Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Millions		12 Months Ended
	Sep. 30, 2021	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2019
Business Acquisition [Line Items]
Goodwill		$ 2,228.9	$ 1,671.4	$ 1,835.4
Amortization period for acquired intangible assets		12 years	12 years
Able
Business Acquisition [Line Items]
Cash and cash equivalents	$ 31.5
Trade accounts receivable	159.3
Other assets	24.9
Goodwill	554.0
Trade accounts payable	(27.0)
Accrued compensation	(38.2)
Insurance claims	(91.6)
Other liabilities	(41.7)
Deferred income tax liability, net	(59.5)
Net assets acquired	741.7
Trade accounts receivable, gross		$ 160.6
Estimated uncollectible trade accounts receivable		$ 1.4
Able | Customer relationships
Business Acquisition [Line Items]
Intangible assets	$ 220.0
Amortization period for acquired intangible assets	15 years
Able | Trade names
Business Acquisition [Line Items]
Intangible assets	$ 10.0
Amortization period for acquired intangible assets	2 years