Restructuring - Accrued Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Cash paid	$ (600)	$ (1,400)
Technical Nonwovens
Restructuring Reserve [Roll Forward]
Balance		333
Pre-tax restructuring expenses, excluding depreciation		1,768
Cash paid		(1,407)	$ (3,500)
Balance	$ 694	$ 694	$ 333