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Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	$ (351,261)	$ (39,222)	$ 135,803
Net derivative (gain) loss	(161,576)	97,539	(161,832)
Oil Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(331,559)	19,685	68,860
Net derivative (gain) loss	(205,180)	172,055	(192,002)
Gas Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(11,898)	(23,008)	13,029
Net derivative (gain) loss	30,038	(41,205)	35,411
NGL Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(7,804)	(35,899)	53,914
Net derivative (gain) loss	$ 13,566	$ (33,311)	$ (5,241)

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- Definition

Realized gain or loss recognized in earnings from the settlement of derivative instruments not designated as hedges.

+ References

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- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959

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