Fair Value Measurements and Derivative Instruments (Derivative Instruments) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Total net derivative asset	$ 1,296,000	$ 1,563,000
Total derivative assets
Derivative [Line Items]
Derivative asset	2,031,000	1,898,000
Total derivative liabilities
Derivative [Line Items]
Derivative liability	(735,000)	(335,000)
Foreign exchange contracts | Derivatives designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Derivative asset	61,000	57,000
Foreign exchange contracts | Derivatives designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Derivative liability	(104,000)	(144,000)
Foreign exchange contracts | Derivatives not designated as hedging instruments | Other current assets and prepayments
Derivative [Line Items]
Derivative asset	1,970,000	65,000
Foreign exchange contracts | Derivatives not designated as hedging instruments | Accounts payable and accrued liabilities
Derivative [Line Items]
Derivative liability	(631,000)	(191,000)
Interest rate swap | Derivatives designated as hedging instruments | Other non-current assets
Derivative [Line Items]
Derivative asset	0	1,776,000
Cash Flow Hedging
Derivative [Line Items]
Total notional amount of outstanding contracts	8,000,000	$ 10,000,000
Cash Flow Hedging | Interest rate contract
Derivative [Line Items]
Total notional amount of outstanding contracts	$ 300,000,000