REVENUE RECOGNITION - Schedule of Assets and Liabilities Associated with Contracts from Customers (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Accounts receivable	$ 96,235	$ 82,261
Short-term deferred revenue	123,475	105,215
Long-term deferred revenue	43,458	$ 57,086
Other Current Assets [Member]
Disaggregation Of Revenue [Line Items]
Short-term unbilled receivables	27,491
Other Assets [Member]
Disaggregation Of Revenue [Line Items]
Long-term unbilled receivables	$ 0