Derivative Instruments and Hedging Activities (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair value of derivative instruments
Asset Derivative	$ 168,321	$ 174,803
Liability Derivative	84,740	126,242
Designated as hedging instruments | Foreign currency forward contracts | Other current assets
Fair value of derivative instruments
Asset Derivative	62,613	68,889
Liability Derivative	19,759	32,430
Designated as hedging instruments | Foreign currency forward contracts | Other current liabilities
Fair value of derivative instruments
Asset Derivative		129
Liability Derivative		3,940
Designated as hedging instruments | Foreign currency forward contracts | Other non-current assets
Fair value of derivative instruments
Asset Derivative	9,375
Liability Derivative	788
Designated as hedging instruments | Foreign currency forward contracts | Other non-current liabilities
Fair value of derivative instruments
Asset Derivative	13
Liability Derivative	2,473	24,832
Designated as hedging instruments | Treasury rate locks | Other current assets
Fair value of derivative instruments
Asset Derivative	1,816
Not designated as hedging instruments | Foreign currency forward contracts | Other current assets
Fair value of derivative instruments
Asset Derivative	67,607	66,639
Liability Derivative	27,358	10,395
Not designated as hedging instruments | Foreign currency forward contracts | Other current liabilities
Fair value of derivative instruments
Asset Derivative	1,093	2,462
Liability Derivative	10,711	22,289
Not designated as hedging instruments | Foreign currency forward contracts | Other non-current assets
Fair value of derivative instruments
Asset Derivative	25,804	36,684
Liability Derivative	$ 23,651	$ 32,356