STOCK-BASED COMPENSATION - Summary of Change in Number of Non-Vested Options to Purchase Shares of Common Stock (Details) - $ / shares shares in Thousands	9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016
STOCK-BASED COMPENSATION
Shares, Non-vested, Beginning balance	270	300
Shares, Granted	125	105
Shares, Vested	(105)	(240)
Shares, Forfeited	(10)
Shares, Non-vested, Ending balance	280	165
Weighted Average Fair Value, Non-vested, Beginning balance	$ 14.93	$ 8.97
Weighted Average Fair Value, Granted	16.19	9.66
Weighted Average Fair Value, Vested	9.66	7.63
Weighted Average Fair Value, Forfeited	19.14
Weighted Average Fair Value, Non-vested, Ending balance	$ 17.83	$ 9.17