Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Oct. 31, 2018	Oct. 31, 2018		Oct. 31, 2017	Oct. 31, 2016
Goodwill [Line Items]
Goodwill impairment (recovery)	[1]		$ 20.3
Technical Solutions
Goodwill [Line Items]
Goodwill impairment (recovery)		$ 20.3	$ 20.3	[1]
Government Services
Goodwill [Line Items]
Goodwill impairment (recovery)					$ (6.0)	$ 6.0

[1] Represents accumulated impairment charges at October 31, 2018.