Net 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		9 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income from continuing operations	$ 36.5	$ 33.7	$ 79.4	$ 87.1
Income (loss) from discontinued operations, net of taxes	0.2	(0.1)	0.0	1.0
Net income	$ 36.8	$ 33.6	$ 79.4	$ 88.1
Weighted-average common and common equivalent shares outstanding — Basic (in shares)	66.6	66.1	66.5	66.0
Effect of dilutive securities
Weighted-average common and common equivalent shares outstanding — Diluted (in shares)	67.0	66.3	66.8	66.3
Net income per common share — Basic
Income from continuing operations (in usd per share)	$ 0.55	$ 0.51	$ 1.19	$ 1.32
Income from discontinued operations (in usd per share)	0	0	0	0.02
Net income (in usd per share)	0.55	0.51	1.19	1.33
Net income per common share — Diluted
Income from continuing operations (in usd per share)	0.55	0.51	1.19	1.31
Income from discontinued operations (in usd per share)	0	0	0	0.02
Net income (in usd per share)	$ 0.55	$ 0.51	$ 1.19	$ 1.33
Restricted stock units
Effect of dilutive securities
Effect of dilutive securities (in shares)	0.2	0.1	0.2	0.1
Stock options
Effect of dilutive securities
Effect of dilutive securities (in shares)	0.1	0.1	0.1	0.1