SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 380,373	$ 285,746
Restricted cash (1)	373	369
Total cash, cash equivalents, and restricted cash	$ 380,746	$ 286,115	$ 300,223	$ 492,686