Segment Reporting - Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Net Sales	$ 468,269	$ 445,897
Surfactants [Member]
Segment Reporting Information [Line Items]
Net Sales	322,603	309,960
Polymers [Member]
Segment Reporting Information [Line Items]
Net Sales	126,610	113,898
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net Sales	$ 19,056	$ 22,039