Hedging - Derivatives Not Designated as Hedging Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative [Line Items]
(Gains) losses on 30 day euro forward contracts		$ 3,409
30-day euro forward contracts, settlement period - October 2013 | Cost of sales
Derivative [Line Items]
(Gains) losses on 30 day euro forward contracts	(212)	1,942
Gains (losses) from fluctuations in the value of the net monetary assets exposed to euro exchange rates	$ (2,351)	$ (4,222)
Derivatives not designated as hedging instruments | 30-day euro forward contracts, settlement period - October 2013
Derivative [Line Items]
Term of contract	30 days