Restructuring - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Apr. 30, 2017
Restructuring Cost and Reserve [Line Items]
Cash paid		$ 600	$ 1,400
Technical Nonwovens
Restructuring Cost and Reserve [Line Items]
Estimated pre-tax restructuring expense		5,000	5,000
Restructuring, expected costs resulting in future cash expenditures						$ 4,800
Cash paid			1,407	$ 3,500
Pre-tax restructuring expenses, excluding depreciation		400	1,700
Technical Nonwovens | Selling, Product Development and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses, excluding depreciation		500	1,900
Technical Nonwovens | Cost of Sales
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses, excluding depreciation		$ 100	$ 200
Forecast | Technical Nonwovens
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring expenses, excluding depreciation	$ 600				$ 2,500