Business And Summary Of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016	Jan. 31, 2017
Accounting Policies [Abstract]
Accounts receivable sold	$ 672.4		$ 672.4		$ 506.7
Discount fees on sale of accounts receivable	$ 1.8	$ 1.6	$ 5.9	$ 4.3