Derivative Instruments - Balance Sheet Location (Details) (Foreign Exchange Contract [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Other Current Assets [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	$ 928	$ 5,744
Gross amounts offset in the balance sheet	(532)	(3,081)
Net amounts presented in other current assets	396	2,663
Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	3,529	4,289
Gross amounts offset in the balance sheet	(1,757)	(3,281)
Net amounts presented in other current liabilities	1,772	1,008
Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	0	3,019
Gross amounts offset in the balance sheet	0	(1,492)
Net amounts presented in other current assets	0	1,527
Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	1,793	0
Gross amounts offset in the balance sheet	(859)	0
Net amounts presented in other current liabilities	934	0
Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	928	2,725
Gross amounts offset in the balance sheet	(532)	(1,589)
Net amounts presented in other current assets	396	1,136
Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	1,736	4,289
Gross amounts offset in the balance sheet	(898)	(3,281)
Net amounts presented in other current liabilities	$ 838	$ 1,008