Business And Summary Of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Jan. 31, 2018
Accounting Policies [Abstract]
Accounts receivable sold	$ 924.6		$ 924.6		$ 687.2
Discount fees on sale of accounts receivable	$ 4.1	$ 1.8	$ 10.5	$ 5.9