Business Segment, Geographic and Major Customer Information - Assets by Reportable Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 338,822	$ 329,888
Operating Segments | Energy Chemistry Technologies
Segment Reporting Information [Line Items]
Assets	169,170	177,797
Operating Segments | Consumer and Industrial Chemistry Technologies
Segment Reporting Information [Line Items]
Assets	130,702	116,600
Corporate and Other
Segment Reporting Information [Line Items]
Assets	$ 38,950	$ 35,491