Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Income Tax Disclosure [Abstract]
Income tax benefit related to expiring statute of limitations	$ 15.8	$ 19.0	$ 15.8	$ 19.0
Unrecognized tax benefits, interest on income taxes	$ 1.2	1.0	1.2	1.0
Income tax benefit related to vesting of share-based compensation awards		$ 1.8	2.7	1.8
Income tax benefit related to deduction for energy efficient government buildings			$ 1.8	1.2
Income tax benefit related to Work Opportunity Tax Credit				$ 4.9