Derivative Instruments and Hedging Activities (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair value of derivative instruments
Asset Derivative	$ 174,803	$ 50,763
Liability Derivative	126,242	69,199
Designated as hedging instruments | Foreign currency forward contracts | Other current assets
Fair value of derivative instruments
Asset Derivative	68,889	23,536
Liability Derivative	32,430	1,177
Designated as hedging instruments | Foreign currency forward contracts | Other current liabilities
Fair value of derivative instruments
Asset Derivative	129	16,656
Liability Derivative	3,940	21,645
Designated as hedging instruments | Foreign currency forward contracts | Other non-current liabilities
Fair value of derivative instruments
Liability Derivative	24,832	33,824
Not designated as hedging instruments | Foreign currency forward contracts | Other current assets
Fair value of derivative instruments
Asset Derivative	66,639	8,127
Liability Derivative	10,395	1,976
Not designated as hedging instruments | Foreign currency forward contracts | Other current liabilities
Fair value of derivative instruments
Asset Derivative	2,462	2,444
Liability Derivative	22,289	10,577
Not designated as hedging instruments | Foreign currency forward contracts | Other non-current assets
Fair value of derivative instruments
Asset Derivative	36,684
Liability Derivative	$ 32,356