Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Income Tax Contingency [Line Items]
Income tax provision	$ 7,008,000	$ 41,271,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Effective tax rate	30.10%	24.10%
Federal statutory rate	35.00%	35.00%
Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations	3,400,000
Possible decrease in gross unrecognized tax benefits within next 12 months	2,700,000
Domestic Country [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	2,900,000
Foreign Country [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Number of Ongoing Tax Examinations	2
Interest and penalties recorded	$ 4,600,000