STOCK-BASED COMPENSATION - Modified Vesting of Shares (Details) - USD ($) $ in Thousands |
6 Months Ended | 9 Months Ended | 12 Months Ended | |
---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Dec. 31, 2018 |
Dec. 31, 2018 |
|
Stock-based compensation | ||||
Stock-based compensation | $ 36,309 | $ 28,056 | ||
Non-cash stock-based compensation expense | $ 3,900 | |||
Former Chief Operating Officer | ||||
Stock-based compensation | ||||
Accelerated vesting, shares | 69,950 | |||
Former Chief Operating Officer | Restricted Shares and RSUs | ||||
Stock-based compensation | ||||
Accelerated vesting, shares | 54,350 |