Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Income Tax Contingency [Line Items]
Income tax provision	$ 37,398,000	$ 61,404,000	$ 120,383,000	$ 117,225,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Effective tax rate	30.90%	31.40%	26.80%	21.40%
Federal statutory rate	35.00%	35.00%	35.00%	35.00%
Income tax benefit from change in estimate of unrecognized tax benefits related to share-based compensation				54,100,000
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance		3,200,000		8,400,000
Possible decrease in gross unrecognized tax benefits within next 12 months	5,500,000		5,500,000
Domestic Country [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions			7,500,000
Foreign Country [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Number of Ongoing Tax Examinations	2		2
Interest and penalties recorded	$ 4,600,000		$ 4,600,000