Business acquisition and divestiture.

No definition available.

Name:	ampy_BusinessAcquisitionAndDivestitureLineItems
Namespace Prefix:	ampy_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Merger, conversion ratio, shares in acquirer to be received by acquiree per share of common stock.

+ References

No definition available.

+ Details

Name:	ampy_MergerConversionRatioShares
Namespace Prefix:	ampy_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Net proceeds of divestiture of businesses.

+ References

No definition available.

+ Details

Name:	ampy_NetProceedsOfDivestitureOfBusinesses
Namespace Prefix:	ampy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

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

- Definition

The expenses and losses recorded for each transaction with the acquiree that was recognized separately from the acquisition of assets and assumptions of liabilities in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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

- Definition

The revenues and gains recognized recorded for each transaction with the acquiree that is recognized separately from the acquisition of assets and assumptions of liabilities in the business combination.

+ References

+ Details

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

- Definition

Face amount or stated value per share of common stock.

+ 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(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ampy_SouthTexasDivestitureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ampy_LegacyAmplifyMidstatesAndMidstatesHoldingsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ampy_OklahomaPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OperatingExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions and Divestitures - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			2 Months Ended
	May 05, 2019	May 30, 2018	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Business Acquisition And Divestiture [Line Items]
Merger conversion ratio			0.933
Common stock par value per share			$ 0.01		$ 0.0001
Measurement period adjustment amount of increase asset retirement obligations liability			$ 89,581		$ 76,344
Operating lease - long term right-of-use asset			4,925		$ 0
Operating Liabilities			4,946
Disposal Group Not Discontinued Operation [Member] \| South Texas Divestiture [Member]
Business Acquisition And Divestiture [Line Items]
Total net proceeds from divestitures		$ 17,100
ASU 2016-02 [Member]
Business Acquisition And Divestiture [Line Items]
Operating lease - long term right-of-use asset				$ 5,400
Operating Liabilities				$ 5,400
Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member]
Business Acquisition And Divestiture [Line Items]
Merger conversion ratio	0.933
Common stock par value per share	$ 0.01
Measurement period adjustment amount of increase asset retirement obligations liability			900
Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member] \| ASU 2016-02 [Member]
Business Acquisition And Divestiture [Line Items]
Operating lease - long term right-of-use asset			300
Operating Liabilities			300
Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member] \| Oklahoma Properties [Member]
Business Acquisition And Divestiture [Line Items]
Business acquisition, revenues			12,700
Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member] \| Direct Operating Expense [Member] \| Oklahoma Properties [Member]
Business Acquisition And Divestiture [Line Items]
Business acquisition, expenses			17,700
Legacy Amplify, Midstates and Midstates Holdings, Inc. [Member] \| Other Expenses [Member] \| Oklahoma Properties [Member]
Business Acquisition And Divestiture [Line Items]
Business acquisition, expenses			$ 200