Segment Information - Results of Operations (Details) $ in Thousands	3 Months Ended									12 Months Ended
	Mar. 31, 2017 segment	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Information
Number of reportable segments | segment										4
Net Sales		$ 137,480	$ 123,970	$ 132,597	$ 120,199	$ 130,873	$ 132,976	$ 135,452	$ 135,703	$ 514,246	$ 535,004	$ 555,103
Income (loss) from operations										24,522	64,794	74,605
Restructuring income												252
Interest income										99	58	77
Interest expense										(2,385)	(773)	(263)
Other expense - net										(2,163)	(693)	(1,911)
Income before income tax provision										20,073	63,386	72,508
Depreciation and amortization										38,070	35,453	30,470
Activated Carbon and Service
Segment Information
Net Sales										454,565	486,548	498,212
Depreciation and amortization										34,445	32,443	26,820
Equipment
Segment Information
Net Sales										38,864	39,293	45,319
Depreciation and amortization										1,631	2,400	3,049
Consumer
Segment Information
Net Sales										8,695	9,163	11,572
Depreciation and amortization										559	610	601
Other
Segment Information
Net Sales										12,122
Depreciation and amortization										1,435
Expected
Segment Information
Number of reportable segments | segment	3
Business operating segments
Segment Information
Income (loss) from operations										24,522	64,794	74,353
Business operating segments | Activated Carbon and Service
Segment Information
Income (loss) from operations										36,893	67,583	78,114
Business operating segments | Equipment
Segment Information
Income (loss) from operations										(4,633)	(4,210)	(5,657)
Business operating segments | Consumer
Segment Information
Income (loss) from operations										1,051	$ 1,421	$ 1,896
Business operating segments | Other
Segment Information
Income (loss) from operations										$ (8,789)