Segment Reporting - Reconciliation of Segment Information to Income Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Operating Income		$ 77,640	$ 56,657	$ 140,986	$ 110,571
Business restructuring		(81)	(114)	(133)	(195)
Other Income (Expense)
Interest, net		(2,727)	(1,567)	(5,033)	(3,091)
Other, net		(5,369)	2,758	(7,019)	3,504
Income before provision for income taxes		69,544	57,848	128,934	110,984
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating Income		92,027	75,898	163,620	149,692
Operating Segments [Member] | Surfactants [Member]
Segment Reporting Information [Line Items]
Operating Income		48,249	45,896	102,018	99,106
Operating Segments [Member] | Polymers [Member]
Segment Reporting Information [Line Items]
Operating Income		33,912	23,025	48,041	40,976
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Operating Income		9,866	6,977	13,561	9,610
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expenses	[1]	$ (14,306)	$ (19,127)	$ (22,501)	$ (38,926)

[1]   (1) Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information systems, deferred compensation and environmental remediation) that are not included in segment operating income and are not used to evaluate segment performance.