Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 97,356,000	$ 103,430,000
Accumulated impairment loss, Beginning Balance	(5,988,000)	(5,988,000)
Goodwill net, Beginning Balance	91,368,000	97,442,000
Goodwill impairment	(6,245,000)
Foreign currency translation	7,447,000	(6,074,000)
Goodwill, Ending Balance	104,803,000	97,356,000	$ 103,430,000
Accumulated impairment loss, Ending Balance	(12,233,000)	(5,988,000)	(5,988,000)
Goodwill net, Ending Balance	$ 92,570,000	91,368,000	97,442,000
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]	Goodwill and Other Intangibles Impairment Loss Before Tax
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 26,476,000	29,781,000
Accumulated impairment loss, Beginning Balance	(5,505,000)	(5,505,000)
Goodwill net, Beginning Balance	20,971,000	24,276,000
Goodwill impairment	(6,245,000)
Foreign currency translation	1,756,000	(3,305,000)
Goodwill, Ending Balance	28,232,000	26,476,000	29,781,000
Accumulated impairment loss, Ending Balance	(11,750,000)	(5,505,000)	(5,505,000)
Goodwill net, Ending Balance	16,482,000	20,971,000	24,276,000
Polymer Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	70,397,000	73,166,000
Goodwill net, Beginning Balance	70,397,000	73,166,000
Foreign currency translation	5,691,000	(2,769,000)
Goodwill, Ending Balance	76,088,000	70,397,000	73,166,000
Goodwill net, Ending Balance	76,088,000	70,397,000	73,166,000
Specialty Products Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	483,000	483,000
Accumulated impairment loss, Beginning Balance	(483,000)	(483,000)
Goodwill net, Beginning Balance	0	0
Goodwill impairment			(483,000)
Goodwill, Ending Balance	483,000	483,000	483,000
Accumulated impairment loss, Ending Balance	$ (483,000)	(483,000)	(483,000)
Goodwill net, Ending Balance		$ 0	$ 0