Other Noncurrent Liabilities - Other Noncurrent Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Accrued development costs	$ 38.0	$ 48.1
Operating lease liabilities	$ 16.9	$ 17.4
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total	Total
Accrued litigation settlement	$ 16.0	$ 27.4
Insurance claims and expenses	15.1	18.7
Deferred income	13.8	25.9
Other postretirement benefits	7.2	7.1
Employee benefits	4.7	4.8
Reserve for uncertain tax positions	0.4	0.3
Other	7.2	6.7
Total	$ 119.3	$ 156.4