STOCK-BASED COMPENSATION - Summary of Activity under Company's Stock Option Plans (Details) - $ / shares shares in Thousands	9 Months Ended		12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
STOCK-BASED COMPENSATION
Shares, Outstanding, Beginning balance	1,064	876	876
Shares, Granted	105	240
Shares, Exercised	(444)	(96)
Shares, Forfeited	(5)	(6)
Shares, Outstanding, Ending balance	720	1,014	1,064	876
Shares, Exercisable	555	689
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 26.38	$ 22.34	$ 22.34
Weighted Average Exercise Price, Granted	36.09	35.76
Weighted Average Exercise Price, Exercised	24.77	17.31
Weighted Average Exercise Price, Forfeited	36.73	17.33
Weighted Average Exercise Price, Outstanding, Ending balance	28.71	26.03	$ 26.38	$ 22.34
Weighted Average Exercise Price, Exercisable	$ 27.13	$ 2,192.00
Weighted Average Remaining Term, Outstanding	7 years 2 months 16 days	6 years 11 months 23 days	6 years 4 months 10 days	7 years 29 days
Weighted Average Remaining Term, Exercisable	6 years 6 months 18 days	6 years 4 months 2 days
Weighted Average Fair Value, Outstanding	$ 7.62	$ 6.82	$ 6.91	$ 6.01
Weighted Average Fair Value, Exercisable	$ 7.16	$ 5.81