Segment Reporting - Reconciliation of Segment Information to Income Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Operating Income		$ 23,949	$ 19,517	$ 62,785	$ 58,383
Business restructuring expense			(5,628)		(5,827)
Other Income (Expense)
Interest, net		(3,621)	(2,987)	(9,353)	(9,674)
Other, net		989	(690)	4,551	3,348
Income before provision for income taxes		21,317	15,840	57,983	52,057
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating Income		45,278	39,588	121,986	114,411
Operating Segments [Member] | Surfactants [Member]
Segment Reporting Information [Line Items]
Operating Income		26,303	15,373	69,445	57,570
Operating Segments [Member] | Polymers [Member]
Segment Reporting Information [Line Items]
Operating Income		15,248	21,813	37,227	48,137
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Operating Income		3,727	2,402	15,314	8,704
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expenses	[1]	$ (21,329)	$ (14,443)	$ (59,201)	$ (50,201)

[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. Unallocated corporate expenses for the three and nine month periods ended September 30, 2024 also include expenses related to a criminal social engineering scheme that impacted one of the Company's subsidiaries in Asia. The social engineering expenses recognized for the three and nine month periods ended September 30, 2024 were $3,300,000 and $6,800,000, respectively. See Note 17, Other Matter, below for detailed information about the charge.