Leases - Schedule of Maturities of Lease Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Finance Lease Liabilities, Payments, Due [Abstract]
2021	$ 1.4
2022	1.1
2023	0.7
2024	0.4
2025	0.1
Total lease payments	3.7
Less: imputed interest	(0.4)
Total future lease obligation	3.3	$ 4.2
Operating Lease Liabilities, Payments Due [Abstract]
2021	10.8
2022	8.5
2023	7.0
2024	4.3
2025	3.2
Thereafter	5.9
Total lease payments	39.7
Less: imputed interest	(5.7)
Total future lease obligation	$ 34.0	$ 41.3	$ 38.0