Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Federal
Current	$ 0.2	$ 0.1	$ 0.1
Deferred taxes and other accruals	59.1	31.2	22.8
State	12.5	6.6	3.7
Total provision (benefit) for income taxes	$ 71.8	$ 37.9	$ 26.6