Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsNonvestedOutstandingNumber
Namespace Prefix:	epm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsNonvestedRollForward
Namespace Prefix:	epm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The weighted average fair value of nonvested stock options and incentive warrants for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

No definition available.

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	epm_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsNonvestedWeightedAverageGrantDateFairValueRollForward
Namespace Prefix:	epm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The number of Stock Options and Incentive Warrants that vested during the reporting period.

No definition available.

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsVestedInPeriod
Namespace Prefix:	epm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The total fair value as of the grant date of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

No definition available.

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsVestedInPeriodTotalGrantDateFairValue
Namespace Prefix:	epm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The weighted average fair value as of grant date pertaining to stock options or incentive warrants for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

No definition available.

Name:	epm_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAndIncentiveWarrantsVestedInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	epm_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.