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Derivatives - Narrative (Details) bbl in Thousands, $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($) institution $ / Unit	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Dec. 31, 2018 USD ($) institution $ / Unit bbl	Dec. 31, 2017 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts	$ (42,600)	$ 11,300	$ 30,100	$ 18,300	$ 21,900	$ 11,700	$ (23,500)	$ (34,200)
Number of counterparties to open derivative contracts | institution	4										4
Commodity Derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts											$ 17,200	$ (24,100)
Payments for (proceeds from) settlement of derivative contracts											35,300	(7,300)
Payment for early settlements											800
Successor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts									$ 25,652		17,155	(24,090)
Payments for (proceeds from) settlement of derivative contracts									(7,698)		$ 35,325	$ (7,260)
Successor | Commodity Derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts									25,700
Payments for (proceeds from) settlement of derivative contracts									$ (7,700)
Predecessor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts										$ 4,823
Payments for (proceeds from) settlement of derivative contracts										(72,608)
Predecessor | Commodity Derivatives
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss (gain) on derivative contracts										4,800
Payments for (proceeds from) settlement of derivative contracts										(72,600)
Derivative, cash received on early settlement										$ (17,900)
2018 Production
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional (MMcf) | bbl											9
Strike price (in dollars per unit) | $ / Unit	56.12										56.12
2019 Production
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional (MMcf) | bbl											5
Strike price (in dollars per unit) | $ / Unit	54.29										54.29

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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Nominal volume used to calculate payments on a derivative instrument.

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Number Of Counterparties To Open Derivative Contracts

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The net cash outflow or inflow from derivatives instruments during the period, which are classified as operating activities, excluding those designated as hedging instruments.

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