LONG-TERM DEFERRED REVENUE LIABILITIES AND OTHER LONG-TERM LIABILITIES - Schedule of Deferred Revenue Liabilities and Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Long-term Purchase Commitment [Line Items]
Long-term deferred revenue liabilities	$ 36,920	$ 52,500
Other	0	13
Total long-term deferred revenue liabilities and other long-term liabilities	73,749	52,513
WLR
Long-term Purchase Commitment [Line Items]
Long-term deferred revenue liabilities	13,061	0
WLWI
Long-term Purchase Commitment [Line Items]
Long-term deferred revenue liabilities	$ 23,768	$ 0