Income Taxes - Components of Net Deferred Tax Asset and Liability Accounts (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Deferred tax assets:
Interest rate swaps	$ 3.3	$ 4.9
Self-insurance reserves	27.4	23.7
Deferred compensation	2.7	2.8
Deferred rent		0.4
Payroll related accruals	15.8	11.2
Other accrued expenses	5.1	2.3
Allowance for doubtful accounts	0.8	1.3
Lease liabilities	16.6
Net operating loss carryforward	5.5	5.0
Other non-current deferred tax assets	2.3	0.9
Total non-current deferred tax assets	79.5	52.5
Total deferred tax assets	79.5	52.5
Deferred tax liabilities:
Intangible assets	53.2	60.9
Property and equipment	42.3	42.8
Inventories		4.7
Deferred revenue	7.1	7.8
Prepaid assets	0.5	0.3
Lease assets	14.8
Other non-current deferred tax liabilities	0.5	0.4
Total non-current deferred tax liabilities	118.4	116.9
Total deferred tax liabilities	$ 38.9	$ 64.4