Foreign Currency Exchange Contracts and Hedging (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Foreign currency exchange contracts	Dec. 31, 2011 Foreign currency exchange contracts	Mar. 31, 2012 Derivatives designated as cash flow hedges Foreign currency exchange contracts	Mar. 31, 2011 Derivatives designated as cash flow hedges Foreign currency exchange contracts	Mar. 31, 2011 Non-designated derivatives Foreign currency exchange contracts
Foreign currency exchange contracts and hedging
Remaining maturity of outstanding foreign currency forward contracts, maximum (in months)		9 months
Notional amounts of foreign currency hedging contracts		$ 60,000	$ 66,000
Reclassification period of total accumulated other comprehensive income expected to be transferred into income, maximum (in months)	12 months
Summary of the effect of derivative instruments on the consolidated statements of income
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)				(1,908)	(2,716)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)				106	259
Gain (Loss) from Amount Excluded from Effectiveness Testing				45	78
Amount of Gain (Loss) Recognized in Income on Derivatives						$ (431)