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BASIS OF PRESENTATION, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND LIQUIDITY, MANAGEMENT'S PLANS AND GOING CONCERN - Narrative (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Aug. 05, 2020
Error Corrections and Prior Period Adjustments Restatement [Line Items] |  |  |
Net cash provided by (used in) operating activities | $ 247,222 | $ 399,769 |
Adjusted to increase net cash flows provided by investing activities | $ (230,090) | (510,225) |
Subsequent Event |  |  |
Error Corrections and Prior Period Adjustments Restatement [Line Items] |  |  |
Percentage of employees transitioned back to the corporate office after COVID-19 |  |  | 60.00%
Misclassification between Operation and Financing Activities |  |  |
Error Corrections and Prior Period Adjustments Restatement [Line Items] |  |  |
Net cash provided by (used in) operating activities |  | 90,800 |
Adjusted to increase net cash flows provided by investing activities |  | $ 90,800 |

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