SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||||
---|---|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2019 |
Sep. 30, 2018 |
Jan. 01, 2019 |
Dec. 31, 2018 |
Jan. 01, 2018 |
|
Accounting Policies [Abstract] | ||||||
Operating lease right of use assets | $ 37,751 | $ 37,751 | $ 27,384 | $ 0 | $ 0 | |
Operating lease liabilities | $ 43,171 | $ 43,171 | $ 30,300 | $ 0 | ||
Operating Lease, Weighted Average Discount Rate, Percent | 5.795% | 5.795% | ||||
Operating Lease, Payments | $ 2,500 | $ 6,800 | ||||
Operating lease expense | $ 2,500 | $ 6,689 | $ 0 |