Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Reconciliation of liability for unrecognized tax benefits
Balance at the beginning of the period			$ 20,393,000
Additions based on current year positions			2,194,000
Additions based on prior year positions			1,916,000
Currency translation adjustments			(1,459,000)
Balance at the end of the period	23,044,000		23,044,000
Effective income tax rate (as a percent)	146.20%	41.00%	60.50%	39.10%
Prepaid income taxes	$ 30,000,000		$ 30,000,000		$ 68,400,000