Financial Instruments and Risk Management (Balance Sheet Classification and Fair Value of Derivative Instruments) (Details) (Forward Contracts [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Not Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 4,072	$ 645
Not Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	743	2,962
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	2,147	6,591
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	489	1,117
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	579	824
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Long Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 0	$ 91