Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	$ (73,437)	$ 4,969
Net derivative (gain) loss	(545,340)	177,081
Oil Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(53,582)	1,369
Net derivative (gain) loss	(542,540)	185,797
Gas Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(14,625)	4,134
Net derivative (gain) loss	6,728	(6,113)
NGL Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(5,230)	(534)
Net derivative (gain) loss	$ (9,528)	$ (2,603)