Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.2
DERIVATIVE INSTRUMENTS (Gain and Loss on Derivative Instruments) (Details) - USD ($)
$ in Thousands
 1 Months Ended 2 Months Ended 3 Months Ended 5 Months Ended 6 Months Ended
Jun. 30, 2021
May 17, 2021
Jun. 30, 2020
May 17, 2021
Jun. 30, 2020
Derivative [Line Items]          
Net (loss) gain on natural gas, oil and NGL derivatives $ (139,658) $ (107,261) $ 26,971 $ (137,239) $ 125,237
Natural gas derivatives          
Derivative [Line Items]          
Net (loss) gain on natural gas, oil and NGL derivatives (126,953) (101,029) 35,689 (126,442) 81,542
Oil derivatives          
Derivative [Line Items]          
Net (loss) gain on natural gas, oil and NGL derivatives (5,357) (4,395) (7,937) (6,126) 44,937
NGL derivatives          
Derivative [Line Items]          
Net (loss) gain on natural gas, oil and NGL derivatives (7,348) $ (1,837) $ (781) (4,671) 139
Contingent consideration arrangement          
Derivative [Line Items]          
Net (loss) gain on natural gas, oil and NGL derivatives $ 0     $ 0 $ (1,381)