DERIVATIVE INSTRUMENTS - Net gains and losses recognized on derivatives (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Revenue      
Derivative, Gain (Loss) on Derivative, Net [Abstract]      
Net gains (losses) recognized on economic hedges $ 278 $ 95  
Derivative and warrant fair value adjustment      
Derivative, Gain (Loss) on Derivative, Net [Abstract]      
Net gains (losses) recognized on economic hedges (23,317)    
Other income, net      
Derivative, Gain (Loss) on Derivative, Net [Abstract]      
Net gains (losses) recognized on economic hedges $ (4) $ (773) $ 420