Segment Information (Classification of Segments) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Operating Income	$ 52,477	$ 34,048	$ 28,713
Total Assets	358,260	361,770	274,685
Capital Expenditures	21,555	19,001	13,826
Depreciation and Amortization	17,275	17,646	12,703
Operating Segments | Performance Materials Segment
Segment Reporting Information [Line Items]
Operating Income	6,790	9,706	9,462
Total Assets	66,706	71,325	74,838
Capital Expenditures	3,519	4,124	4,604
Depreciation and Amortization	4,499	4,654	4,667
Operating Segments | Industrial Filtration Segment
Segment Reporting Information [Line Items]
Operating Income	13,431	6,412	0
Total Assets	89,566	100,201	0
Capital Expenditures	968	1,804	0
Depreciation and Amortization	4,996	4,536	0
Operating Segments | Thermal/Acoustical Metals Segment
Segment Reporting Information [Line Items]
Operating Income	15,517	13,823	14,088
Total Assets	111,195	106,210	104,908
Capital Expenditures	11,494	8,544	6,027
Depreciation and Amortization	4,233	4,578	4,777
Operating Segments | Thermal/Acoustical Fibers Segment
Segment Reporting Information [Line Items]
Operating Income	37,086	29,167	21,486
Total Assets	38,881	33,109	30,176
Capital Expenditures	4,807	3,296	1,887
Depreciation and Amortization	2,400	2,166	2,217
Operating Segments | Other Products and Services
Segment Reporting Information [Line Items]
Total Assets	0	11,580	11,866
Capital Expenditures	22	574	243
Depreciation and Amortization	45	804	588
Operating Segments | Other Products and Services | Life Sciences Vital Fluids
Segment Reporting Information [Line Items]
Operating Income	118	1,582	778
Corporate
Segment Reporting Information [Line Items]
Operating Income	(20,465)	(26,642)	(17,101)
Total Assets	51,912	39,345	52,897
Capital Expenditures	745	659	1,065
Depreciation and Amortization	$ 1,102	$ 908	$ 454