Income Taxes - Components of Net Deferred Tax Asset and Liability Accounts (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Deferred tax assets:
Self-insurance reserves	$ 37.6	$ 37.3
Deferred compensation	1.8	2.2
Payroll related accruals	23.5	25.3
Allowance for doubtful accounts	2.5	2.5
Lease liabilities	19.8	22.3
Net operating loss carryforward	8.2	4.9
Business interest expense	31.1	17.2
Other non-current deferred tax assets	1.3	1.2
Total non-current deferred tax assets	125.8	112.9
Valuation allowance	(9.3)	(6.3)
Total deferred tax assets	116.5	106.6
Deferred tax liabilities:
Intangible assets	49.3	47.1
Property and equipment	96.6	63.2
Deferred revenue	14.5	16.6
Prepaid assets	0.3	0.1
Lease assets	18.2	20.7
Other non-current deferred tax liabilities	1.4	1.5
Total non-current deferred tax liabilities	180.3	149.2
Total net deferred tax liabilities	63.8	42.6
Classification on balance sheets:
Other assets	0.0	1.3
Deferred tax liabilities	$ 63.8	$ 43.9