Revenue from Contracts with Customers - Disaggregation of Revenue by Product Line (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Revenue from Contracts with Customers [Abstract]
Net sales	$ 2,072.6	$ 2,118.5	$ 2,169.9
Household & Personal Care [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	512.8	530.0	517.6
Specialty Additives [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	584.9	610.2	642.6
High-Temperature Technologies [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	704.7	713.2	720.9
Environmental & Infrastructure [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	270.2	265.1	288.8
Consumer & Specialties [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	1,097.7	1,140.2	1,160.2
Consumer & Specialties [Member] | Household & Personal Care [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	512.8	530.0	517.6
Consumer & Specialties [Member] | Specialty Additives [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	584.9	610.2	642.6
Engineered Solutions [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	974.9	978.3	1,009.7
Engineered Solutions [Member] | High-Temperature Technologies [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	704.7	713.2	720.9
Engineered Solutions [Member] | Environmental & Infrastructure [Member]
Revenue from Contracts with Customers [Abstract]
Net sales	$ 270.2	$ 265.1	$ 288.8