RESTRUCTURING CHARGES - Narrative (Details) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) Employee	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 193			$ 62	$ 466
Restructuring plans | plan							2
Restructuring costs addition					$ 100
VSP
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$ 17,300
Number of employees terminated | Employee				155
VSP | Employee-Related
Restructuring Cost and Reserve [Line Items]
Restructuring charges						100
Q2FY20 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 500
Q2FY20 Plan | Employee-Related
Restructuring Cost and Reserve [Line Items]
Restructuring charges						$ 300
Q4FY20 Plan | Employee-Related
Restructuring Cost and Reserve [Line Items]
Restructuring charges							$ 2,100