Basis of Presentation Reclassification (Details) $ in Millions	3 Months Ended				6 Months Ended		9 Months Ended
	Oct. 31, 2016 USD ($) segment	Apr. 30, 2016 USD ($)	Oct. 31, 2015 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2016 ReportingUnits segment	Jul. 31, 2015 USD ($)	Oct. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1				4
Number of reportable segments | segment					4
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes	$ 13.5	$ (14.4)	$ 21.3	$ 269.5		$ 272.2	$ 53.1	$ 293.5
Operating expenses	$ 528.0		$ 523.6				$ 1,625.7	1,569.0
Employee Benefits and Estimated Personal Property Liabilities
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating expenses								$ 5.7
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Provision for income taxes				$ 33.1		$ 33.1