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, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Federal tax at statutory rate	$ (0.7)	$ 4.1	$ 10.7
State tax, net of federal tax (benefit) expense	(0.8)	1.2	3.6
Tax effect of:
Equity-based compensation	0.9	0.6	1.2
Non-deductible officers compensation	1.1	0.7	0.0
Provision to return and deferred tax adjustments	(0.8)	(0.3)	(0.6)
Non-deductible promotional and entertainment expense	0.6	0.4	0.6
Fuel tax credit and other credits	(0.7)	(0.8)	(0.8)
Carryback claim, net of adjustments	0.8	(0.3)	(10.1)
Rate change	0.5	0.0	0.0
Valuation Allowance	5.1	0.0	0.0
Other, net	(0.2)	0.0	0.0
Total income tax expense (benefit)	$ 4.6	$ 5.6	$ 4.6