<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>81</ContextCount>
  <ElementCount>204</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>17</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>3</UnitCount>
  <MyReports>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - Condensed Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/CondensedBalanceSheets</Role>
      <ShortName>Condensed Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - Condensed Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/CondensedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - Condensed Statements Of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/CondensedStatementsOfComprehensiveIncomeLoss</Role>
      <ShortName>Condensed Statements Of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00300 - Statement - Condensed Statements Of Changes In Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/CondensedStatementsOfChangesInStockholdersEquity</Role>
      <ShortName>Condensed Statements Of Changes In Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00400 - Statement - Condensed Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/CondensedStatementsOfCashFlows</Role>
      <ShortName>Condensed Statements Of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureBasisOfPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureInvestments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/Inventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>20101 - Disclosure - Basis of Presentation (Policy)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/BasisofPresentationPolicy</Role>
      <ShortName>Basis of Presentation (Policy)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>30201 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureInvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureInvestments</ParentRole>
      <Position>12</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>30301 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureFairValueMeasurements</ParentRole>
      <Position>13</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>30401 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/InventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/Inventories</ParentRole>
      <Position>14</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Basis of Presentation (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureBasisofPresentationNarrativeDetails</Role>
      <ShortName>Basis of Presentation (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/BasisofPresentationPolicy</ParentRole>
      <Position>15</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Investments (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureInvestmentsNarrativeDetails</Role>
      <ShortName>Investments (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureInvestmentsTables</ParentRole>
      <Position>16</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>40202 - Disclosure - Investments (Cost And Estimated Fair Value Of Investments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureInvestmentsCostAndEstimatedFairValueOfInvestmentsDetails</Role>
      <ShortName>Investments (Cost And Estimated Fair Value Of Investments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureInvestmentsTables</ParentRole>
      <Position>17</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Fair Value Measurements (Fair Value Measurements On A Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/DisclosureFairValueMeasurementsFairValueMeasurementsOnRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements (Fair Value Measurements On A Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureFairValueMeasurementsTables</ParentRole>
      <Position>18</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>40303 - Disclosure - Fair Value Measurements (Fair Value Assets Measured on Recurring Basis Unobservable Inputs Reconciliation) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/FairValueMeasurementsFairValueAssetsMeasuredonRecurringBasisUnobservableInputsReconciliationDetails</Role>
      <ShortName>Fair Value Measurements (Fair Value Assets Measured on Recurring Basis Unobservable Inputs Reconciliation) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/DisclosureFairValueMeasurementsTables</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="else-20200630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.electro-sensors.com/role/InventoriesDetails</Role>
      <ShortName>Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.electro-sensors.com/role/InventoriesTables</ParentRole>
      <Position>20</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="else-20200630.htm">else-20200630.htm</File>
    <File>else-20200630.xsd</File>
    <File>else-20200630_cal.xml</File>
    <File>else-20200630_def.xml</File>
    <File>else-20200630_lab.xml</File>
    <File>else-20200630_pre.xml</File>
    <File>ex311_1.htm</File>
    <File>ex321_2.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
