REVENUE RECOGNISION - Summary of Contract Assets and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Receivables	$ 55,622	$ 65,346
Short-term contract assets (Prepaid expenses and other assets)	13,896
Long-term contract assets (Other assets)	33,762
Short-term contract liabilities (Deferred revenues, current)	37,408	15,691
Long-term contract liabilities (Deferred revenues, noncurrent)	$ 78,265	$ 29,941