STOCK-BASED COMPENSATION - Summary of Activity under Company's Stock Option Plans (Details) - $ / shares shares in Thousands	3 Months Ended		12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Jan. 31, 2021
STOCK-BASED COMPENSATION
Shares, Outstanding, Beginning balance	1,405
Shares, Granted	32
Shares, Exercised	(26)
Shares, Forfeited	(3)
Shares, Outstanding, Ending balance	1,408	1,431	1,405
Shares, Exercisable	1,029	874
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 44.17
Weighted Average Exercise Price, Granted	54.60
Weighted Average Exercise Price, Exercised	39.37
Weighted Average Exercise Price, Forfeited	42.31
Weighted Average Exercise Price, Outstanding, Ending balance	44.50	$ 43.69	$ 44.17
Weighted Average Exercise Price, Exercisable	$ 45.47	$ 45.78
Weighted Average Remaining Term (Years), Outstanding	6 years 9 months 7 days	7 years 3 months 29 days	6 years 10 months 24 days
Weighted Average Remaining Term (Years), Exercisable	6 years 3 days	6 years 2 months 1 day
Weighted Average Fair Value, Outstanding	$ 10.44	$ 10.45	$ 10.39
Weighted Average Fair Value, Exercisable	$ 11.24	$ 11.74