Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands		Total	Preferred Equity	Common Stock [Member]	Surplus	Retained Earnings	Retained Earnings Series C Preferred Stock	Retained Earnings Series D Preferred Stock	Retained Earnings Series E Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2016		$ 3,091,312	$ 159,929	$ 1,630	$ 1,364,066	$ 1,791,196				$ (54,679)	$ (170,830)
Preferred stock shares outstanding, beginning balance (in shares) at Dec. 31, 2016			165,000
Common stock shares outstanding, beginning balance (in shares) at Dec. 31, 2016				163,030,000
Comprehensive income:
Net income		229,264				229,264
Other comprehensive loss		(8,079)								(8,079)
Comprehensive income		221,185
Common stock issued:
Stock-based compensation plans, net		27,619			(17,737)	0					45,356
Common Stock Issued During Period, Shares, Acquisitions				291,000
Issuance of treasury stock for acquisition		7,151		$ 3	7,148						0
Purchase of common stock returned to authorized but unissued, shares				(1,569,000)
Purchase of common stock returned to authorized but unissued, amount		(37,031)		$ (15)	(37,016)
Purchase of treasury stock		(9,290)									(9,290)
Cash dividends
Common stock dividends		(76,417)				(76,417)
Preferred stock dividends	[1]	(9,347)				(9,347)
Stock-based compensation expense, net		21,227			21,227
Tax impact of stock-based compensation		1,034			1,034
Ending balance at Dec. 31, 2017		3,237,443	$ 159,929	$ 1,618	1,338,722	1,934,696				(62,758)	(134,764)
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2017			165,000
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2017				161,752,000
Cash dividends
Preferred Stock, Dividends, Per Share, Cash Paid							$ 1.53125	$ 1.34375
Net income		333,562				333,562
Other comprehensive loss		(62,214)								(62,214)
Other Comprehensive Income, Other, Net of Tax		(48,476)								(48,476)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(13,738)								(13,738)
Comprehensive income		271,348
Stock-based compensation plans, net		18,408			(7,116)	15,096					10,428
Common Stock Issued During Period, Shares, Acquisitions				13,705,000
Issuance of treasury stock for acquisition		488,408		$ 137	396,975						91,296
Purchase of common stock returned to authorized but unissued, shares				(1,357,000)
Purchase of common stock returned to authorized but unissued, amount		(33,075)		$ (14)	(33,061)
Purchase of treasury stock		(213,598)									(213,598)
Common stock dividends		(105,519)				(105,519)
Preferred stock dividends	[2]	(10,784)				(10,784)
Issuance of preferred stock			100,000
Issuance of preferred stock		97,315	$ 97,315
Purchase of Preferred Stock Repurchased During Period, Shares			(1,000)
Purchase of preferred stock		(537)	$ (528)			(8)
Common Stock Shares from Warrant Exercises				1,116,000
Proceeds from Common Stock Warrant Exercises		(1)		$ 11	(12)
Stock-based compensation expense, net		17,107			17,107
Tax Act Reclassification		13,654				13,654
Change in Accounting Principal		84				84
Other		632				632
Ending balance at Dec. 31, 2018		$ 3,780,888	$ 256,716	$ 1,752	1,712,615	2,181,414				(124,972)	(246,638)
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2018			264,000
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2018		164,440,471		175,216,000
Cash dividends
Preferred Stock, Dividends, Per Share, Cash Paid							1.53125	1.34375	$ 0.322309
Net income		$ 326,790				326,790
Other comprehensive loss		91,789								91,789
Comprehensive income		418,579
Stock-based compensation plans, net		11,216			(21,038)	0					32,254
Purchase of treasury stock		(186,076)									(186,076)
Common stock dividends		(111,804)				(111,804)
Preferred stock dividends	[3]	(15,202)				(15,202)
Stock-based compensation expense, net		24,854			24,854
Other		(331)				(331)
Ending balance at Dec. 31, 2019		$ 3,922,124	$ 256,716	$ 1,752	$ 1,716,431	$ 2,380,867				$ (33,183)	$ (400,460)
Preferred stock shares outstanding, ending balance (in shares) at Dec. 31, 2019			264,000
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2019		157,171,247		175,216,000
Cash dividends
Preferred Stock, Dividends, Per Share, Cash Paid							$ 1.53125	$ 1.34375	$ 1.46875

[1] (a) Series C, $1.53125 per share; and Series D, $1.34375 per share.

[2] (b) Series C, $1.53125 per share; Series D, $1.34375 per share; and Series E, $0.322309 per share.

[3] (c) Series C, $1.53125 per share; Series D, $1.34375 per share; and Series E, $1.46875 per share.