Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation Of Revenue [Line Items]
Net sales	$ 460,549	$ 473,003	$ 910,536	$ 962,173
Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	332,335	313,380	659,406	663,030
Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	112,409	140,636	218,900	260,815
Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	15,805	18,987	32,230	38,328
North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	289,680	294,221	572,961	595,866
North America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	207,571	191,720	415,517	406,017
North America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	68,780	86,434	130,621	157,757
North America [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	13,329	16,067	26,823	32,092
Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	90,980	101,365	190,131	218,264
Europe [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	55,812	54,360	115,472	125,838
Europe [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	32,692	44,085	69,252	86,190
Europe [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	2,476	2,920	5,407	6,236
Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	56,657	55,407	103,806	106,416
Latin America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	56,194	53,957	102,704	104,769
Latin America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	463	1,450	1,102	1,647
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	23,232	22,010	43,638	41,627
Asia [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	12,758	13,343	25,713	26,406
Asia [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	10,474	8,667	17,925	15,221
Asia [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 0	$ 0	$ 0	$ 0