Segment Reporting - Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net sales	$ 602,688	$ 464,480	$ 1,735,939	$ 1,375,016
Surfactants [Member]
Segment Reporting Information [Line Items]
Net sales	387,734	333,839	1,142,672	993,245
Polymers [Member]
Segment Reporting Information [Line Items]
Net sales	198,841	116,682	539,764	335,582
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales	$ 16,113	$ 13,959	$ 53,503	$ 46,189