CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Series A	Preferred Series B	Common stock	Preferred Stock	Common stock	Surplus	Retained Earnings	Retained Earnings Preferred Series A	Retained Earnings Preferred Series B	Retained Earnings Common stock	Accumulated Other Comprehensive Loss	Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment due to adoption of ASUs | ASU 2016-02	$ 4,414							$ 4,414
Adjustment due to adoption of ASUs | ASU 2017-08	(1,446)							(1,446)
Beginning Balance, adjusted	3,353,422				$ 209,691	$ 116,240	$ 2,796,499	302,610				$ (69,431)	$ (2,187)
Beginning balance at Dec. 31, 2018	3,350,454				209,691	$ 116,240	2,796,499	299,642				(69,431)	(2,187)
Beginning balance (in shares) at Dec. 31, 2018						331,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	113,330							113,330
Other comprehensive income, net of tax	16,174											16,174
Cash dividends declared:
Cash dividends declared on preferred stock		$ (1,797)	$ (1,375)						$ (1,797)	$ (1,375)
Cash dividends declared on common stock				$ (36,686)							$ (36,686)
Effect of stock incentive plan, net (in shares)						302
Effect of stock incentive plan, net	1,811					$ 226	2,935	(99)					(1,251)
Ending balance at Mar. 31, 2019	3,444,879				209,691	$ 116,466	2,799,434	375,983				(53,257)	(3,438)
Ending balance (in shares) at Mar. 31, 2019						331,733
Beginning balance at Dec. 31, 2018	3,350,454				209,691	$ 116,240	2,796,499	299,642				(69,431)	(2,187)
Beginning balance (in shares) at Dec. 31, 2018						331,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	189,798
Ending balance at Jun. 30, 2019	3,504,118				209,691	$ 116,571	2,804,059	412,190				(35,131)	(3,262)
Ending balance (in shares) at Jun. 30, 2019						331,788
Beginning balance at Mar. 31, 2019	3,444,879				209,691	$ 116,466	2,799,434	375,983				(53,257)	(3,438)
Beginning balance (in shares) at Mar. 31, 2019						331,733
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	76,468							76,468
Other comprehensive income, net of tax	18,126											18,126
Cash dividends declared:
Cash dividends declared on preferred stock		(1,797)	(1,375)						(1,797)	(1,375)
Cash dividends declared on common stock				(36,712)							(36,712)
Effect of stock incentive plan, net (in shares)						55
Effect of stock incentive plan, net	4,529					$ 105	4,625	(377)					176
Ending balance at Jun. 30, 2019	3,504,118				209,691	$ 116,571	2,804,059	412,190				(35,131)	(3,262)
Ending balance (in shares) at Jun. 30, 2019						331,788
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment due to adoption of ASUs | ASU 2016-13	(28,187)							(28,187)
Beginning Balance, adjusted	4,356,001				209,691	$ 141,423	3,622,208	415,372				(32,214)	(479)
Beginning balance at Dec. 31, 2019	4,384,188				209,691	$ 141,423	3,622,208	443,559				(32,214)	(479)
Beginning balance (in shares) at Dec. 31, 2019						403,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	87,268							87,268
Other comprehensive income, 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				209,691	$ 141,423	3,622,208	443,559				(32,214)	(479)
Beginning balance (in shares) at Dec. 31, 2019						403,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	182,869
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
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, 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