Goodwill and Intangible Assets - Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Goodwill – Composite Fibers	$ 82,744	$ 73,094
Total intangibles	92,808	82,549
Accumulated amortization	(33,949)	(26,290)
Net intangibles	58,859	56,259
Specialty Papers [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	6,155	6,155
Composite Fibers [Member] | Tradename [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	4,773	4,195
Composite Fibers [Member] | Technology and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	40,686	35,874
Composite Fibers [Member] | Customer Relationships and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	36,705	32,310
Advanced Airlaid Materials [Member] | Technology and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	1,488	1,377
Advanced Airlaid Materials [Member] | Customer Relationships and Related [Member]
Finite-Lived Intangible Assets [Line Items]
Total intangibles	$ 3,001	$ 2,638