<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>2.4.0.6</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>12</ContextCount>
  <ElementCount>114</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>0</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>101 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DocumentDocumentandEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>103 - Statement - Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/StatementOfFinancialPositionClassified-RealEstateOperations</Role>
      <ShortName>Balance Sheets (Unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>104 - Statement - Balance Sheets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/StatementOfFinancialPositionClassified-RealEstateOperationsParenthetical</Role>
      <ShortName>Balance Sheets (Unaudited) (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>105 - Statement - Statements of Operations (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/StatementOfIncomeRealEstateExcludingREITs</Role>
      <ShortName>Statements of Operations (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>106 - Statement - Statements of Operations (unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/StatementOfIncomeRealEstateExcludingREITsParenthetical</Role>
      <ShortName>Statements of Operations (unaudited) (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>107 - Statement - Statements of Cash Flows (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/StatementOfCashFlowsIndirectRealEstate</Role>
      <ShortName>Statements of Cash Flows (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>108 - Disclosure - Organization and Basis of Accounting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsOrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock</Role>
      <ShortName>Organization and Basis of Accounting</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>109 - Disclosure - Discontinued Operations and Investment Property Held for Sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsDisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock</Role>
      <ShortName>Discontinued Operations and Investment Property Held for Sale</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>110 - Disclosure - Transactions with Affiliates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsRelatedPartyTransactionsDisclosureTextBlock</Role>
      <ShortName>Transactions with Affiliates</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>111 - Disclosure - Investment Properties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsRealEstateDisclosureTextBlock</Role>
      <ShortName>Investment Properties</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>112 - Disclosure - Rental Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsOperatingLeasesOfLessorDisclosureTextBlock</Role>
      <ShortName>Rental Income</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>113 - Disclosure - Litigation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsLegalMattersAndContingenciesTextBlock</Role>
      <ShortName>Litigation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>114 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsSubsequentEventsTextBlock</Role>
      <ShortName>Subsequent Events</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>115 - Disclosure - Investment Properties (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/NotesToFinancialStatementsRealEstateDisclosureTextBlockTables</Role>
      <ShortName>Investment Properties (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>116 - Disclosure - Organization and Basis of Accounting (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureOrganizationAndBasisOfAccounting</Role>
      <ShortName>Organization and Basis of Accounting (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>117 - Disclosure - Discontinued Operations and Investment Property Held for Sale (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureDiscontinuedOperationsAndInvestmentPropertyHeldForSale</Role>
      <ShortName>Discontinued Operations and Investment Property Held for Sale (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>118 - Disclosure - Transactions with Affiliates (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureTransactionsWithAffiliates</Role>
      <ShortName>Transactions with Affiliates (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>119 - Disclosure - Investment Properties (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureInvestmentProperties</Role>
      <ShortName>Investment Properties (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>120 - Disclosure - Reconciliation of Investment Properties Owned (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureReconciliationOfInvestmentPropertiesOwned</Role>
      <ShortName>Reconciliation of Investment Properties Owned (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>121 - Disclosure - Rental Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureRentalIncome</Role>
      <ShortName>Rental Income (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>122 - Disclosure - Litigation (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://imetrix.edgar-online.com/taxonomy/role/DisclosureLitigation</Role>
      <ShortName>Litigation (Detail)</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">'Monetary' elements on report '122 - Disclosure - Litigation (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 103 - Statement - Balance Sheets (Unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Sep. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2010'</Log>
    <Log type="Info">Process Flow-Through: 104 - Statement - Balance Sheets (Unaudited) (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 105 - Statement - Statements of Operations (unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column '1 Months Ended
Sep. 19, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '12 Months Ended
Dec. 31, 2011'</Log>
    <Log type="Info">Process Flow-Through: 106 - Statement - Statements of Operations (unaudited) (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 107 - Statement - Statements of Cash Flows (unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2012'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '3 Months Ended
Sep. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column '12 Months Ended
Dec. 31, 2011'</Log>
  </Logs>
  <InputFiles>
    <File>ck0000853496-20120930.xml</File>
    <File>ck0000853496-20120930.xsd</File>
    <File>ck0000853496-20120930_cal.xml</File>
    <File>ck0000853496-20120930_def.xml</File>
    <File>ck0000853496-20120930_lab.xml</File>
    <File>ck0000853496-20120930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
