Consolidated Statement of Shareholders' Equity - 6 months ended Jun. 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	158,162			158,162
Other comprehensive loss-net unrealized loss on securities available-for-sale, net of tax	(10,125)	$ 0	0	0	0	(10,125)
Restricted stock awarded and earned stock compensation, net of shares forfeited	8,074	$ 2	8,072	0	0	0
Restricted stock awarded and earned compensation, net of shares forfeited (shares)		208,112
Restricted stock surrendered	(8,336)	$ 0	0	0	(8,336)	0
Restricted stock surrendered (shares)		(179,439)
Tax effect from vesting of restricted stock	401	$ 0	401	0	0	0
Cash dividends paid	(102,974)	0	(102,974)	0	0	0
Dividend reinvestment	58	$ 0	58	0	0	0
Dividend reinvestment (shares)		1,300
Ending Balance at Jun. 30, 2015	$ 3,551,490	$ 1,044	$ 3,712,724	$ (127,550)	$ (50,983)	$ 16,255
Shares outstanding, ending balance (shares) at Jun. 30, 2015		103,051,990