Financial Instruments and Risk Management 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, 2013	Dec. 31, 2012
Not Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 2,956	$ 4,072
Not Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	280	743
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	1,936	2,147
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	24	489
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	872	579
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Long Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 95	$ 0