Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current (benefit) provision:
Federal	$ (38.7)	$ 19.2	$ 10.1
State and local	3.0	6.0	3.8
Foreign	0.1	0.0	0.0
Current (benefit) provision	(35.6)	25.2	13.9
Deferred provision:
Federal	28.7	16.1	35.0
State and local	1.5	15.5	2.5
Foreign	0.1	0.0	(0.1)
Deferred provision	30.3	31.6	37.4
Income tax (benefit) provision	$ (5.3)	$ 56.8	$ 51.3