COMMITMENTS AND CONTINGENCIES - RENT EXPENSE; PURCHASE OBLIGATIONS AND OFF-BALANCE SHEET RISK (Details) $ in Millions	12 Months Ended
	Jan. 31, 2018 USD ($) mo	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)
Operating Leases, Rent Expense, Net [Abstract]
Rent expenses incurred under all operating leases	$ 26.1	$ 25.6	$ 19.4
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	0.4
Minimum annual sublease rental income	0.1
Maximum annual sublease rental income	0.3
Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]
Unconditional purchase obligations	$ 109.4
Unconditional purchase obligations, subsequent fulfillment period (in months) | mo	12
Concentration Risks, Types, No Concentration Percentage [Abstract]
Outstanding letters of credit and surety bonds	$ 92.5