Income Taxes - Components of Income Tax Benefit (Provision) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Current income tax expense	$ (0.2)	$ (0.5)	$ (0.3)	$ (0.7)
Deferred income tax benefit (expense)	(18.8)	1.8	(29.6)	(1.2)
Income tax benefit (expense)	(19.0)	1.3	(29.9)	(1.9)
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected income tax expense based on federal statutory rate	(15.4)	(17.8)	(29.9)	(25.9)
State income tax expense, net of federal benefit	(2.0)	(2.5)	(3.8)	(3.6)
Unit-based compensation	0.1	0.0	6.6	(2.0)
Change in valuation allowance	0.0	21.0	0.0	28.1
Other	(1.7)	0.6	(2.8)	1.5
Income tax benefit (expense)	$ (19.0)	$ 1.3	$ (29.9)	$ (1.9)