Results of Operations, Income Tax Expense (Benefit)

No definition available.

Name:	end_ResultsOfOperationsIncomeTaxExpenseBenefit
Namespace Prefix:	end_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Section 35

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

+ Details

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

- Definition

Aggregate revenue during the period related to oil and gas business activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 23

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62246-109447

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_OilAndGasRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

+ References

No definition available.

+ Details

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

- Definition

Depreciation, depletion and amortization, and valuation provisions (impairments) related to oil and gas producing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 23

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447

+ Details

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

- Details

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

- Definition

The results of operations for oil and gas producing activities, excluding corporate overhead and interest costs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62299-109447

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 23

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447

+ Details

Name:	us-gaap_ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_StatementGeographicalAxis=country_GB
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Supplemental Oil and Gas Disclosures (Results of Ops) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Results Of Operations For Oil And Gas Producing Activities By Geographic Area [Line Items]
Revenues	$ 90,567us-gaap_OilAndGasRevenue	$ 86,445us-gaap_OilAndGasRevenue	$ 44,857us-gaap_OilAndGasRevenue	$ 94,163us-gaap_OilAndGasRevenue	$ 116,926us-gaap_OilAndGasRevenue	$ 36,901us-gaap_OilAndGasRevenue	$ 126,165us-gaap_OilAndGasRevenue	$ 57,672us-gaap_OilAndGasRevenue	$ 316,032us-gaap_OilAndGasRevenue	$ 337,664us-gaap_OilAndGasRevenue	$ 219,058us-gaap_OilAndGasRevenue
Production expenses	542,897us-gaap_OperatingCostsAndExpenses	338,512us-gaap_OperatingCostsAndExpenses	44,338us-gaap_OperatingCostsAndExpenses	76,987us-gaap_OperatingCostsAndExpenses	87,922us-gaap_OperatingCostsAndExpenses	44,899us-gaap_OperatingCostsAndExpenses	94,908us-gaap_OperatingCostsAndExpenses	49,453us-gaap_OperatingCostsAndExpenses	86,990us-gaap_OperatingCostsAndExpenses	105,444us-gaap_OperatingCostsAndExpenses	58,536us-gaap_OperatingCostsAndExpenses
DD&A									174,168	140,981	64,387
Impairment of oil and gas properties						6,000us-gaap_ImpairmentOfOilAndGasProperties		3,500us-gaap_ImpairmentOfOilAndGasProperties	476,721us-gaap_ImpairmentOfOilAndGasProperties	9,566us-gaap_ImpairmentOfOilAndGasProperties	53,072us-gaap_ImpairmentOfOilAndGasProperties
Income tax expense (benefit)									(242,336)	53,833	41,748
Results of activities									(179,511)	27,840	1,315
United Kingdom [Member]
Results Of Operations For Oil And Gas Producing Activities By Geographic Area [Line Items]
Revenues									309,303	329,296	207,181
Production expenses									82,504	98,045	51,568
DD&A									172,343	137,739	56,813
Impairment of oil and gas properties									405,159
Income tax expense (benefit)									(217,436)	57,977	61,256
Results of activities									(133,267)	35,535	37,544
United States [Member]
Results Of Operations For Oil And Gas Producing Activities By Geographic Area [Line Items]
Revenues									6,729	8,368	11,877
Production expenses									4,486	7,399	6,968
DD&A									1,825	3,242	7,574
Impairment of oil and gas properties									71,562	9,566	53,072
Income tax expense (benefit)									(24,900)	(4,144)	(19,508)
Results of activities									$ (46,244)	$ (7,695)	$ (36,229)