Segment Information - Results of Operations (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2017 segment	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)
Segment Information
Number of reportable segments | segment	3			3
Net Sales		$ 162,561	$ 123,970	$ 458,262	$ 376,766
Income (loss) from operations		9,676	9,293	26,595	29,927
Interest income		7		39	35
Interest expense		(2,099)	(538)	(5,634)	(1,099)
Other expense — net		(579)	(758)	(74)	(555)
Income before income tax provision		7,005	7,997	20,926	28,308
Depreciation and amortization		11,462	9,082	35,250	27,318
Activated Carbon
Segment Information
Net Sales		141,140	117,535	403,048	351,033
Depreciation and amortization		9,893	8,600	30,461	25,836
Alternative Materials
Segment Information
Net Sales		16,928	1,682	42,706	6,811
Depreciation and amortization		1,335	139	3,960	442
Advanced Water Purification
Segment Information
Net Sales		4,493	4,753	12,508	18,922
Depreciation and amortization		234	343	829	1,040
Business operating segments
Segment Information
Income (loss) from operations		12,984	9,293	29,903	29,927
Business operating segments | Activated Carbon
Segment Information
Income (loss) from operations		12,992	10,717	33,022	31,937
Business operating segments | Alternative Materials
Segment Information
Income (loss) from operations		739	167	502	989
Business operating segments | Advanced Water Purification
Segment Information
Income (loss) from operations		(747)	$ (1,591)	(3,621)	$ (2,999)
Reconciling items: Unallocated
Segment Information
Merger related expenses		$ (3,308)		$ (3,308)