Net Income Per Common Share - Calculations of Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2015		Oct. 31, 2014		Oct. 31, 2013
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income from continuing operations	$ 22.6	$ 1.2	$ 16.0	$ 14.3	$ 25.2	$ 17.3	$ 13.3	$ 11.1	$ 54.1		$ 66.9		$ 62.6
Income from discontinued operations, net of taxes	16.2	0.3	2.3	3.4	2.7	2.1	1.9	2.0	22.2	[1]	8.7	[1]	10.3	[1]
Net income	$ 38.8	$ 1.5	$ 18.3	$ 17.7	$ 27.9	$ 19.4	$ 15.2	$ 13.1	$ 76.3		$ 75.6		$ 72.9
Weighted-average common and common equivalent shares outstanding—Basic (in shares)									56.7		56.1		54.9
Effect of dilutive securities:
Weighted-average common and common equivalent shares outstanding—Diluted (in shares)									57.4		57.1		56.1
Net income per common share — Basic:
Income from continuing operations (in usd per share)	$ 0.39	$ 0.02	$ 0.28	$ 0.25	$ 0.45	$ 0.30	$ 0.24	$ 0.19	$ 0.95		$ 1.19		$ 1.14
Income from discontinued operations (in usd per share)	0.29	0.01	0.04	0.06	0.05	0.04	0.03	0.04	0.40		0.16		0.19
Net income per common share-Basic (in usd per share)	0.68	0.03	0.32	0.31	0.50	0.34	0.27	0.23	1.35		1.35		1.33
Net income per common share — Diluted:
Income from continuing operations (in usd per share)	0.39	0.02	0.28	0.25	0.44	0.30	0.24	0.19	0.94		1.17		1.12
Income from discontinued operations (in usd per share)	0.29	0.01	0.04	0.06	0.05	0.04	0.03	0.04	0.39		0.15		0.18
Net income per common share-Diluted (in usd per share)	$ 0.68	$ 0.03	$ 0.32	$ 0.31	$ 0.49	$ 0.34	$ 0.27	$ 0.23	$ 1.33		$ 1.32		$ 1.30
RSUs
Effect of dilutive securities:
Effect of dilutive securities									0.3		0.4		0.5
Performance shares
Effect of dilutive securities:
Effect of dilutive securities									0.3		0.4		0.3
Stock options
Effect of dilutive securities:
Effect of dilutive securities									0.1		0.2		0.4

[1] Discontinued operations includes both costs related to ongoing legal cases and insurance reserves associated with the former Security business. We will continue to reflect these types of costs within discontinued operations in future periods. Refer to Note 15, “Commitments and Contingencies,” and Note 12, “Insurance,” for further information.