Restructuring - Actual and Estimated Pre-Tax Expenses (Details) - Technical Nonwovens - USD ($) $ in Thousands	3 Months Ended	12 Months Ended	15 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2019	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Total estimated expenses				$ 4,200
Total pre-tax expense incurred	$ 376	$ 2,959	$ 3,335
Estimated remaining expense	865	1,241	865
Severance and Related Expenses
Restructuring Cost and Reserve [Line Items]
Total estimated expenses				1,250
Total pre-tax expense incurred	16	787	803
Estimated remaining expense	447	463	447
Contract Termination Expenses
Restructuring Cost and Reserve [Line Items]
Total estimated expenses				450
Total pre-tax expense incurred	0	290	290
Estimated remaining expense	160	160	160
Facility Exit, Move and Set-up Expenses
Restructuring Cost and Reserve [Line Items]
Total estimated expenses				$ 2,500
Total pre-tax expense incurred	360	1,882	2,242
Estimated remaining expense	$ 258	$ 618	$ 258