Foreign Currency Derivative Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of foreign currency gains and losses on underlying assets and liabilities
Net gains (loss) on foreign currency forward contracts were partially offset on assets and liabilities	$ 1,238	$ (984)
Cost of Sales [Member]
Schedule of foreign currency gains and losses on underlying assets and liabilities
Net gains (loss) on foreign currency forward contracts were partially offset on assets and liabilities	(8)	13
Selling, General and Administrative Expenses [Member]
Schedule of foreign currency gains and losses on underlying assets and liabilities
Net gains (loss) on foreign currency forward contracts were partially offset on assets and liabilities	$ 1,246	$ (997)