Costs Associated with Exit and Restructuring Activities - Restructuring Reserve Activity (Details) - June 2013 Plan, April 2014 Plan and June 2016 Plan $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Restructuring reserve activity
Restructuring liability at beginning	$ 1,913
Restructuring and restructuring-related charges	3,364
Cost paid	(3,780)
Restructuring liability at ending	1,484
Restructuring Reserve, Translation and Other Adjustment	$ (13)