STOCK-BASED COMPENSATION - Summary of Change in Number of Non-Vested Options to Purchase Shares of Common Stock (Details) - $ / shares shares in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
STOCK-BASED COMPENSATION
Shares, Nonvested, Beginning balance	300	306	303
Shares, Granted	270	300	306
Shares, Vested	(300)	(306)	(303)
Shares, Nonvested, Ending balance	270	300	306
Weighted Average Fair Value, Nonvested, Beginning balance	$ 8.97	$ 7.14	$ 4.40
Weighted Average Fair Value, Granted	14.93	8.97	7.14
Weighted Average Fair Value, Vested	8.97	7.14	4.40
Weighted Average Fair Value, Nonvested, Ending balance	$ 14.93	$ 8.97	$ 7.14