STOCK-BASED COMPENSATION - Summary of Change in Number of Non-Vested Options to Purchase Shares of Common Stock (Details) - $ / shares shares in Thousands	6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
STOCK-BASED COMPENSATION
Shares, Non-vested, Beginning balance	270	300
Shares, Granted	125	105
Shares, Vested	(105)	(135)
Shares, Forfeited	(10)
Shares, Non-vested, Ending balance	280	270
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	8.99
Weighted Average Fair Value, Forfeited	19.14
Weighted Average Fair Value, Non-vested, Ending balance	$ 17.83	$ 9.22