Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Net foreign exchange transaction gains (loss)	$ 300	$ 100	$ (1,351)	$ (284)
Accumulated income (loss) related to currency translation adjustments	(43,200)	(44,500)	(43,200)	(44,500)
Accumulated income (loss) related to derivative transactions	(5,500)	(500)	(5,500)	(500)
Accumulated income (loss) related to pension activity	$ 500	$ 500	$ 500	$ 500