Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total	Preferred Equity	Common Stock	Surplus	Retained Earnings	AOCI Allocated to Parent [Member]	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2015		$ 2,937,246	$ 121,379	$ 1,642	$ 1,382,446	$ 1,669,315		$ (32,616)	$ (204,920)
Preferred stock shares outstanding, beginning balance (in shares) at Dec. 31, 2015			125
Common stock shares outstanding, beginning balance (in shares) at Dec. 31, 2015				164,200
Comprehensive income:
Net income		200,274	$ 0	$ 0	0	200,274		0	0
Other comprehensive loss		(22,063)	0	0	0	0		(22,063)	0
Comprehensive income		178,211
Common stock issued:
Stock-based compensation plans, net	[1]	21,748	$ 0	$ 0	(17,416)	0		0	39,164
Purchase of common stock returned to authorized but unissued			0	(1,170)
Purchase of common stock returned to authorized but unissued		(20,007)	$ 0	$ (12)	(19,995)	0		0	0
Purchase of treasury stock		(5,074)	0	0	0	0		0	(5,074)
Cash dividends
Common stock dividends		(67,855)	0	0	0	(67,855)		0	0
Preferred stock dividends		(8,903)	$ 0	$ 0	0	(8,903)		0	0
Issuance of preferred stock			100	0
Issuance of preferred stock		97,066	$ 97,066	$ 0	0	0		0	0
Redemption of preferred stock			(60)	0
Redemption of preferred stock		(58,903)	$ (57,338)	$ 0	0	(1,565)		0	0
Purchase of preferred stock			0	0
Purchase of preferred stock		(1,248)	$ (1,178)	$ 0	0	(70)		0	0
Stock-based compensation expense, net		21,971	0	0	21,971	0		0	0
Tax impact of stock-based compensation		(2,940)	0	0	(2,940)	0		0	0
Ending 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, ending balance (in shares) at Dec. 31, 2016			165
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2016				163,030
Net Adjustment, Stock-based Compensation Plans, warrants, options, RSU/A						76,000
Comprehensive income:
Net income		229,264	$ 0	$ 0	0	229,264		0	0
Other comprehensive loss		(8,079)	0	0	0	0		(8,079)	0
Comprehensive income		221,185
Common stock issued:
Stock-based compensation plans, net	[1]	27,619	$ 0	$ 0	(17,737)	0		0	45,356
Stock Issued During Period, Shares, Acquisitions			0	291
Stock Issued During Period, Value, Acquisitions		7,151	$ 0	$ 3	7,148	0		0	0
Purchase of common stock returned to authorized but unissued			0	(1,569)
Purchase of common stock returned to authorized but unissued		(37,031)	$ 0	$ (15)	(37,016)	0		0	0
Purchase of treasury stock		(9,290)	0	0	0	0		0	(9,290)
Cash dividends
Common stock dividends		(76,417)	0	0	0	(76,417)		0	0
Preferred stock dividends		(9,347)	0	0	0	(9,347)		0	0
Stock-based compensation expense, net		21,227	0	0	21,227	0		0	0
Tax impact of stock-based compensation		1,034	0	0	1,034	0		0	0
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
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2017				161,752
Net Adjustment, Stock-based Compensation Plans, warrants, options, RSU/A	[2]	115,000
Comprehensive income:
Net income		333,562	$ 0	$ 0	0	333,562		0	0
Other comprehensive loss		(62,214)						(62,214)
Other Comprehensive Income, Other, Net of Tax		(48,476)	0	0	0	0		(48,476)	0
Adoption of new accounting standards		(13,738)	0	0	0	0		(13,738)	0
Comprehensive income		271,348
Common stock issued:
Stock-based compensation plans, net	[1]	18,408	$ 0	$ 0	(7,116)	15,096		0	10,428
Stock Issued During Period, Shares, Acquisitions			0	13,705
Stock Issued During Period, Value, Acquisitions		488,408	$ 0	$ 137	396,975	0		0	91,296
Purchase of common stock returned to authorized but unissued			0	(1,357)
Purchase of common stock returned to authorized but unissued		(33,075)	$ 0	$ (14)	(33,061)	0		0	0
Purchase of treasury stock		(213,598)	0	0	0	0		0	(213,598)
Cash dividends
Common stock dividends		(105,519)	0	0	0	(105,519)		0	0
Preferred stock dividends		(10,784)	$ 0	$ 0	0	(10,784)		0	0
Issuance of preferred stock			100	0
Issuance of preferred stock		97,315	$ 97,315	$ 0	0	0		0	0
Purchase of preferred stock			(1)	0
Purchase of preferred stock		(537)	$ (528)	$ 0	0	(8)		0	0
Shares from Warrant Exercises			0	1,116
Proceeds from Warrant Exercises		(1)	$ 0	$ 11	(12)	0		0	0
Stock-based compensation expense, net		17,107	0	0	17,107	0		0	0
Tax Act Reclassification		13,654	0	0	0	13,654		0	0
Change in Equity Securities(2016-01)		84	$ 0	$ 0	0	84	$ 0	(84)	0
Other			0	0
Other		632	$ 0	$ 0	0	632		0	0
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
Common stock shares outstanding, ending balance (in shares) at Dec. 31, 2018				175,216

[1] bers may not sum due to rounding. (a) An adjustment of $76 million was made within stockholders' equity related to the grant and vesting of options, restricted stock awards, and restricted stock units awarded from 2006-2015 to the December 31, 2015 ending balances.  In addition, within the Statement of Stockholders' Equity, Stock-based compensation plans, net was adjusted for years 2016-2018.  This adjustment impacted Retained Earnings and Surplus.  The reclassification had no impact on earnings, ex

[2] An adjustment of $115 million was made within the December 31, 2017 stockholders' equity balances related to the grant and vesting of options, restricted stock awards, and restricted stock units awarded from 2006-2017.  This adjustment impacted Retained Earnings and Surplus.  The reclassification had no impact on earnings, expenses, or total stockholder’s equity.