Segment Information - Assets (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Assets	$ 1,877.7	$ 2,022.6
Operating Segments
Segment Reporting Information [Line Items]
Assets	1,817.6	1,959.6
Operating Segments | Performance Materials
Segment Reporting Information [Line Items]
Assets	853.2	824.3
Operating Segments | Performance Chemicals
Segment Reporting Information [Line Items]
Assets	558.2	567.1
Operating Segments | Advanced Polymer Technologies segment
Segment Reporting Information [Line Items]
Assets	406.2	568.2
Corporate and other
Segment Reporting Information [Line Items]
Assets	$ 60.1	$ 63.0