2.4.0.840204 - Disclosure - Acquisitions (Schedule of Revenues and Lease Operating Expenses Attributable to the ST 41 Interests and the Hilcorp Properties) (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$Duration_4_1_2013_To_6_30_2013_us-gaap_BusinessAcquisitionAxis_epl_SouthTimbalierAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2013-04-01T00:00:002013-06-30T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$Duration_4_1_2012_To_6_30_2012_us-gaap_BusinessAcquisitionAxis_epl_SouthTimbalierAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2012-04-01T00:00:002012-06-30T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$Duration_1_1_2013_To_6_30_2013_us-gaap_BusinessAcquisitionAxis_epl_SouthTimbalierAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2013-01-01T00:00:002013-06-30T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$Duration_1_1_2012_To_6_30_2012_us-gaap_BusinessAcquisitionAxis_epl_SouthTimbalierAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2012-01-01T00:00:002012-06-30T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse1false USDtruefalse$Duration_4_1_2013_To_6_30_2013_us-gaap_BusinessAcquisitionAxis_epl_HilcorpPropertiesAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseHilcorp Properties Acquisition [Member]us-gaap_BusinessAcquisitionAxisxbrldihttp://xbrl.org/2006/xbrldiepl_HilcorpPropertiesAcquisitionMemberus-gaap_BusinessAcquisitionAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Hilcorp Properties Acquisition [Member]2true 3us-gaap_BusinessAcquisitionLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Business Acquisition [Line Items]3false 4epl_RevenueAttributableToAcquiredPropertiesepl_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse4814800048148USD$falsetruefalse2falsefalsefalse00falsefalsefalse3truefalsefalse103669000103669USD$falsetruefalse4falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryRevenue attributable to acquired properties.No definition available.false2Revenue4false 4epl_LeaseOperatingExpensesAttributableToAcquiredPropertiesepl_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse2006000020060USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse3913100039131USD$falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryLease operating expenses attributable to acquired properties.No definition available.false2Lease operating expenses5false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse3false USDtruefalse$Duration_4_1_2013_To_6_30_2013_us-gaap_BusinessAcquisitionAxis_epl_SouthTimbalierAcquisitionMemberhttp://www.sec.gov/CIK0000750199duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseSouth Timbalier Acquisition [Member]us-gaap_BusinessAcquisitionAxisxbrldihttp://xbrl.org/2006/xbrldiepl_SouthTimbalierAcquisitionMemberus-gaap_BusinessAcquisitionAxisexplicitMemberUnit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0South Timbalier Acquisition [Member]6true 3us-gaap_BusinessAcquisitionLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Business Acquisition [Line Items]7false 4epl_RevenueAttributableToAcquiredPropertiesepl_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse28310002831USD$falsefalsefalse2truefalsefalse19370001937USD$falsefalsefalse3truefalsefalse59300005930USD$falsefalsefalse4truefalsefalse19370001937USD$falsefalsefalsexbrli:monetaryItemTypemonetaryRevenue attributable to acquired properties.No definition available.false2Revenue8false 4epl_LeaseOperatingExpensesAttributableToAcquiredPropertiesepl_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse426000426USD$falsetruefalse2truefalsefalse292000292USD$falsetruefalse3truefalsefalse10340001034USD$falsetruefalse4truefalsefalse292000292USD$falsetruefalsexbrli:monetaryItemTypemonetaryLease operating expenses attributable to acquired properties.No definition available.false2Lease operating expensesfalseAcquisitions (Schedule of Revenues and Lease Operating Expenses Attributable to the ST 41 Interests and the Hilcorp Properties) (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://eplweb.com/role/DisclosureAcquisitionsScheduleOfRevenuesAndLeaseOperatingExpensesAttributableToSt41InterestsAndHilcorpPropertiesDetails48