Acquisitions - GCA Preliminary Purchase Price Allocation (Details) - USD ($) $ in Millions		9 Months Ended
		Jul. 31, 2018	Oct. 31, 2017
Business Acquisition [Line Items]
Adjustment, trade accounts receivable	[1]	$ (0.4)
Adjustment, prepaid and other current assets		(0.3)
Goodwill		1,864.3	$ 1,864.2
GCA Holding Corp.
Business Acquisition [Line Items]
Cash and cash equivalents		0.2	2.5
Adjustment, Cash and cash equivalents		(2.3)
Trade accounts receivable	[1]	117.7	118.1
Prepaid expenses and other current assets		10.1	10.3
Property, plant and equipment		41.5	41.4
Adjustment, Property, plant and equipment		0.1
Goodwill	[2]	934.2	933.9
Adjustment, Goodwill	[2]	0.3
Other assets		4.0	4.2
Adjustment, Other assets		(0.2)
Trade accounts payable		(9.6)	(9.1)
Adjustment, Trade accounts payable		(0.4)
Insurance reserves		(36.1)	(35.5)
Adjustment, Insurance reserves		(0.6)
Income taxes payable		(8.3)	(16.5)
Adjustment, Income taxes payable		8.2
Accrued liabilities		(33.1)	(36.5)
Adjustment, Accrued liabilities		3.3
Deferred income tax liability, net		(92.6)	(92.6)
Adjustment, Deferred income tax liability, net		0.0
Other liabilities		(8.1)	(8.1)
Net assets acquired		1,258.8	1,261.3
Adjustment, Net assets acquired		(2.4)
Acquired Receivables
Trade accounts receivable, gross		122.0
Estimated uncollectible trade accounts receivable		4.3
GCA Holding Corp. | Customer relationships
Business Acquisition [Line Items]
Intangible assets	[3]	330.0	340.0
Adjustment, Intangible assets	[3]	$ (10.0)
Acquired Intangible Assets
Amortization period for acquired intangible assets		15 years
GCA Holding Corp. | Trade names
Business Acquisition [Line Items]
Intangible assets	[3]	$ 9.0	$ 9.0
Acquired Intangible Assets
Amortization period for acquired intangible assets		2 years

[1] The gross amount of trade accounts receivable was $122.0 million, of which $4.3 million is currently expected to be uncollectible.

[2] Goodwill is largely attributable to value we expect to obtain from long-term business growth, the established workforce, and buyer-specific synergies. This goodwill is not deductible for income tax purposes.

[3] The amortization periods for the acquired intangible assets are 15 years for customer relationships and 2 years for trade names.