Amount the entity estimates it is due from a customer in excess of the amount paid by the customer.

No definition available.

Name:	ar_AdditionalAccountsReceivable
Namespace Prefix:	ar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Volume of natural gas customer is under contract to purchase,

+ References

No definition available.

+ Details

Name:	ar_NaturalGasLongTermPurchaseContractVolume
Namespace Prefix:	ar_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Volume of natural gas customer is under contract to purchase after specified events have occurred.

+ References

No definition available.

+ Details

Name:	ar_NaturalGasLongTermPurchaseContractVolumeAfterSpecifiedEventsHaveOccurred
Namespace Prefix:	ar_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Increase in volume of natural gas customer is under contract to purchase after specified events have occurred.

+ References

No definition available.

+ Details

Name:	ar_NaturalGasLongTermPurchaseContractVolumeIncreaseAfterSpecifiedEventsHaveOccurred
Namespace Prefix:	ar_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of lawsuits to which the entity is a plaintiff related to a sales contract.

+ References

No definition available.

+ Details

Name:	ar_NumberOfLawsuits
Namespace Prefix:	ar_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of long term gas contracts.

+ References

No definition available.

+ Details

Name:	ar_NumberOfLongTermGasContracts
Namespace Prefix:	ar_
Data Type:	xbrli:integerItemType
Balance Type:	na
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

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

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

+ Details

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

- Details

Name:	us-gaap_LitigationCaseAxis=ar_SouthJerseyGasCompanyAndSouthJerseyResourcesGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=ar_WashingtonGasLightCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GainContingenciesByNatureAxis=us-gaap_PositiveOutcomeOfLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Contingencies (Details) $ in Millions	3 Months Ended	4 Months Ended	11 Months Ended	25 Months Ended
Contingencies (Details) $ in Millions	Mar. 31, 2018 USD ($) MMBTU / d contract lawsuit	Nov. 30, 2017 MMBTU / d	Dec. 31, 2018 MMBTU / d	Jan. 31, 2018 MMBTU / d	Jan. 01, 2019 MMBTU / d	Mar. 31, 2017 USD ($)
SJGC
Contingencies
Natural gas long term purchase contract volume (in MMBtu)/day	80,000
WGL
Contingencies
Natural gas long term purchase contract volume (in MMBtu)/day		600,000	200,000	500,000
Natural gas long term purchase contract volume increase after specified events (in MMBtu)/day					330,000
Natural gas long term purchase contract volume after specified events (in MMBtu)/day					530,000
WGL \| Pending Litigation \| Minimum
Contingencies
Damages sought \| $						$ 30
Potential Positive Outcome of Litigation \| SJGC
Contingencies
Number of lawsuits \| lawsuit	2
Number of long term gas contracts \| contract	2
Potential Positive Outcome of Litigation \| SJGC \| Pending Litigation
Contingencies
Additional accounts receivable \| $	$ 77
Potential Positive Outcome of Litigation \| WGL
Contingencies
Additional accounts receivable \| $	$ 105