Market Risks and Derivative Hedge Contracts (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Derivatives, Fair Value [Line Items]
Total	$ (99)		$ (99)		$ (362)
Derivative [Line Items]
Net gains associated with foreign currency derivatives	400	$ 500	1,600	$ 200
Forward Purchase Contract, Pounds Sterling [Member]
Derivative [Line Items]
U.S. Dollar notional amount	$ 4,635		$ 4,635
Traded exchange rate	1.31		1.31
Value date	Oct. 19, 2016
Forward Purchase Contract, Mexican Pesos [Member]
Derivative [Line Items]
U.S. Dollar notional amount	$ 6,758		$ 6,758
Traded exchange rate	19.38		19.38
Value date	Oct. 19, 2016
Forward Sale Contract, Mexican Pesos (2) [Member]
Derivative [Line Items]
U.S. Dollar notional amount	$ 2,781		$ 2,781
Traded exchange rate	19.38		19.38
Value date	Oct. 19, 2016
Forward Sale Contract, Norwegian Krone [Member]
Derivative [Line Items]
U.S. Dollar notional amount	$ 1,218		$ 1,218
Traded exchange rate	8.21		8.21
Value date	Oct. 19, 2016
Current Assets [Member]
Derivatives, Fair Value [Line Items]
Forward purchase contracts	$ 0		$ 0		0
Forward sale contracts	6		6		23
Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Forward purchase contracts	(73)		(73)		(354)
Forward sale contracts	$ (32)		$ (32)		$ (31)