Fair Value Measurements and Derivative Instruments (Derivative Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Total net derivative asset (liabilities)	$ 1,668	$ (1,492)
Total derivative assets
Derivative [Line Items]
Total net derivative asset (liabilities)	2,207	2,225
Total derivative liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(539)	(3,717)
Foreign exchange contracts | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	50	487
Foreign exchange contracts | Derivatives designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(401)	(136)
Foreign exchange contracts | Derivatives not designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	248	150
Foreign exchange contracts | Derivatives not designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(138)	(3,581)
Interest rate swap | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	$ 1,909	$ 1,588