Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands	Total	Preferred Stock	Common Stock	Common Stock Warrant	Capital Surplus	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Beginning Balance at Dec. 31, 2010	$ 1,507,715	$ 0	$ 127,937	$ 0	$ 485,567	$ (26,103)	$ 1,080,900	$ (160,586)
Net income	57,324	0	0	0	0	0	57,324	0
Cash dividends - common stock	34,616						34,616	0
Nonvested (restricted) shares granted	1				(13,656)	0	0	13,657
Restricted stock activity	(2,223)				312	0	0	(2,535)
Deferred compensation trust	0				(2)	0	0	2
Share-based compensation	5,228				5,228	0	0	0
Net unrealized gains on investment securities, net of taxes	16,958	0	0	0	0	16,958	0	0
Ending Balance at Jun. 30, 2011	1,550,387	0	127,937	0	477,449	(9,145)	1,103,608	(149,462)
Beginning Balance at Dec. 31, 2011	1,565,953	0	127,937	0	479,882	(23,887)	1,131,203	(149,182)
Net income	60,929	0	0	0	0	0	60,929	0
Cash dividends - common stock	34,710						34,710	0
Nonvested (restricted) shares granted	0				(14,079)	0	0	14,079
Restricted stock activity	(2,278)				966	0	0	(3,244)
Deferred compensation trust	0				(90)	0	0	90
Share-based compensation	5,410				5,410	0	0	0
Net unrealized gains on investment securities, net of taxes	5,462	0	0	0	0	5,462	0	0
Other capital surplus	49				49
Ending Balance at Jun. 30, 2012	$ 1,600,815	$ 0	$ 127,937	$ 0	$ 472,138	$ (18,425)	$ 1,157,422	$ (138,257)