Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Accrued interest	$ 13.9	$ 18.0
Accrued capital expenditures	10.5	13.6
Other accruals	15.8	22.5
Total	$ 40.2	$ 54.1