<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.3.1.900</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>17</ContextCount>
  <ElementCount>87</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>15</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>01001 - Document - Document and Entity Information {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/DocumentAndEntityInformation1</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory></MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>01002 - Document - Risk/Return Summary (Thompson LargeCap Fund) {Unlabeled}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRSummary2</Role>
      <ShortName>Risk/Return Summary (Thompson LargeCap Fund)</ShortName>
      <MenuCategory></MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>01018 - Disclosure - Risk/Return Detail Data {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRDetailData20</Role>
      <ShortName>Risk/Return Detail Data</ShortName>
      <MenuCategory></MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>01019 - Document - Risk/Return Summary (Thompson MidCap Fund) {Unlabeled}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRSummary8</Role>
      <ShortName>Risk/Return Summary (Thompson MidCap Fund)</ShortName>
      <MenuCategory></MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>01020 - Disclosure - Risk/Return Detail Data (Thompson MidCap Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRDetailData21</Role>
      <ShortName>Risk/Return Detail Data (Thompson MidCap Fund)</ShortName>
      <MenuCategory></MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>true</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>01021 - Document - Risk/Return Summary (Thompson Bond Fund) {Unlabeled}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRSummary14</Role>
      <ShortName>Risk/Return Summary (Thompson Bond Fund)</ShortName>
      <MenuCategory></MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>01022 - Disclosure - Risk/Return Detail Data (Thompson Bond Fund) {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.thompsonim.com/role/RRDetailData22</Role>
      <ShortName>Risk/Return Detail Data (Thompson Bond Fund)</ShortName>
      <MenuCategory></MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="ck0000795264-20160328.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.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>
      <MenuCategory></MenuCategory>
      <Position>8</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>ck0000795264-20160328.xml</File>
    <File>ck0000795264-20160328.xsd</File>
    <File>ck0000795264-20160328_cal.xml</File>
    <File>ck0000795264-20160328_def.xml</File>
    <File>ck0000795264-20160328_lab.xml</File>
    <File>ck0000795264-20160328_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>BarChart1.png</File>
    <File>BarChart2.png</File>
    <File>BarChart3.png</File>
  </SupplementalFiles>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
