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 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts $ (27,038) $ 21,809 $ 97,966 $ (31,415)
Not Designated as Hedging Instrument        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 27,038 (21,809) (97,966) 31,415
Not Designated as Hedging Instrument | (Gain) loss on contingent consideration arrangements        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 715 4,236 (855) 923
Not Designated as Hedging Instrument | Commodity - Oil        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 16,606 (24,722) (118,348) 34,798
Not Designated as Hedging Instrument | Commodity - Natural gas        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts 7,296 (1,323) 18,819 (4,306)
Not Designated as Hedging Instrument | Commodity - Natural gas liquids        
Derivative Instruments, Gain (Loss) [Line Items]        
(Gain) loss on derivative contracts $ 2,421 $ 0 $ 2,418 $ 0