Derivative Financial Instruments (Details 2) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Derivative liability	$ 12,196	$ 16,751
Cross-currency swap [Member] | Not Designated as Hedging Instrument [Member] | Accrued expenses [Member]
Derivative liability	4,068	5,541
Cross-currency swap [Member] | Not Designated as Hedging Instrument [Member] | Other long-term liabilities [Member]
Derivative liability	0	2,091
Not Designated as Hedging Instrument [Member]
Derivative liability	4,068	7,632
Designated as Hedging Instrument [Member]
Derivative liability	8,128	9,119
Designated as Hedging Instrument [Member] | Accrued expenses [Member] | Interest rate swap [Member]
Derivative liability	4,185	4,202
Designated as Hedging Instrument [Member] | Other long-term liabilities [Member] | Interest rate swap [Member]
Derivative liability	$ 3,943	$ 4,917