STOCK-BASED COMPENSATION - Summary of Activity under Company's Stock Option Plans (Details) - $ / shares shares in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
STOCK-BASED COMPENSATION
Shares, Outstanding, Beginning balance	1,140	889	707
Shares, Granted	238	257	302
Shares, Exercised	(61)	(6)	(110)
Shares, Forfeited	(46)		(10)
Shares, Exercisable	823
Shares, Outstanding, Ending balance	1,271	1,140	889	707
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 44.01	$ 44.83	$ 39.04
Weighted Average Exercise Price, Granted	44.76	40.54	53.49
Weighted Average Exercise Price, Exercised	26.67	17.19	28.81
Weighted Average Exercise Price, Forfeited	48.47		71.75
Weighted Average Exercise Price, Exercisable	45.58
Weighted Average Exercise Price, Outstanding, Ending balance	$ 44.83	$ 44.01	$ 44.83	$ 39.04
Weighted Average Remaining Term (Years), Outstanding	7 years 2 months 5 days	7 years 6 months 15 days	7 years 10 months 28 days	7 years 9 months 26 days
Weighted Average Remaining Term (Years), Exercisable	6 years 2 months 12 days
Weighted Average Fair Value, Outstanding	$ 11.06	$ 11.22	$ 11.74	$ 10.22
Weighted Average Fair Value, Exercisable	$ 11.78