Commitment And Contingencies [Line Items]

No definition available.

Name:	amr_CommitmentAndContingenciesLineItems
Namespace Prefix:	amr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Long-Term Purchase Commitment, Minimum Payment Shortfall Volume Payment Required

+ References

No definition available.

+ Details

Name:	amr_LongTermPurchaseCommitmentMinimumPaymentShortfallVolumePaymentRequired
Namespace Prefix:	amr_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

+ Details

Name:	us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Energy volume that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermPurchaseCommitmentMinimumEnergyVolumeRequired
Namespace Prefix:	us-gaap_
Data Type:	num:energyItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=amr_KingfisherMidstreamLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ReserveQuantitiesByTypeOfReserveAxis=srt_NaturalGasReservesMember
Namespace Prefix:
Data Type:	na
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COMMITMENTS AND CONTINGENCIES (Narrative) (Details) Mcfe in Thousands, $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Feb. 08, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) Mcfe $ / MMcf
Commitment And Contingencies [Line Items]
General and administrative	$ 21,234	$ 131,052	$ 107,655
Performance Shares
Commitment And Contingencies [Line Items]
General and administrative		$ 10,900
KFM Credit Facility
Commitment And Contingencies [Line Items]
Commitment amount			$ 128
Natural gas \| KFM Credit Facility
Commitment And Contingencies [Line Items]
Processing commitment \| Mcfe			3,650
Shortfall volume commitment amount \| $ / MMcf			0.85