Fair Value Measurements and Derivative Instruments (Derivative Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Total net derivative asset (liabilities)	$ 1,353	$ (1,492)
Total derivative assets
Derivative [Line Items]
Total net derivative asset (liabilities)	1,742	2,225
Total derivative liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(389)	(3,717)
Foreign exchange contracts | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	3	487
Foreign exchange contracts | Derivatives designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(309)	(136)
Foreign exchange contracts | Derivatives not designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	59	150
Foreign exchange contracts | Derivatives not designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Total net derivative asset (liabilities)	(80)	(3,581)
Interest rate swap | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Total net derivative asset (liabilities)	$ 1,680	$ 1,588