STOCK-BASED COMPENSATION - Summary of Activity under Company's Stock Option Plans (Details) - $ / shares shares in Thousands			6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jul. 31, 2019	Jul. 31, 2018
STOCK-BASED COMPENSATION
Shares, Outstanding, Beginning balance				1,140
Shares, Granted			92	97
Shares, Exercised			(59)	(1)
Shares, Forfeited			(38)
Shares, Exercisable			729	712
Shares, Outstanding, Ending balance	1,140	889	1,135	985
Weighted Average Exercise Price, Outstanding, Beginning balance				$ 44.01
Weighted Average Exercise Price, Granted			$ 50.30	37.60
Weighted Average Exercise Price, Exercised			26.36	17.33
Weighted Average Exercise Price, Forfeited			46.34
Weighted Average Exercise Price, Exercisable			45.90	44.50
Weighted Average Exercise Price, Outstanding, Ending balance	$ 44.01	$ 44.83	$ 45.37	$ 44.15
Weighted Average Remaining Term (Years), Outstanding	7 years 6 months 15 days	7 years 10 months 28 days	7 years 4 months 10 days	7 years 7 months 24 days
Weighted Average Remaining Term (Years), Exercisable			6 years 4 months 28 days	6 years 11 months 1 day
Weighted Average Fair Value, Outstanding	$ 11.22	$ 11.74	$ 11.45	$ 11.45
Weighted Average Fair Value, Exercisable			$ 11.97	$ 11.76