Contingencies (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015 lawsuit	Feb. 04, 2015 lawsuit
Contingencies
Number of lawsuits	1ar_NumberOfLawsuits	2ar_NumberOfLawsuits
Additional accounts receivable	$ 14.3ar_AdditionalAccountsReceivable

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

No definition available.

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