Business Combinations - Schedule of Aggregate Cash Consideration and Total Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Business Acquisition [Line Items]
Inventories	$ 0.4	$ 0.3
Property, plant and equipment (a)	5.9	7.6
Operating lease assets	6.1	8.9
Goodwill (b)	21.1	34.3
Intangible assets (c)
Other current liabilities (a)	(0.6)	(0.6)
Operating lease liabilities	(5.7)	(8.3)
Other noncurrent liabilities (a)	(3.6)	(0.4)
Total net assets acquired	27.8	42.7
Finance lease assets	$ 3.8	$ 0.4
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Finance lease liabilities, current	$ 0.2
Finance lease liabilities, noncurrent	$ 3.6	$ 0.4
Weighted average amortization period	9 years	7 years
Reacquired franchise rights (d)
Business Acquisition [Line Items]
Intangible assets (c)	$ 4.0	$ 0.6
Weighted average amortization period	9 years	8 years
Gain (Loss) on Contract Termination	$ 0.0
Other
Business Acquisition [Line Items]
Intangible assets (c)	$ 0.2	$ 0.3