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, 2018	Jul. 31, 2017
STOCK-BASED COMPENSATION
Shares, Outstanding, Beginning balance			889	707
Shares, Granted			97	125
Shares, Exercised			(1)	(80)
Shares, Forfeited				(10)
Shares, Outstanding, Ending balance	889	707	985	742
Shares, Exercisable			712	462
Weighted Average Exercise Price, Outstanding, Beginning balance			$ 44.83	$ 39.04
Weighted Average Exercise Price, Granted			37.60	63.58
Weighted Average Exercise Price, Exercised			17.33	30.48
Weighted Average Exercise Price, Forfeited				71.75
Weighted Average Exercise Price, Outstanding, Ending balance	$ 44.83	$ 39.04	44.15	43.66
Weighted Average Exercise Price, Exercisable			$ 44.50	$ 28.84
Weighted Average Remaining Term (Years), Outstanding	7 years 10 months 28 days	7 years 9 months 26 days	7 years 7 months 24 days	7 years 9 months 15 days
Weighted Average Remaining Term (Years), Exercisable			6 years 11 months 1 day	6 years 8 months 19 days
Weighted Average Fair Value, Outstanding	$ 11.74	$ 10.22	$ 11.45	$ 11.56
Weighted Average Fair Value, Exercisable			$ 11.76	$ 7.75