Name:	amgp_BusinessAcquisitionCashPerUnitWithoutInterest
Namespace Prefix:	amgp_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The number of issued, fully paid, non assessable shares of new entity's common stock for each of the Partnership's common units held.

No definition available.

Name:	amgp_BusinessAcquisitionNumberOfNewSharesIssuedForEachCommonSharesHeld
Namespace Prefix:	amgp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The percentage of shares that are fully vested.

No definition available.

Name:	amgp_PercentageOfSharesFullyVested
Namespace Prefix:	amgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The percentage of shares that are scheduled to vest at the end of the current year.

No definition available.

Name:	amgp_PercentageOfSharesScheduledToVestAtEndOfCurrentYear
Namespace Prefix:	amgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The percentage of shares that are scheduled to vest at the end of the next year.

No definition available.

Name:	amgp_PercentageOfSharesScheduledToVestAtEndOfNextYear
Namespace Prefix:	amgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Average threshold day volume-weighted average trading price per entity's common share prior to the final election day for AM Public Unitholders.

No definition available.

Name:	amgp_ThresholdDaysForWeightedAverageTradingPrice
Namespace Prefix:	amgp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The number of new shares issued in the conversion of stock in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Name:	us-gaap_ConversionOfStockSharesIssued1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

Name:	us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_TypeOfArrangementAxis=amgp_SimplificationAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=amgp_AnteroResourcesCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=amgp_AmPublicUnitholdersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: