Consolidated Statement of Stockholders' Equity - USD ($)		Total	Common Stock [Member]	Shares Of Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Shares, Outstanding at Dec. 31, 2014			103,022,017
Total stockholders' equity at Dec. 31, 2014		$ 3,506,230,000	$ 1,042,000		$ 3,807,167,000	$ (285,712,000)	$ (42,647,000)	$ 26,380,000
Net Income		299,619,000				299,619,000
available-for-sale, net of tax		1,448,000						1,448,000
Stock Issued During Period, Shares, Acquisitions			18,135,845
Issuance of common stock for merger with CapitalSource Inc.		797,433,000	$ 181,000		797,252,000	0	0	0
Restricted stock awarded and earned stock compensation, net of shares forfeited, shares			435,387
net of shares forfeited		15,630,000	$ 5,000		15,625,000
Restricted stock surrendered, shares			(180,822)
Stock Repurchase Program		(8,400,000)					(8,400,000)
Dividend reinvestment, shares			1,300
Dividend reinvestment		58,000			58,000
restricted stock		841,000			841,000
Cash dividends paid		(215,168,000)			(215,168,000)
Total stockholders' equity at Dec. 31, 2015		4,397,691,000	$ 1,228,000		4,405,775,000	13,907,000	(51,047,000)	27,828,000
Shares, Outstanding at Dec. 31, 2015			121,413,727
Net Income		352,166,000				352,166,000
available-for-sale, net of tax		(21,846,000)						(21,846,000)
Restricted stock awarded and earned stock compensation, net of shares forfeited, shares			664,135
net of shares forfeited		$ 23,319,000	$ 7,000		23,312,000
Restricted stock surrendered, shares			(141,358)	(652,835)
Stock Repurchase Program, Number of Shares Authorized to be Repurchased		(7,000)
Stock Repurchase Program		$ (5,313,000)					(5,313,000)
Common Stock Repurchased Under Stock Repurchase Program, Amount Repurchased		(27,931,000)			(27,924,000)		0
restricted stock		4,406,000			4,406,000
Cash dividends paid		(243,437,000)			(243,437,000)
Total stockholders' equity at Dec. 31, 2016		4,479,055,000	$ 1,228,000		4,162,132,000	366,073,000	(56,360,000)	5,982,000
Shares, Outstanding at Dec. 31, 2016			121,283,669
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	[1]	291,000			711,000	(420,000)
Net Income		357,818,000				357,818,000
available-for-sale, net of tax		25,189,000						25,189,000
Stock Issued During Period, Shares, Acquisitions			9,298,451
Issuance of common stock for merger with CapitalSource Inc.		446,233,000	$ 93,000		446,140,000	0	0	0
Restricted stock awarded and earned stock compensation, net of shares forfeited, shares			470,855
net of shares forfeited		$ 25,568,000	$ 5,000		25,563,000
Restricted stock surrendered, shares			(188,870)	(2,081,227)
Stock Repurchase Program, Number of Shares Authorized to be Repurchased		(21,000)
Stock Repurchase Program		$ (9,476,000)					(9,476,000)
Common Stock Repurchased Under Stock Repurchase Program, Amount Repurchased		(99,677,000)			(99,656,000)		0
Cash dividends paid		(247,403,000)			(247,403,000)
Total stockholders' equity at Dec. 31, 2017		$ 4,977,598,000	$ 1,305,000		$ 4,287,487,000	723,471,000	$ (65,836,000)	$ 31,171,000
Shares, Outstanding at Dec. 31, 2017			128,782,878
Cumulative Effect of New Accounting Principle in Period of Adoption						$ (420,000)

[1] Impact due to adoption on January 1, 2017 of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting."