Represents the percentage of overriding royalty interest in product service purchased by the entity.

No definition available.

Name:	epm_LossContingenciesPercentageofOverridingRoyaltyInterestinProductServicePurchased
Namespace Prefix:	epm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of senior executives of the entity covered under employment agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	epm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the period of benefits, includes payment of base pay and certain medical and disability benefits, after the termination from employment.

+ References

No definition available.

+ Details

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Namespace Prefix:	epm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Related Party Transactions, Overriding Royalty Interest with Suspended Payments, Amount Previously Suspended

+ References

No definition available.

+ Details

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Namespace Prefix:	epm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Related Party Transactions, Percentage of Overriding Royalty Interest with Suspended Payments

+ References

No definition available.

+ Details

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Namespace Prefix:	epm_
Data Type:	num:percentItemType
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

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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=25496072&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=25496072&loc=d3e14557-108349

+ Details

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

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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Period Type:

- Details

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Namespace Prefix:
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- Details

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Commitments and Contingencies - Narrative (Details)	12 Months Ended
Commitments and Contingencies - Narrative (Details)	Jun. 30, 2015 USD ($) senior_executive	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Feb. 26, 2015 USD ($)	Jan. 26, 2015
Loss Contingencies [Line Items]
Overriding royalty interest in the Delhi Unit	4.8119%
Rent expense	$ 175,103	$ 174,229	$ 147,233
Employment Contracts
Loss Contingencies [Line Items]
Number of senior executives under agreement \| senior_executive	2
Total contingent obligations	$ 473,000
Minimum \| Employment Contracts
Loss Contingencies [Line Items]
Period of benefits to employee after termination	6 months
Maximum \| Employment Contracts
Loss Contingencies [Line Items]
Period of benefits to employee after termination	1 year
Denbury Resources, Inc
Loss Contingencies [Line Items]
Suspended overriding royalty revenue interest					2.89155%
Suspended overriding royalty interest, amount previously suspended				$ 712,000