Derivative Financial Instruments Gains and Losses (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]
Derivative settlement (gain) loss	$ (142,528)	$ (4,090)	$ (215,965)	$ 879
Net derivative (gain) loss	167,200	(79,655)	(378,140)	97,426
Oil Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(138,606)	10,689	(192,188)	12,058
Net derivative (gain) loss	151,250	(34,552)	(391,290)	151,245
Gas Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(1,054)	(5,668)	(15,679)	(1,534)
Net derivative (gain) loss	8,261	(25,996)	14,989	(32,109)
NGL Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(2,868)	(9,111)	(8,098)	(9,645)
Net derivative (gain) loss	$ 7,689	$ (19,107)	$ (1,839)	$ (21,710)