<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Version>2.4.0.8</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>39</ContextCount>
  <ElementCount>160</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>9</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>001 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>002 - Statement - BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/BalanceSheets</Role>
      <ShortName>BALANCE SHEETS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>003 - Statement - BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/BalanceSheetsParenthetical</Role>
      <ShortName>BALANCE SHEETS (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>004 - Statement - STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/StatementsOfOperations</Role>
      <ShortName>STATEMENTS OF OPERATIONS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>005 - Statement - STATEMENTS OF CHANGES IN MEMBERS' CAPITAL</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/StatementsOfChangesInMembersCapital</Role>
      <ShortName>STATEMENTS OF CHANGES IN MEMBERS' CAPITAL</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>006 - Statement - STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/StatementsOfCashFlows</Role>
      <ShortName>STATEMENTS OF CASH FLOWS</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>101 - Disclosure - Organization and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OrganizationAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>102 - Disclosure - Derivative Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/DerivativeInstruments</Role>
      <ShortName>Derivative Instruments</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>103 - Disclosure - Oil and Gas Properties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OilAndGasProperties</Role>
      <ShortName>Oil and Gas Properties</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>104 - Disclosure - Related Parties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/RelatedParties</Role>
      <ShortName>Related Parties</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>105 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>106 - Disclosure - Information about Oil and Gas Producing Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivities</Role>
      <ShortName>Information about Oil and Gas Producing Activities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>201 - Disclosure - Organization and Summary of Significant Accounting Policies (Policy)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OrganizationAndSummaryOfSignificantAccountingPoliciesPolicy</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Policy)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>301 - Disclosure - Organization and Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OrganizationAndSummaryOfSignificantAccountingPoliciesTables</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>303 - Disclosure - Oil And Gas Properties (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OilAndGasPropertiesTables</Role>
      <ShortName>Oil And Gas Properties (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>306 - Disclosure - Information about Oil and Gas Producing Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesTables</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Organization and Summary of Significant Accounting Policies (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OrganizationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Narrative) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>40102 - Disclosure - Organization and Summary of Significant Accounting Policies (Schedule of Changes in Asset Retirement Obligations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OrganizationAndSummaryOfSignificantAccountingPoliciesScheduleOfChangesInAssetRetirementObligationsDetails</Role>
      <ShortName>Organization and Summary of Significant Accounting Policies (Schedule of Changes in Asset Retirement Obligations) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/DerivativeInstrumentsDetails</Role>
      <ShortName>Derivative Instruments (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Oil and Gas Properties (Schedule of Net Changes in Unproved Oil and Gas Properties) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OilAndGasPropertiesScheduleOfNetChangesInUnprovedOilAndGasPropertiesDetails</Role>
      <ShortName>Oil and Gas Properties (Schedule of Net Changes in Unproved Oil and Gas Properties) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>40302 - Disclosure - Oil and Gas Properties (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/OilAndGasPropertiesNarrativeDetails</Role>
      <ShortName>Oil and Gas Properties (Narrative) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Related Parties (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/RelatedPartiesDetails</Role>
      <ShortName>Related Parties (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/CommitmentsAndContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Information about Oil and Gas Producing Activities (Schedule of Capitalized Costs Relating to Oil and Gas Producing Activities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesScheduleOfCapitalizedCostsRelatingToOilAndGasProducingActivitiesDetails</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Schedule of Capitalized Costs Relating to Oil and Gas Producing Activities) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>40602 - Disclosure - Information about Oil and Gas Producing Activities (Schedule of Costs Incurred in Oil and Gas Property Acquisition, Exploration, and Development) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesScheduleOfCostsIncurredInOilAndGasPropertyAcquisitionExplorationAndDevelopmentDetails</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Schedule of Costs Incurred in Oil and Gas Property Acquisition, Exploration, and Development) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>40603 - Disclosure - Information about Oil and Gas Producing Activities (Schedule of Reserve Quantity Information) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesScheduleOfReserveQuantityInformationDetails</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Schedule of Reserve Quantity Information) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>40604 - Disclosure - Information about Oil and Gas Producing Activities (Schedule of Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesScheduleOfStandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesDetails</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Schedule of Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>40605 - Disclosure - Information about Oil and Gas Producing Activities (Schedule of Changes in the Standardized Measure for Discounted Cash Flows) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ridgewoodenergyu.com/role/InformationAboutOilAndGasProducingActivitiesScheduleOfChangesInStandardizedMeasureForDiscountedCashFlowsDetails</Role>
      <ShortName>Information about Oil and Gas Producing Activities (Schedule of Changes in the Standardized Measure for Discounted Cash Flows) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element cik1377178_ValueOfCapitalExpendituresForOilAndGasPropertiesOwedToOperators had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">'Monetary' elements on report '40101 - Disclosure - Organization and Summary of Significant Accounting Policies (Narrative) (Details)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 002 - Statement - BALANCE SHEETS</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 003 - Statement - BALANCE SHEETS (Parenthetical)</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 004 - Statement - STATEMENTS OF OPERATIONS</Log>
    <Log type="Info">Process Flow-Through: 005 - Statement - STATEMENTS OF CHANGES IN MEMBERS' CAPITAL</Log>
    <Log type="Info">Process Flow-Through: 006 - Statement - STATEMENTS OF CASH FLOWS</Log>
  </Logs>
  <InputFiles>
    <File>cik1377178-20131231.xml</File>
    <File>cik1377178-20131231.xsd</File>
    <File>cik1377178-20131231_cal.xml</File>
    <File>cik1377178-20131231_def.xml</File>
    <File>cik1377178-20131231_lab.xml</File>
    <File>cik1377178-20131231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
