Debt Instrument, Covenant, Consolidated EBITDA Threshold

No definition available.

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Namespace Prefix:	amr_
Data Type:	xbrli:monetaryItemType
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- Definition

Debt Instrument, Covenant, Current Ratio, Minimum Required

+ References

No definition available.

+ Details

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- Definition

Maximum allowed ratio of total debt to income before interest, income taxes, depreciation, depletion and amortization, and exploration expense, as defined in the credit facility financial covenants.

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Covenant, Maximum Leverage Ratio, Scenario One

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Covenant, Maximum Leverage Ratio, Scenario Two

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Covenant, Minimum Interest Coverage Ratio

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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- Definition

Line Of Credit Facility, Amount Outstanding Exceeding Current Borrowing Base

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No definition available.

+ Details

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Namespace Prefix:	amr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of the required periodic payments of both interest and principal.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Debt (Narrative) (Details)	3 Months Ended	9 Months Ended
Debt (Narrative) (Details)	Mar. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Oct. 31, 2019 USD ($)	Aug. 31, 2019 USD ($)	Apr. 01, 2019 USD ($)
Alta Mesa Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity	$ 400,000,000.0				$ 370,000,000.0
Credit facility amount				$ 200,000,000.0
Amount exceeding borrowing base				$ 162,400,000
Monthly payments	$ 32,500,000
Debt covenant, current ratio, minimum required		1.0
Maximum leverage ratio		4.0
Kingfisher Credit Facility
Debt Instrument [Line Items]
Debt covenant, maximum leverage ratio, scenario one		4.5
Debt covenant, maximum leverage ratio, scenario two		4.75
Debt covenant, consolidated EBITDA threshold		$ 75,000,000.0
Debt covenant, minimum interest coverage ratio		2.5
Amendment To KFM Credit Facility
Debt Instrument [Line Items]
Credit facility amount		$ 15,000,000.0
Alta Mesa RBL \| 2024 Notes
Debt Instrument [Line Items]
Fair value of notes		85,700,000
Kingfisher \| Kingfisher Credit Facility
Debt Instrument [Line Items]
Credit facility amount		$ 300,000.0
Subsequent Event \| Amendment To KFM Credit Facility
Debt Instrument [Line Items]
Remaining borrowing capacity			$ 76,000,000.0