Goodwill - Carrying Value of Goodwill (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill [Roll Forward]
Balance, beginning of period	$ 56,660,000
Goodwill impairment recognized	0	$ 0
Balance, end of period	56,660,000
Energy Chemistry Technologies
Goodwill [Roll Forward]
Balance, beginning of period	37,180,000
Goodwill impairment recognized	0
Balance, end of period	37,180,000
Consumer and Industrial Chemistry Technologies
Goodwill [Roll Forward]
Balance, beginning of period	19,480,000
Goodwill impairment recognized	0
Balance, end of period	$ 19,480,000