REVENUE RECOGNITION - Summary of Contract Assets and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Receivables	$ 182,165	$ 145,413
Short-term contract assets (Prepaid expenses and other assets)	17,879	15,055
Long-term contract assets (Other assets)	51,986	42,087
Short-term contract liabilities (Deferred revenues)	47,665	81,783
Long-term contract liabilities (Deferred revenues)	$ 125,473	$ 100,204