Segment Information - Reconciliation of Segment Information, (Loss) Earnings Before Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment (Loss) Earnings Before Income Taxes for Reportable Business Segments	$ (159,132)	$ 233,485	$ (616,937)	$ 157,275
Other (Expense) Income	(4,799)	99	(9,985)	681
Gain on Certain Asset Sales	5,938	387	17,992	(2,699)
(Loss) Gain on Debt Extinguishment	(344)	(77)	10,919	(7,614)
(Loss) Earnings Before Income Tax	(159,132)	233,485	(616,937)	157,275
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment (Loss) Earnings Before Income Taxes for Reportable Business Segments	(161,967)	232,674	(638,064)	158,828
(Loss) Earnings Before Income Tax	(161,967)	232,674	(638,064)	158,828
Corporate, Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment (Loss) Earnings Before Income Taxes for Reportable Business Segments	2,835	811	21,127	(1,553)
Other (Expense) Income	(4,547)	501	(9,561)	1,531
Gain on Certain Asset Sales	7,726	387	19,769	4,530
(Loss) Gain on Debt Extinguishment	(344)	(77)	10,919	(7,614)
(Loss) Earnings Before Income Tax	2,835	811	21,127	(1,553)
Total E&P \| Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment (Loss) Earnings Before Income Taxes for Reportable Business Segments	(192,263)	188,260	(238,816)	81,830
(Loss) Earnings Before Income Tax	(192,263)	188,260	(238,816)	81,830
Midstream \| Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Segment (Loss) Earnings Before Income Taxes for Reportable Business Segments	30,296	44,414	(399,248)	76,998
(Loss) Earnings Before Income Tax	$ 30,296	$ 44,414	$ (399,248)	$ 76,998

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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Amount of income (expense) related to nonoperating activities, classified as other.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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