Fair Value Measurements and Derivative Instruments (Derivative Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Total net derivative asset (liabilities)	$ 304	$ (3,671)
Total derivative assets
Derivative [Line Items]
Total net derivative asset (liabilities)	3,237	1,716
Total derivative liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(2,933)	(5,387)
Foreign exchange contracts | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	397	217
Foreign exchange contracts | Derivatives designated as hedging instruments | Accounts payable and accrued liabilities:
Derivative [Line Items]
Total net derivative asset (liabilities)	(706)	(208)
Foreign exchange contracts | Derivatives not designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	2,840	1,499
Foreign exchange contracts | Derivatives not designated as hedging instruments | Accounts payable and accrued liabilities:
Derivative [Line Items]
Total net derivative asset (liabilities)	$ (2,227)	$ (5,179)