OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (NON-CURRENT) - Other Non-Current Assets (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2019 |
Sep. 30, 2018 |
Dec. 31, 2018 |
|
| Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||||
| Marketable equity investment | $ 28,875 | $ 28,875 | $ 45,342 | |
| Non-current lease prepayments | 34,199 | 34,199 | 0 | |
| Other | 18,252 | 18,252 | 13,051 | |
| Total | 81,326 | 81,326 | $ 58,393 | |
| Gain (loss) on equity investment | $ 2,500 | $ (16,467) | $ 36,908 | |