CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Series A	Preferred Series B	Common Stock	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Surplus	Surplus Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Preferred Series A	Retained Earnings Preferred Series B	Retained Earnings Common Stock	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning balance at Dec. 31, 2019	$ 4,384,188				$ (28,187)	$ 4,356,001	$ 209,691	$ 209,691	$ 141,423	$ 141,423	$ 3,622,208	$ 3,622,208	$ 443,559				$ (28,187)	$ 415,372	$ (32,214)	$ (32,214)	$ (479)	$ (479)
Beginning balance (in shares) at Dec. 31, 2019									403,278	403,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	87,268												87,268
Other comprehensive income (loss), net of tax	25,648																		25,648
Cash dividends declared:
Cash dividends declared on preferred stock		$ (1,797)	$ (1,375)											$ (1,797)	$ (1,375)
Cash dividends declared on common stock				$ (44,979)												$ (44,979)
Effect of stock incentive plan, net (in shares)									466
Effect of stock incentive plan, net	232								$ 190		1,828		(2,065)								279
Ending balance at Mar. 31, 2020	4,420,998						209,691		$ 141,613		3,624,036		452,424						(6,566)		(200)
Ending balance (in shares) at Mar. 31, 2020									403,744
Beginning balance at Dec. 31, 2019	4,384,188				$ (28,187)	$ 4,356,001	209,691	$ 209,691	$ 141,423	$ 141,423	3,622,208	$ 3,622,208	443,559				$ (28,187)	$ 415,372	(32,214)	$ (32,214)	(479)	$ (479)
Beginning balance (in shares) at Dec. 31, 2019									403,278	403,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	285,243
Ending balance at Sep. 30, 2020	4,533,763						209,691		$ 141,718		3,633,321		553,826						(4,783)		(10)
Ending balance (in shares) at Sep. 30, 2020									403,879
Beginning balance at Mar. 31, 2020	4,420,998						209,691		$ 141,613		3,624,036		452,424						(6,566)		(200)
Beginning balance (in shares) at Mar. 31, 2020									403,744
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	95,601												95,601
Other comprehensive income (loss), net of tax	1,628																		1,628
Cash dividends declared:
Cash dividends declared on preferred stock		(1,797)	(1,375)											(1,797)	(1,375)
Cash dividends declared on common stock				(44,750)												(44,750)
Effect of stock incentive plan, net (in shares)									52
Effect of stock incentive plan, net	4,183								$ 54		4,756		(592)								(35)
Ending balance at Jun. 30, 2020	4,474,488						209,691		$ 141,667		3,628,792		499,511						(4,938)		(235)
Ending balance (in shares) at Jun. 30, 2020									403,796
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	102,374												102,374
Other comprehensive income (loss), net of tax	155																		155
Cash dividends declared:
Cash dividends declared on preferred stock		(1,797)	(1,375)											(1,797)	(1,375)
Cash dividends declared on common stock				(44,770)												(44,770)
Effect of stock incentive plan, net (in shares)									83
Effect of stock incentive plan, net	4,688								$ 51		4,529		(117)								225
Ending balance at Sep. 30, 2020	4,533,763						209,691		$ 141,718		3,633,321		553,826						(4,783)		(10)
Ending balance (in shares) at Sep. 30, 2020									403,879
Beginning balance at Dec. 31, 2020	4,592,120						209,691		$ 141,746		3,637,468		611,158						(7,718)		(225)
Beginning balance (in shares) at Dec. 31, 2020									403,859
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	115,710												115,710
Other comprehensive income (loss), net of tax	(9,287)																		(9,287)
Cash dividends declared:
Cash dividends declared on preferred stock		(1,797)	(1,375)											(1,797)	(1,375)
Cash dividends declared on common stock				(45,281)												(45,281)
Effect of stock incentive plan, net (in shares)									1,939
Effect of stock incentive plan, net	9,580								$ 689		14,480		(5,764)								175
Ending balance at Mar. 31, 2021	4,659,670						209,691		$ 142,435		3,651,948		672,651						(17,005)		(50)
Ending balance (in shares) at Mar. 31, 2021									405,798
Beginning balance at Dec. 31, 2020	4,592,120						209,691		$ 141,746		3,637,468		611,158						(7,718)		(225)
Beginning balance (in shares) at Dec. 31, 2020									403,859
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	358,802
Ending balance at Sep. 30, 2021	4,822,498						209,691		$ 142,976		3,672,467		818,780						(21,375)		(41)
Ending balance (in shares) at Sep. 30, 2021									407,314
Beginning balance at Mar. 31, 2021	4,659,670						209,691		$ 142,435		3,651,948		672,651						(17,005)		(50)
Beginning balance (in shares) at Mar. 31, 2021									405,798
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	120,512												120,512
Other comprehensive income (loss), net of tax	(730)																		(730)
Cash dividends declared:
Cash dividends declared on preferred stock		(1,797)	(1,375)											(1,797)	(1,375)
Cash dividends declared on common stock				(45,093)												(45,093)
Effect of stock incentive plan, net (in shares)									286
Effect of stock incentive plan, net	6,620								$ 115		6,688		(130)								(53)
Ending balance at Jun. 30, 2021	4,737,807						209,691		$ 142,550		3,658,636		744,768						(17,735)		(103)
Ending balance (in shares) at Jun. 30, 2021									406,084
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	122,580												122,580
Other comprehensive income (loss), net of tax	(3,640)																		(3,640)
Cash dividends declared:
Cash dividends declared on preferred stock		$ (1,797)	$ (1,375)											$ (1,797)	$ (1,375)
Cash dividends declared on common stock				$ (45,228)												$ (45,228)
Effect of stock incentive plan, net (in shares)									1,230
Effect of stock incentive plan, net	14,151								$ 426		13,831		(168)								62
Ending balance at Sep. 30, 2021	$ 4,822,498						$ 209,691		$ 142,976		$ 3,672,467		$ 818,780						$ (21,375)		$ (41)
Ending balance (in shares) at Sep. 30, 2021									407,314