Income Taxes - Schedule of Components of Income Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current provision
U.S. federal	$ (15.3)	$ 9.6	$ 9.9
Foreign	0.2	0.9	1.0
State	0.1	4.7	7.4
Total current	(15.0)	15.2	18.3
Deferred provision
U.S. federal	(40.7)	2.9	1.3
Foreign		(0.1)	(0.3)
State	(11.8)	1.4	0.3
Total deferred	(52.5)	4.2	1.3
Income tax (benefit) expense	$ (67.5)	$ 19.4	$ 19.6