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, 2009
Net income	$ 27,560	$ 0	$ 0	$ 0	$ 0	$ 0	$ 27,560	$ 0
Ending Balance at Dec. 31, 2010	1,507,715	0	127,937	0	485,567	(26,103)	1,080,900	(160,586)
Net income	27,560
Cash dividends - common stock	17,300						17,300	0
Nonvested (restricted) shares granted	0				(171)	0	0	171
Restricted stock activity	(1,557)				139	0	0	(1,696)
Deferred compensation trust	0				34	0	0	(34)
Share-based compensation	3,201				3,201	0	0	0
Net unrealized gains on investment securities, net of taxes	338	0	0	0	0	338	0	0
Ending Balance at Mar. 31, 2011	1,519,957	0	127,937	0	488,770	(25,765)	1,091,160	(162,145)
Beginning Balance at Dec. 31, 2011	1,565,953	0	127,937	0	479,882	(23,887)	1,131,203	(149,182)
Net income	30,344	0	0	0	0	0	30,344	0
Cash dividends - common stock	17,337						17,337	0
Nonvested (restricted) shares granted	0				(126)	0	0	126
Restricted stock activity	(739)				574	0	0	(1,313)
Deferred compensation trust	0				(8)	0	0	8
Share-based compensation	4,169				4,169	0	0	0
Net unrealized gains on investment securities, net of taxes	1,715	0	0	0	0	1,715	0	0
Ending Balance at Mar. 31, 2012	$ 1,584,105	$ 0	$ 127,937	$ 0	$ 484,491	$ (22,172)	$ 1,144,210	$ (150,361)