Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Federal
Current	$ 0.1
Deferred taxes and other accruals	12.5	$ 6.2	$ (0.1)
State	2.0	1.1
Total provision (benefit) for income taxes	$ 14.6	$ 7.3	$ (0.1)