<?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>HtmlAndXml</ReportFormat>
  <ContextCount>32</ContextCount>
  <ElementCount>84</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>20</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000001 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <XmlFileName>R1.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>020000 - Document - Risk/Return Summary {Unlabeled} - Institutional Class Prospectus - MegaTrends Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentRiskReturnSummaryUnlabeledInstitutionalClassProspectusMegaTrendsFund</Role>
      <ShortName>Risk/Return Summary  - Institutional Class Prospectus - MegaTrends Fund</ShortName>
      <XmlFileName>R2.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>020006 - Disclosure - Risk/Return Detail Data {Elements} - Institutional Class Prospectus - MegaTrends Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DisclosureRiskReturnDetailDataElementsInstitutionalClassProspectusMegaTrendsFund</Role>
      <ShortName>Risk/Return Detail Data  - Institutional Class Prospectus - MegaTrends Fund</ShortName>
      <XmlFileName>R8.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>020007 - Document - Risk/Return Summary {Unlabeled} - Institutional Class Prospectus - Gold and Precious Metals Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentRiskReturnSummaryUnlabeledInstitutionalClassProspectusGoldandPreciousMetalsFund</Role>
      <ShortName>Risk/Return Summary  - Institutional Class Prospectus - Gold and Precious Metals Fund</ShortName>
      <XmlFileName>R9.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>020013 - Disclosure - Risk/Return Detail Data {Elements} - Institutional Class Prospectus - Gold and Precious Metals Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DisclosureRiskReturnDetailDataElementsInstitutionalClassProspectusGoldandPreciousMetalsFund</Role>
      <ShortName>Risk/Return Detail Data  - Institutional Class Prospectus - Gold and Precious Metals Fund</ShortName>
      <XmlFileName>R15.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>020014 - Document - Risk/Return Summary {Unlabeled} - Institutional Class Prospectus - World Precious Minerals Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentRiskReturnSummaryUnlabeledInstitutionalClassProspectusWorldPreciousMineralsFund</Role>
      <ShortName>Risk/Return Summary  - Institutional Class Prospectus - World Precious Minerals Fund</ShortName>
      <XmlFileName>R16.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>020020 - Disclosure - Risk/Return Detail Data {Elements} - Institutional Class Prospectus - World Precious Minerals Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DisclosureRiskReturnDetailDataElementsInstitutionalClassProspectusWorldPreciousMineralsFund</Role>
      <ShortName>Risk/Return Detail Data  - Institutional Class Prospectus - World Precious Minerals Fund</ShortName>
      <XmlFileName>R22.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>020021 - Document - Risk/Return Summary {Unlabeled} - Institutional Class Prospectus - Global Resources Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentRiskReturnSummaryUnlabeledInstitutionalClassProspectusGlobalResourcesFund</Role>
      <ShortName>Risk/Return Summary  - Institutional Class Prospectus - Global Resources Fund</ShortName>
      <XmlFileName>R23.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>020027 - Disclosure - Risk/Return Detail Data {Elements} - Institutional Class Prospectus - Global Resources Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DisclosureRiskReturnDetailDataElementsInstitutionalClassProspectusGlobalResourcesFund</Role>
      <ShortName>Risk/Return Detail Data  - Institutional Class Prospectus - Global Resources Fund</ShortName>
      <XmlFileName>R29.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>020028 - Document - Risk/Return Summary {Unlabeled} - Institutional Class Prospectus - Emerging Europe Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DocumentRiskReturnSummaryUnlabeledInstitutionalClassProspectusEmergingEuropeFund</Role>
      <ShortName>Risk/Return Summary  - Institutional Class Prospectus - Emerging Europe Fund</ShortName>
      <XmlFileName>R30.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>020034 - Disclosure - Risk/Return Detail Data {Elements} - Institutional Class Prospectus - Emerging Europe Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://usglobal.com/20130809/role/DisclosureRiskReturnDetailDataElementsInstitutionalClassProspectusEmergingEuropeFund</Role>
      <ShortName>Risk/Return Detail Data  - Institutional Class Prospectus - Emerging Europe Fund</ShortName>
      <XmlFileName>R36.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>040000 - Disclosure - Risk/Return Detail Data {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/RiskReturnDetailData</Role>
      <ShortName>Risk/Return Detail Data</ShortName>
      <XmlFileName>R37.xml</XmlFileName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs />
  <InputFiles>
    <File>ck0000101507-20130809.xml</File>
    <File>ck0000101507-20130809.xsd</File>
    <File>ck0000101507-20130809_cal.xml</File>
    <File>ck0000101507-20130809_def.xml</File>
    <File>ck0000101507-20130809_lab.xml</File>
    <File>ck0000101507-20130809_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>BarChart1.jpg</File>
    <File>BarChart2.jpg</File>
    <File>BarChart3.jpg</File>
    <File>BarChart4.jpg</File>
    <File>BarChart5.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
