Basis of Presentation (Details) (USD $)	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010		Sep. 30, 2010 As Reported [Member]	Sep. 30, 2010 Correction [Member]	Dec. 31, 2008 Correction [Member]	Dec. 31, 2007 Correction [Member]
Assets
Current deferred income taxes	$ 47,833,000	$ 53,794,000	$ 64,768,000	[1]	$ 66,718,000	$ (1,950,000)
Prepaid expenses	27,074,000	19,374,000	34,279,000	[1]	42,729,000	(8,450,000)
Total current assets	1,002,066,000	772,106,000	921,744,000	[1]	932,144,000	(10,400,000)
Goodwill	3,086,716,000	3,097,016,000	3,096,300,000	[1]	3,093,979,000	2,321,000	2,321,000
Total assets	8,381,881,000	8,337,891,000	8,521,518,000	[1]	8,529,597,000	(8,079,000)
Liabilities
Noncurrent deferred income taxes	800,770,000	849,448,000	856,631,000	[1]	849,925,000	6,706,000		14,785,000
Total liabilities	4,505,782,000	4,372,911,000	4,497,449,000	[1]	4,490,743,000	6,706,000
Equity
Retained earnings	1,372,822,000	1,512,863,000	1,591,969,000	[1]	1,606,754,000	(14,785,000)		14,785,000
Total equity			4,024,069,000		4,038,854,000	(14,785,000)
Total liabilities and equity	$ 8,381,881,000	$ 8,337,891,000	$ 8,521,518,000	[1]	$ 8,529,597,000	$ (8,079,000)

[1] As Restated, See Note 1