Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accounting Policies [Abstract]
Net foreign exchange transaction gains (loss)	$ (500)	$ (400)	$ (1,638)	$ (424)
Accumulated income (loss) related to currency translation adjustments	(46,800)	(41,000)	(46,800)	(41,000)
Accumulated income (loss) related to derivative transactions	(7,000)	100	(7,000)	100
Accumulated income (loss) related to pension activity	$ 600	$ (500)	$ 600	$ (500)