LONG-TERM DEBT - Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020	Apr. 09, 2021	Jun. 18, 2014
2021 Notes
Debt Instrument [Line Items]
Interest expense at coupon or contractual rate	$ 639	$ 0	$ 0
Amortization of deferred debt issuance costs	1,416	0	0
Total interest expense	2,055	0	0
Coupon interest rate				0.25%
2014 Notes
Debt Instrument [Line Items]
Interest expense at coupon or contractual rate	1,933	5,887	6,000
Amortization of debt discounts	0	12,884	12,490
Amortization of deferred debt issuance costs	522	1,215	1,177
Total interest expense	2,455	19,986	19,667
Coupon interest rate					1.50%
2017 Credit Agreement
Debt Instrument [Line Items]
Interest expense at coupon or contractual rate	3,366	13,018	18,021
Impact of interest rate swap agreement	1,014	4,368	792
Amortization of debt discounts	18	74	68
Amortization of deferred debt issuance costs	930	1,811	1,569
Total interest expense	$ 5,328	$ 19,271	$ 20,450