Consolidated Statements of Shareholders' Equity and Comprehensive Income (loss) (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning Balance at Dec. 31, 2009	$ 1,936,482	$ 370,290	$ 482,491	$ 1,257,730	$ 71,999	$ 7,458	$ (253,486)
Beginning Balance (in shares) at Dec. 31, 2009			176,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	128,332				128,332
Other comprehensive income	5,037					5,037
Stock issued, including related tax benefits	231,510		56,001	171,201			4,308
Stock issued, including related tax benefits (in shares)			22,686
Stock-based compensation awards	1,996			1,996
Redemption Of Preferred Stock And repurchase of common stock warrant	(387,300)	(376,500)		(10,800)
Preferred stock discount accretion	0	6,210			(6,210)
Preferred stock cash dividends	(12,496)				(12,496)
Treasury Stock, Value, Acquired, Cost Method	0
Common stock cash dividends	(23,172)				(23,172)
Ending Balance at Dec. 31, 2010	1,880,389	0	538,492	1,420,127	158,453	12,495	(249,178)
Ending Balance (in shares) at Dec. 31, 2010			199,050
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	145,573				145,573
Other comprehensive income	(4,540)					(4,540)
Stock issued, including related tax benefits	6,835		1,894	(649)			5,590
Stock issued, including related tax benefits (in shares)			1,114
Stock-based compensation awards	4,249			4,249
Treasury Stock, Value, Acquired, Cost Method	0
Common stock cash dividends	(39,967)				(39,967)
Ending Balance at Dec. 31, 2011	1,992,539	0	540,386	1,423,727	264,059	7,955	(243,588)
Ending Balance (in shares) at Dec. 31, 2011			200,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	159,845				159,845
Other comprehensive income	(2,280)					(2,280)
Stock issued, including related tax benefits	7,044		1,707	(2,294)			7,631
Stock issued, including related tax benefits (in shares)			1,176
Stock-based compensation awards	4,834			4,834
Treasury Stock, Shares, Acquired	2,100						(2,115)
Treasury Stock, Value, Acquired, Cost Method	(20,359)			0			(20,359)
Common stock cash dividends	59,967				59,967
Ending Balance at Dec. 31, 2012	$ 2,081,656	$ 0	$ 542,093	$ 1,426,267	$ 363,937	$ 5,675	$ (256,316)
Ending Balance (in shares) at Dec. 31, 2012			199,225