Unaudited Condensed Consolidated Statements Of Shareholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
Balance, at beginning of period at Dec. 31, 2010	$ 3,075,820	$ 600,055	$ 170,239	$ (112,811)	$ 57,135	$ 2,361,202
Net income	91,448					91,448
Dividends	(28,600)	(28,600)
Other comprehensive loss	(39,339)				(39,339)
Stock compensation	17,365		(42,822)	60,187
Share repurchases	(60,000)			(60,000)
Repurchase of founder warrants	(53,620)		(53,620)
Balance, at end of period at Sep. 30, 2011	3,003,074	571,455	73,797	(112,624)	17,796	2,452,650
Balance, at beginning of period at Dec. 31, 2011	3,149,022	557,153	78,225	(136,590)	14,484	2,635,750
Net income	534,154					534,154
Dividends - par value reduction	(40,419)	(40,419)
Other comprehensive loss	(13,099)				(13,099)
Stock compensation	13,176		(23,050)	36,226
Share repurchases	(207,048)			(207,048)
Shares cancelled	0	(39,488)	(55,175)	186,468		(91,805)
Balance, at end of period at Sep. 30, 2012	$ 3,435,786	$ 477,246	$ 0	$ (120,944)	$ 1,385	$ 3,078,099