Financial Instruments - Derivatives (Details) In Thousands, unless otherwise specified	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 Cross Currency Interest Rate Contract [Member] Designated as Hedging Instrument [Member] USD ($)	Dec. 31, 2012 Cross Currency Interest Rate Contract [Member] Designated as Hedging Instrument [Member] CHF	Dec. 31, 2012 Cross Currency Interest Rate Contract [Member] Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2011 Cross Currency Interest Rate Contract [Member] Designated as Hedging Instrument [Member] Other Liabilities [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] Prepaid and Other Current Assets [Member] USD ($)	Dec. 31, 2011 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] Prepaid and Other Current Assets [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] Other Accrued Expenses [Member] USD ($)	Dec. 31, 2011 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] Other Accrued Expenses [Member] USD ($)
Derivatives, Fair Value [Line Items]
Notional amount of forward contracts	$ 9,090	$ 83,541
Notional amount of cross currency swap			50,000	65,100
Fair Value - Asset							85	394
Fair Value - Liability					$ (22,681)	$ (21,656)			$ (799)	$ (1,284)