Business And Summary Of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016	Jan. 31, 2017
Accounting Policies [Abstract]
Accounts receivable sold	$ 634.0		$ 634.0		$ 506.7
Discount fees on sale of accounts receivable	$ 2.3	$ 1.5	$ 4.1	$ 2.7