Derivative Financial Instruments (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments, Gain (Loss) [Line Items]
Other income/(expense), net	$ 712	$ (827)	$ 2,115
Derivative instruments not designated as hedges	(5,689)	(2,140)
Cross-currency swap agreement [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest (expense)/income	(5,935)	(449)
Other income/(expense), net	246	(975)
Foreign currency forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other income/(expense), net	$ 0	$ (716)