Investment in TiO2 Manufacturing Joint Venture and Other Assets - Other Noncurrent Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other assets:
Restricted cash and cash equivalents	$ 32.4	$ 37.2
Note receivables - OPA	69.1	49.3
Operating lease right-of-use assets	$ 22.7	$ 21.5
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total	Total
Restricted Cash and Cash Equivalents, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total	Total
Land held for development	$ 19.4	$ 29.7
IBNR receivables	13.4	16.8
Other	16.7	24.3
Total	$ 173.7	$ 178.8