Derivative Instruments and Hedging Activities Disclosure (Details Textual) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Derivative Instruments and Hedging Activities Disclosure (Textuals) [Abstract]
Notional amount of the foreign currency derivative instruments	$ 244,115	$ 234,600
Maturities of forward contracts	Less then twelve months
Effective portion of change in fair value of foreign currency forward contracts	(6,284)	(3,263)
Fair value of assets held for sale	$ 8,155