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	89,060	0	0	0	0	0	89,060	0
Cash dividends - common stock	(51,933)						(51,933)	0
Nonvested (restricted) shares granted	0				(13,985)	0	0	13,985
Restricted stock activity	(2,257)				(494)	0	0	(2,751)
Deferred compensation trust	0				42	0	0	(42)
Share-based compensation	6,620				6,620	0	0	0
Net unrealized gains on investment securities, net of taxes	21,449	0	0	0	0	21,449	0	0
Ending Balance at Sep. 30, 2011	1,570,654	0	127,937	0	478,738	(4,654)	1,118,027	(149,394)
Beginning Balance at Dec. 31, 2011	1,565,953	0	127,937	0	479,882	(23,887)	1,131,203	(149,182)
Net income	95,882	0	0	0	0	0	95,882	0
Cash dividends - common stock	(52,084)						(52,084)	0
Nonvested (restricted) shares granted	0				(14,481)	0	0	14,481
Restricted stock activity	(2,341)				(1,023)	0	0	(3,364)
Deferred compensation trust	0				50	0	0	(50)
Share-based compensation	7,258				7,258	0	0	0
Net unrealized gains on investment securities, net of taxes	9,987	0	0	0	0	9,987	0	0
Other capital surplus	49				49
Ending Balance at Sep. 30, 2012	$ 1,624,704	$ 0	$ 127,937	$ 0	$ 473,781	$ (13,900)	$ 1,175,001	$ (138,115)