Goodwill and Intangible Assets - Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Total Goodwill	$ 164,369	$ 150,816
Total intangibles	133,664	123,587
Accumulated amortization	(51,829)	(39,852)
Net intangibles	81,835	83,735
Composite Fibers [Member]
Finite-Lived Intangible Assets [Line Items]
Total Goodwill	84,586	77,775
Composite Fibers [Member] | Technology and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	41,578	38,256
Composite Fibers [Member] | Tradename - Non Amortizing [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	3,902	4,470
Composite Fibers [Member] | Customer Relationships and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	37,535	34,445
Airlaid Materials [Member]
Finite-Lived Intangible Assets [Line Items]
Total Goodwill	79,783	73,041
Airlaid Materials [Member] | Tradename [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	3,960	3,625
Airlaid Materials [Member] | Technology and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	20,053	18,406
Airlaid Materials [Member] | Customer Relationships and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	$ 26,636	$ 24,385