Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Net sales	$ 464,480	$ 451,582	$ 1,375,016	$ 1,413,755
Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	333,839	299,719	993,245	962,749
Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	116,682	135,089	335,582	395,904
Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	13,959	16,774	46,189	55,102
North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	282,816	277,231	855,777	873,097
North America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	202,121	178,799	617,638	584,816
North America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	68,635	84,397	199,256	242,154
North America [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	12,060	14,035	38,883	46,127
Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	96,704	99,781	286,835	318,045
Europe [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	56,468	57,190	171,940	183,028
Europe [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	38,337	39,852	107,589	126,042
Europe [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	1,899	2,739	7,306	8,975
Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	61,116	52,732	164,922	159,148
Latin America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	60,393	51,940	163,097	156,709
Latin America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	723	792	1,825	2,439
Latin America [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	0	0	0	0
Asia [Member]
Disaggregation Of Revenue [Line Items]
Net sales	23,844	21,838	67,482	63,465
Asia [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	14,857	11,790	40,570	38,196
Asia [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	8,987	10,048	26,912	25,269
Asia [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 0	$ 0	$ 0	$ 0