Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Derivative Instruments and Hedging Activities (Schedule of Gain or Loss on Derivative Contracts) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]    
Gain (loss) on derivative contracts $ 251,969 $ (67,260)
Not Designated as Hedging Instrument    
Derivative Instruments, Gain (Loss) [Line Items]    
Gain (loss) on derivative contracts 251,969 (67,260)
Not Designated as Hedging Instrument | Gain on contingent consideration arrangements    
Derivative Instruments, Gain (Loss) [Line Items]    
Gain (loss) on derivative contracts 1,475 0
Not Designated as Hedging Instrument | Commodity - Oil    
Derivative Instruments, Gain (Loss) [Line Items]    
Gain (loss) on derivative contracts 257,323 (68,369)
Not Designated as Hedging Instrument | Commodity - Natural gas    
Derivative Instruments, Gain (Loss) [Line Items]    
Gain (loss) on derivative contracts $ (6,829) $ 1,109