Net (Loss) Income Per Common Share - Calculations of Basic and Diluted Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
(Loss) income from continuing operations	$ (136.8)	$ 29.9	$ (108.9)	$ 42.9
(Loss) income from discontinued operations, net of taxes	0.0	(0.2)	0.1	(0.2)
Net (loss) income	$ (136.8)	$ 29.7	$ (108.8)	$ 42.7
Weighted-average common and common equivalent shares outstanding — Basic (in shares)	66.9	66.5	66.9	66.4
Effect of dilutive securities(1)
Weighted-average common and common equivalent shares outstanding — Diluted (in shares)	66.9	66.8	66.9	66.7
Net (loss) income per common share — Basic
(Loss) income from continuing operations (in usd per share)	$ (2.05)	$ 0.45	$ (1.63)	$ 0.65
(Loss) income from discontinued operations (in usd per share)	0	0	0	0
Net (loss) income (in usd per share)	(2.05)	0.45	(1.63)	0.64
Net (loss) income per common share — Diluted
(Loss) income from continuing operations (in usd per share)	(2.05)	0.45	(1.63)	0.64
(Loss) income from discontinued operations (in usd per share)	0	0	0	0
Net (loss) income (in usd per share)	$ (2.05)	$ 0.45	$ (1.63)	$ 0.64
Restricted stock units
Effect of dilutive securities(1)
Effect of dilutive securities (in shares)	0.0	0.2	0.0	0.2
Stock options
Effect of dilutive securities(1)
Effect of dilutive securities (in shares)	0.0	0.1	0.0	0.1