Income Taxes - Components of Income Tax Benefit (Provision) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Current income tax expense	$ (0.5)	$ 0.0	$ (0.7)	$ (0.1)
Deferred income tax benefit (expense)	1.8	(6.6)	(1.2)	(7.9)
Total income tax benefit (expense)	1.3	(6.6)	(1.9)	(8.0)
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected income tax benefit (expense) based on federal statutory rate	(17.8)	3.8	(25.9)	6.2
State income tax benefit (expense), net of federal benefit	(2.5)	0.6	(3.6)	0.8
Unit-based compensation	0.0	(0.4)	(2.0)	(2.9)
Change in valuation allowance	21.0	(1.0)	28.1	(2.2)
Oklahoma statutory rate change	0.0	(7.6)	0.0	(7.6)
Other	0.6	(2.0)	1.5	(2.3)
Total income tax benefit (expense)	$ 1.3	(6.6)	$ (1.9)	(8.0)
Deferred state income tax expense (benefit)		$ (7.6)		$ 7.6