Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill and Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 15,193	$ 10,666
Accumulated impairment loss, Beginning Balance	(3,467)	(3,467)
Goodwill net, Beginning Balance	11,726	7,199
Goodwill acquired		4,642
Foreign currency translation	(224)	(115)
Goodwill, Ending Balance	14,969	15,193
Accumulated impairment loss, Ending Balance	(3,467)	(3,467)
Goodwill net, Ending Balance	11,502	11,726
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	9,107	9,246
Accumulated impairment loss, Beginning Balance	(3,467)	(3,467)
Goodwill net, Beginning Balance	5,640	5,779
Foreign currency translation	(82)	(139)
Goodwill, Ending Balance	9,025	9,107
Accumulated impairment loss, Ending Balance	(3,467)	(3,467)
Goodwill net, Ending Balance	5,558	5,640
Polymer Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	5,603	937
Goodwill net, Beginning Balance	5,603	937
Goodwill acquired		4,642
Foreign currency translation	(142)	24
Goodwill, Ending Balance	5,461	5,603
Goodwill net, Ending Balance	5,461	5,603
Specialty Products Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance			483
Goodwill net, Beginning Balance			483
Goodwill, Ending Balance	483	483	483
Goodwill net, Ending Balance	$ 483	$ 483	$ 483