Income Taxes - Components of Net Deferred Tax Asset and Liability Accounts (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Deferred tax assets:
Self-insurance reserves	$ 37.3	$ 31.8
Deferred compensation	2.2	2.8
Payroll related accruals	25.3	22.8
Allowance for doubtful accounts	2.5	1.3
Lease liabilities	22.3	23.6
Net operating loss carryforward	4.9	7.1
Business interest expense	17.2	10.4
Other non-current deferred tax assets	1.2	4.5
Total non-current deferred tax assets	112.9	104.3
Valuation allowance	(6.3)	(5.1)
Total deferred tax assets	106.6	99.2
Deferred tax liabilities:
Intangible assets	47.1	46.2
Property and equipment	63.2	57.3
Deferred revenue	16.6	15.0
Prepaid assets	0.1	0.2
Lease assets	20.7	22.0
Other non-current deferred tax liabilities	1.5	6.0
Total non-current deferred tax liabilities	149.2	146.7
Total net deferred tax liabilities	42.6	47.5
Classification on balance sheets:
Other assets	1.3	3.6
Deferred tax liabilities	$ 43.9	$ 51.1