Income Taxes - Narrative (Details) $ in Millions	12 Months Ended
	Oct. 31, 2017 USD ($) state	Oct. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)
Income Taxes [Line Items]
Tax benefit related to lapse of statute of limitations	$ 17.8	$ 20.8
Interest on income taxes	1.2	0.6
Work opportunity tax credit, new hires		6.7
Work opportunity tax credit, adjustment		5.1
Tax benefit related to share-based compensation	3.6	2.2
Income tax benefit related to deduction for energy efficient government buildings	1.9	1.2
Tax credits	25.1
Unrecognized tax benefits that would impact effective tax rate	50.5	52.0	$ 75.6
Maximum decrease in unrecognized tax benefits that is reasonably possible	12.2
Uncertain tax positions, interest and penalties accrued	1.9	2.3
Unrecognized tax benefits, interest and penalties benefit	$ 0.5	$ 0.9
Uncertain tax positions, interest and penalties recognized and expensed			$ 1.0
Number of states in which entity operates | state	50
State and Local Jurisdiction
Income Taxes [Line Items]
Operating loss carryforwards	$ 208.4
Federal
Income Taxes [Line Items]
Operating loss carryforwards	$ 56.8