PROPERTY, PLANT AND EQUIPMENT - Depreciation Expense and Cost of Maintenance and Repairs (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
PROPERTY, PLANT AND EQUIPMENT
Depreciation expense	$ 3,422	$ 2,779	$ 2,043
Costs of maintenance and repairs	$ 3,100	$ 2,400	$ 2,300