Income Taxes - Components of Income Tax Benefit (Provision) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Current income tax expense	$ (1.2)	$ (0.3)	$ (1.5)	$ (1.0)
Deferred income tax expense	(9.4)	(14.9)	(39.0)	(16.1)
Income tax expense	(10.6)	(15.2)	(40.5)	(17.1)
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected income tax expense based on federal statutory rate	(8.4)	(20.0)	(38.3)	(45.9)
State income tax expense, net of federal benefit	(1.1)	(2.6)	(4.9)	(6.2)
Unit-based compensation	0.9	1.4	7.5	(0.6)
Change in valuation allowance	0.0	10.9	0.0	39.0
Other	(2.0)	(4.9)	(4.8)	(3.4)
Income tax expense	$ (10.6)	$ (15.2)	$ (40.5)	$ (17.1)