Hedging Contracts not designated as hedging instruments (Details) - 30-day euro forward contracts - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Cost of Sales [Member]
Derivative [Line Items]
Unrealized gains (losses) on foreign currency derivative instruments not designated as hedges recorded in Net sales		$ 5,351		$ 5,610
Foreign Currency Transaction Gain (Loss), Unrealized	$ (1,009)	$ (8,095)	$ (8,351)	$ (12,041)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Term of Contract			30 days