NATURE OF BUSINESS AND BASIS OF PRESENTATION - Nature of Business (Details)	3 Months Ended
	Apr. 30, 2017 segment product location item customer employee
Nature of Business
Number of distinct market sectors in which entity specializes | item	3
Number of operating locations	500
Number of associates | employee	14,000
Number of customers | customer	530,000
Number of SKUs offered | product	845,000
Number of reportable segments | segment	3
U.S.
Nature of Business
Number of states or provinces	48
Canada
Nature of Business
Number of states or provinces	6