REVENUE RECOGNITION - Schedule of Assets and Liabilities Associated with Contracts from Customers (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Accounts receivable	$ 91,327	$ 82,261
Short-term deferred revenue	128,546	105,215
Long-term deferred revenue	49,578	$ 57,086
Other Current Assets [Member]
Disaggregation Of Revenue [Line Items]
Short-term unbilled receivables	$ 24,900