Employee Benefit Plans Estimated Pre-Tax Amount to be Amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost Over Next 12 Months (Details) $ in Millions	Jan. 31, 2018 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 13.2
Prior service cost (credit)	0.1
Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year	13.3
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	0.1
Prior service cost (credit)	(0.7)
Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year	$ (0.6)