Business Segment, Geographic and Major Customer Information - Assets by Reportable Segments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 293,302	$ 329,888
Held for sale	0	4,998
Operating Segments
Segment Reporting Information [Line Items]
Assets	293,302	324,890
Operating Segments | Energy Chemistry Technologies
Segment Reporting Information [Line Items]
Assets	145,853	172,799
Operating Segments | Consumer and Industrial Chemistry Technologies
Segment Reporting Information [Line Items]
Assets	132,381	116,600
Corporate and Other
Segment Reporting Information [Line Items]
Assets	$ 15,068	$ 35,491