Income Taxes - Schedule of Income Tax Expense (Benefit) Differs from Amount Computed at Federal Statutory Corporate Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Federal tax at statutory rate	$ 4.1	$ 10.7	$ (10.8)
State tax, net of federal tax (benefit) expense	1.2	3.6	(2.5)
Tax effect of:
Equity-based compensation	0.6	1.2	1.5
Non-deductible officers compensation	0.7	0.0	0.0
Provision to return and deferred tax adjustments	(0.3)	(0.6)	(0.7)
Non-deductible promotional and entertainment expense	0.4	0.6	0.6
Goodwill impairment	0.0	0.0	3.3
Fuel tax credit and other credits	(0.8)	(0.8)	(0.8)
Change in uncertain tax positions	0.0	0.0	(0.1)
Carryback claim, net of adjustments	(0.3)	(10.1)	0.0
Other, net	0.0	0.0	(0.1)
Total income tax expense (benefit)	$ 5.6	$ 4.6	$ (9.6)