Goodwill and Long-Lived Assets - Gross and Net Carrying Amounts of Goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill	$ 209,123	$ 81,129
Accumulated amortization/impairment	(12,160)	(12,160)
Goodwill	196,963	68,969	$ 63,606
Performance Materials
Goodwill [Line Items]
Goodwill	144,626	13,307
Accumulated amortization/impairment	0	0
Goodwill	144,626	13,307	12,777
Technical Nonwovens
Goodwill [Line Items]
Goodwill	52,337	55,662
Accumulated amortization/impairment	0	0
Goodwill	52,337	55,662	$ 50,829
Thermal Acoustical Solutions
Goodwill [Line Items]
Goodwill	12,160	12,160
Accumulated amortization/impairment	(12,160)	(12,160)
Goodwill	$ 0	$ 0