Segment Information - Operating Income by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Consolidated Operating Income	$ 13,679	$ 10,078
Operating Segments | Performance Materials
Segment Reporting Information [Line Items]
Consolidated Operating Income	2,138	1,306
Operating Segments | Industrial Filtration
Segment Reporting Information [Line Items]
Consolidated Operating Income	3,926	3,154
Operating Segments | Thermal/Acoustical Metals
Segment Reporting Information [Line Items]
Consolidated Operating Income	3,557	3,581
Operating Segments | Thermal/Acoustical Fibers
Segment Reporting Information [Line Items]
Consolidated Operating Income	10,324	7,093
Operating Segments | Other Products and Services
Segment Reporting Information [Line Items]
Consolidated Operating Income	0	118
Corporate Office Expenses
Segment Reporting Information [Line Items]
Consolidated Operating Income	$ (6,266)	$ (5,174)