Derivative Instruments (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Currency swaps | Derivatives not designated as hedging instruments
Derivative Instruments
Notional amounts of derivatives		$ 86,400,000
Liability Derivatives
Liability Derivatives, Accounts payable		1,368,000
Forward exchange contracts | Derivatives not designated as hedging instruments
Derivative Instruments
Notional amounts of derivatives	16,500,000	12,000,000
Asset Derivatives
Asset Derivatives, Accounts receivable	74,000	90,000
Liability Derivatives
Liability Derivatives, Accounts payable	72,000	77,000
Derivatives not designated as hedging instruments
Asset Derivatives
Asset Derivatives, Accounts receivable	74,000	90,000
Liability Derivatives
Liability Derivatives, Accounts payable	$ 72,000	$ 1,445,000
Forward exchange contracts
Derivative Instruments
Derivative maturity period, less than	6 months