Leases - Summary of Lease-Related Assets and Liabilities (Details) - USD ($) $ in Millions		Sep. 30, 2023	Sep. 30, 2022
Operating leases:
Right-of-use asset		$ 86.1	$ 81.6
Current portion of lease liabilities		27.3	26.8
Lease liabilities		65.1	61.3
Total operating lease liabilities		92.4	88.1
Finance leases:
Right-of-use asset	[1]	$ 41.3	$ 41.9
FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList		Property and equipment, net	Property and equipment, net
Current portion of lease liabilities	[2]	$ 21.5	$ 19.3
FinanceLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList		Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Lease liabilities	[3]	$ 21.3	$ 22.4
FinanceLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList		Other liabilities	Other liabilities
Total finance lease liabilities		$ 42.8	$ 41.7

[1] Included in “Property and equipment, net” in the consolidated balance sheets.

[2] Included in “Accrued expenses and other liabilities” in the consolidated balance sheets.

[3] Included in “Other liabilities” in the consolidated balance sheets.