Derivative Instrument (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Derivatives Designated as Cash Flow Hedges [Member]
Derivative Instruments (Textual) [Abstract]
Open forward foreign currency exchange contract designated as a cash flow hedge	$ 3,229,000	$ 3,694,000
Derivatives Designated as Cash Flow Hedges [Member] | Foreign Exchange Contracts [Member]
Derivative Instruments (Textual) [Abstract]
Forward foreign currency exchange	1,508,000	5,266,000
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Contracts [Member]
Derivative Instruments (Textual) [Abstract]
Open forward foreign currency exchange contract not designated as a hedge	$ 15,458,000	$ 26,627,000