Consolidated Statement of Shareholders' Equity - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2014	$ 3,506,230	$ 1,042	$ 3,807,167	$ (285,712)	$ (42,647)	$ 26,380
Shares outstanding, beginning balance (shares) at Dec. 31, 2014		103,022,017
Stockholders' Equity Disclosure [Rollforward]
Net earnings	227,778			227,778
Other comprehensive loss-net unrealized loss on securities available-for-sale, net of tax	(1,921)	$ 0	0	0	0	(1,921)
Restricted stock awarded and earned stock compensation, net of shares forfeited	11,836	$ 2	11,834	0	0	0
Restricted stock awarded and earned compensation, net of shares forfeited (shares)		211,011
Restricted stock surrendered	(8,391)	$ 0	0	0	(8,391)	0
Restricted stock surrendered (shares)		(180,634)
Tax effect from vesting of restricted stock	596	$ 0	596	0	0	0
Cash dividends paid	(154,482)	0	(154,482)	0	0	0
Dividend reinvestment	58	$ 0	58	0	0	0
Dividend reinvestment (shares)		1,300
Ending Balance at Sep. 30, 2015	$ 3,581,704	$ 1,044	$ 3,665,173	$ (57,934)	$ (51,038)	$ 24,459
Shares outstanding, ending balance (shares) at Sep. 30, 2015		103,053,694