Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities (Schedule of Gain or Loss on Derivative Contracts) (Details)

v3.20.2
Derivative Instruments and Hedging Activities (Schedule of Gain or Loss on Derivative Contracts) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts $ (126,965) $ 14,036 $ 125,004 $ (53,224)
Not Designated as Hedging Instrument        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 126,965 (14,036) (125,004) 53,224
Not Designated as Hedging Instrument | Gain on contingent consideration arrangements        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts (95) (3,313) (1,570) (3,313)
Not Designated as Hedging Instrument | Commodity - Oil        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 122,369 (8,849) (134,954) 59,520
Not Designated as Hedging Instrument | Commodity - Natural gas        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 4,695 (1,874) 11,524 (2,983)
Not Designated as Hedging Instrument | Commodity - Natural gas liquids        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts $ (4) $ 0 $ (4) $ 0