Other Noncurrent Liabilities - Other Noncurrent Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Operating lease liabilities	$ 20.3	$ 22.2
Reserve for uncertain tax positions	14.7	13.6
Accrued litigation settlement	60.4	60.1
Deferred income	46.1	47.4
Other postretirement benefits	9.7	10.5
Employee benefits	5.8	6.0
Insurance claims and expenses	10.1	11.0
Deferred payment obligation	9.9	9.9
Accrued development costs	8.0	8.3
Other	8.5	8.2
Total	$ 193.5	$ 197.2