Selected Quarterly Financial Data (Unaudited) (Detail) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 1,277.0	$ 1,249.9	$ 1,176.4	$ 1,194.5	$ 1,204.7	$ 1,180.7	$ 1,137.5	$ 1,126.8	$ 4,897.8	[1]	$ 4,649.7	[1]	$ 4,427.8	[1]
Gross profit	148.9	93.6	123.8	121.5	133.7	124.0	120.8	110.7
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	[2]	8.7	[2]	10.3	[2]
Net income	$ 38.8	$ 1.5	$ 18.3	$ 17.7	$ 27.9	$ 19.4	$ 15.2	$ 13.1	$ 76.3		$ 75.6		$ 72.9
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

[1] Substantially all of our long-lived assets are related to United States operations.

[2] 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.