Leases - Schedule of Supplemental Consolidated Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Operating leases:
Operating lease right-of-use assets	$ 106.1	$ 112.3	$ 112.3
Current operating lease liabilities	21.5	22.0	22.0
Operating lease liabilities	86.4	$ 91.5	91.5
Total operating lease liabilities	$ 107.9		$ 113.5
Weighted average remaining lease term, in years	6 years 9 months 18 days		7 years 1 month 6 days
Weighted average discount rate	7.70%		7.70%