Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 28,585	$ 28,775
Accumulated impairment loss, Beginning Balance	(3,467)	(3,467)
Goodwill net, Beginning Balance	25,118	25,308
Goodwill measurement period adjustment		(120)
Foreign currency translation	(2,164)	(70)
Goodwill, Ending Balance	26,421	28,585
Accumulated impairment loss, Ending Balance	(3,467)	(3,467)
Goodwill net, Ending Balance	22,954	25,118
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	22,627	22,958
Accumulated impairment loss, Beginning Balance	(3,467)	(3,467)
Goodwill net, Beginning Balance	19,160	19,491
Goodwill measurement period adjustment		(120)
Foreign currency translation	(2,106)	(211)
Goodwill, Ending Balance	20,521	22,627
Accumulated impairment loss, Ending Balance	(3,467)	(3,467)
Goodwill net, Ending Balance	17,054	19,160
Polymer Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	5,475	5,334
Goodwill net, Beginning Balance	5,475	5,334
Foreign currency translation	(58)	141
Goodwill, Ending Balance	5,417	5,475
Goodwill net, Ending Balance	5,417	5,475
Specialty Products Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	483	483
Goodwill net, Beginning Balance	483	483
Goodwill, Ending Balance	483	483
Goodwill net, Ending Balance	$ 483	$ 483