Segment Reporting - Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Net Sales	$ 454,603	$ 452,414	$ 900,500	$ 912,865
Surfactants [Member]
Segment Reporting Information [Line Items]
Net Sales	298,587	299,743	608,547	630,294
Polymers [Member]
Segment Reporting Information [Line Items]
Net Sales	134,498	133,613	248,396	242,977
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net Sales	$ 21,518	$ 19,058	$ 43,557	$ 39,594