through Securities Issued by FNMA and FHLMC [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	562,533	1,734,921
Estimated Fair Value, 12 Months or More	1,315,039	55,303
Estimated Fair Value, Total	1,877,572	1,790,224
Gross Unrealized (Losses), Less than 12 Months	(60,200)	(19,980)
Gross Unrealized (Losses), 12 Months or More	(233,939)	(1,034)
Gross Unrealized (Losses), Total	(294,139)	(21,014)
Other Residential Mortgage-Backed Securities Issued or Guaranteed by FNMA, FHLMC or GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	302,446	19,038
Estimated Fair Value, 12 Months or More	7,610	2,647
Estimated Fair Value, Total	310,056	21,685
Gross Unrealized (Losses), Less than 12 Months	(21,129)	(99)
Gross Unrealized (Losses), 12 Months or More	(1,001)	(29)
Gross Unrealized (Losses), Total	(22,130)	(128)
Commercial Mortgage-Backed Securities Issued or Guaranteed by FNMA, FHLMC or GNMA [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Estimated Fair Value, Less than 12 Months	854,792	344,025
Estimated Fair Value, 12 Months or More	622	639
Estimated Fair Value, Total	855,414	344,664
Gross Unrealized (Losses), Less than 12 Months	(59,601)	(4,492)
Gross Unrealized (Losses), 12 Months or More	(9)	(9)
Gross Unrealized (Losses), Total	$ (59,610)	$ (4,501)