Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS (Gain and Loss on Derivative Instruments) (Details)

v3.21.1
DERIVATIVE INSTRUMENTS (Gain and Loss on Derivative Instruments) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Derivative [Line Items]    
Net (loss) gain on natural gas, oil and NGL derivatives $ (29,978) $ 98,266
Natural gas derivatives    
Derivative [Line Items]    
Net (loss) gain on natural gas, oil and NGL derivatives (25,413) 45,853
Oil derivatives    
Derivative [Line Items]    
Net (loss) gain on natural gas, oil and NGL derivatives (1,731) 52,874
NGL derivatives    
Derivative [Line Items]    
Net (loss) gain on natural gas, oil and NGL derivatives (2,834) 920
Contingent consideration arrangement    
Derivative [Line Items]    
Net (loss) gain on natural gas, oil and NGL derivatives $ 0 $ (1,381)