<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>34</ContextCount>
  <ElementCount>30</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>14</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="faf-20260319.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstam.com/20260319/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="faf-20260319.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="faf-20260319.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>995443 - Disclosure - Award Timing Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure</Role>
      <ShortName>Award Timing Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="faf-20260319.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>995447 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>4</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="PRE 14A" isUsgaap="true" original="faf-20260319.htm">faf-20260319.htm</File>
    <File>faf-20260319.xsd</File>
  </InputFiles>
  <SupplementalFiles>
    <File>img183557730_0.jpg</File>
    <File>img183557730_1.jpg</File>
    <File>img183557730_10.jpg</File>
    <File>img183557730_11.jpg</File>
    <File>img183557730_12.jpg</File>
    <File>img183557730_13.jpg</File>
    <File>img183557730_14.jpg</File>
    <File>img183557730_15.jpg</File>
    <File>img183557730_16.gif</File>
    <File>img183557730_17.jpg</File>
    <File>img183557730_18.jpg</File>
    <File>img183557730_19.gif</File>
    <File>img183557730_2.jpg</File>
    <File>img183557730_20.jpg</File>
    <File>img183557730_21.jpg</File>
    <File>img183557730_22.jpg</File>
    <File>img183557730_23.jpg</File>
    <File>img183557730_24.jpg</File>
    <File>img183557730_25.jpg</File>
    <File>img183557730_26.jpg</File>
    <File>img183557730_27.jpg</File>
    <File>img183557730_28.jpg</File>
    <File>img183557730_29.jpg</File>
    <File>img183557730_3.gif</File>
    <File>img183557730_30.jpg</File>
    <File>img183557730_31.jpg</File>
    <File>img183557730_32.jpg</File>
    <File>img183557730_33.jpg</File>
    <File>img183557730_34.jpg</File>
    <File>img183557730_35.jpg</File>
    <File>img183557730_36.jpg</File>
    <File>img183557730_37.jpg</File>
    <File>img183557730_38.jpg</File>
    <File>img183557730_39.jpg</File>
    <File>img183557730_4.jpg</File>
    <File>img183557730_40.jpg</File>
    <File>img183557730_41.jpg</File>
    <File>img183557730_42.jpg</File>
    <File>img183557730_43.jpg</File>
    <File>img183557730_44.jpg</File>
    <File>img183557730_45.jpg</File>
    <File>img183557730_46.jpg</File>
    <File>img183557730_47.jpg</File>
    <File>img183557730_48.jpg</File>
    <File>img183557730_49.jpg</File>
    <File>img183557730_5.jpg</File>
    <File>img183557730_50.jpg</File>
    <File>img183557730_51.jpg</File>
    <File>img183557730_52.jpg</File>
    <File>img183557730_53.jpg</File>
    <File>img183557730_54.jpg</File>
    <File>img183557730_55.gif</File>
    <File>img183557730_56.gif</File>
    <File>img183557730_57.gif</File>
    <File>img183557730_58.jpg</File>
    <File>img183557730_59.gif</File>
    <File>img183557730_6.jpg</File>
    <File>img183557730_60.gif</File>
    <File>img183557730_61.jpg</File>
    <File>img183557730_62.jpg</File>
    <File>img183557730_63.jpg</File>
    <File>img183557730_64.jpg</File>
    <File>img183557730_65.jpg</File>
    <File>img183557730_66.jpg</File>
    <File>img183557730_7.jpg</File>
    <File>img183557730_8.jpg</File>
    <File>img183557730_9.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="5">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="81">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
