<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xml:lang="en-US"
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2020-01-31"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="fcfs-20201105.xsd" xlink:type="simple"/>
    <context id="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000840489</identifier>
        </entity>
        <period>
            <startDate>2020-11-05</startDate>
            <endDate>2020-11-05</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF80L2ZyYWc6OWFiMmUxNjNjOTliNGVjOGE1MTg2ZjgxOGI1NzFlOWYvdGFibGU6OWQ0NTA0OWVhMTQyNDc4NzgyNDIzMzY4MDg4NmEzMzMvdGFibGVyYW5nZTo5ZDQ1MDQ5ZWExNDI0Nzg3ODI0MjMzNjgwODg2YTMzM18yLTEtMS0xLTA_7d56516b-a7c8-434d-bb6d-a0d31708462a">0000840489</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF80L2ZyYWc6OWFiMmUxNjNjOTliNGVjOGE1MTg2ZjgxOGI1NzFlOWYvdGFibGU6OWQ0NTA0OWVhMTQyNDc4NzgyNDIzMzY4MDg4NmEzMzMvdGFibGVyYW5nZTo5ZDQ1MDQ5ZWExNDI0Nzg3ODI0MjMzNjgwODg2YTMzM18zLTEtMS0xLTA_26d4dd45-a9e1-4506-8367-9d79659acdbb">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNjA0_fe7b1f06-2ca0-4dfc-9cbb-1efce3711d03">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNzc_9139e7a4-d64b-4322-be21-0f60ecf8b25f">2020-11-05</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNjA5_849bed1d-a907-43d9-a9be-2fefe0f337c1">FIRSTCASH, INC.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6N2Y3NTkwZmM4YWM4NDBiN2EwY2E0OTE0MDU2YzQ5ZDUvdGFibGVyYW5nZTo3Zjc1OTBmYzhhYzg0MGI3YTBjYTQ5MTQwNTZjNDlkNV8wLTAtMS0xLTA_61714d58-5494-4d6a-bb8a-6eccceabe9c3">DE</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6N2Y3NTkwZmM4YWM4NDBiN2EwY2E0OTE0MDU2YzQ5ZDUvdGFibGVyYW5nZTo3Zjc1OTBmYzhhYzg0MGI3YTBjYTQ5MTQwNTZjNDlkNV8wLTEtMS0xLTA_d5ae91ad-6442-4d99-9b99-47a71b3c77ad">001-10960</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6N2Y3NTkwZmM4YWM4NDBiN2EwY2E0OTE0MDU2YzQ5ZDUvdGFibGVyYW5nZTo3Zjc1OTBmYzhhYzg0MGI3YTBjYTQ5MTQwNTZjNDlkNV8wLTItMS0xLTA_ea9a95e0-a362-4936-a5a9-e217bc855d42">75-2237318</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xMDk5NTExNjMxNTUy_4a8b236f-b6fa-4345-b1c8-aaf043da2e82">1600 West 7th Street</dei:EntityAddressAddressLine1>
    <dei:EntityAddressCityOrTown
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xMDk5NTExNjMxNTUz_255e3938-86a4-4091-9046-3a303e0f2a13">Fort Worth</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xMDk5NTExNjMxNTU1_4cac8daf-8047-455d-be03-f53b9aa06184">TX</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xMDk5NTExNjMxNTU3_2d011c78-4582-4ce7-bfe7-5e6a0e776256">76102</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNjA1_29a91fe8-d70a-4bee-a6e4-4ef3352c884d">817</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNjA2_6a4de141-e98d-4096-8690-2b585d7516bd">335-1100</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6MWUyNGEzZGMxODkzNDFjN2EzMDY3NGVmYzcyOTM1ZTgvdGFibGVyYW5nZToxZTI0YTNkYzE4OTM0MWM3YTMwNjc0ZWZjNzI5MzVlOF8wLTAtMS0xLTEyOQ_f13c48a2-f9fa-4176-bc1e-21e1fa6b4845">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6MWUyNGEzZGMxODkzNDFjN2EzMDY3NGVmYzcyOTM1ZTgvdGFibGVyYW5nZToxZTI0YTNkYzE4OTM0MWM3YTMwNjc0ZWZjNzI5MzVlOF8xLTAtMS0xLTEzMg_4c8d22ef-f851-489f-8130-bb0f44a7d67e">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6MWUyNGEzZGMxODkzNDFjN2EzMDY3NGVmYzcyOTM1ZTgvdGFibGVyYW5nZToxZTI0YTNkYzE4OTM0MWM3YTMwNjc0ZWZjNzI5MzVlOF8yLTAtMS0xLTEzNQ_b0b8b92d-e315-4ca9-8d61-343775ec6181">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6MWUyNGEzZGMxODkzNDFjN2EzMDY3NGVmYzcyOTM1ZTgvdGFibGVyYW5nZToxZTI0YTNkYzE4OTM0MWM3YTMwNjc0ZWZjNzI5MzVlOF8zLTAtMS0xLTEzOA_8976624f-7337-4d89-8810-c0ba9f60f66a">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6YTAxZmRjYWU2ZjRhNDkyMGE4MDJmZWFkZWUyMTQ3YmYvdGFibGVyYW5nZTphMDFmZGNhZTZmNGE0OTIwYTgwMmZlYWRlZTIxNDdiZl8xLTAtMS0xLTA_ddd05e9f-1bf9-4c5d-aef2-690d299590e1">Common Stock, par value $.01 per share</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6YTAxZmRjYWU2ZjRhNDkyMGE4MDJmZWFkZWUyMTQ3YmYvdGFibGVyYW5nZTphMDFmZGNhZTZmNGE0OTIwYTgwMmZlYWRlZTIxNDdiZl8xLTEtMS0xLTA_9724a27b-8c13-4a96-b000-506f51573bee">FCFS</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGFibGU6YTAxZmRjYWU2ZjRhNDkyMGE4MDJmZWFkZWUyMTQ3YmYvdGFibGVyYW5nZTphMDFmZGNhZTZmNGE0OTIwYTgwMmZlYWRlZTIxNDdiZl8xLTItMS0xLTA_83e16fba-00ed-4aae-9e9d-edce63710772">NASDAQ</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="ifc51e21fd4604724b896271ce6b54181_D20201105-20201105"
      id="id3VybDovL2RvY3MudjEvZG9jOjNlZDQyZDkwNWYyNTQyOTE5MWI3ODliODVlYzcxYzY4L3NlYzozZWQ0MmQ5MDVmMjU0MjkxOTFiNzg5Yjg1ZWM3MWM2OF8xL2ZyYWc6YTBhYjkwYzdjZjYzNDBkZDkxZTAxZGYwZDdjYWVlOTEvdGV4dHJlZ2lvbjphMGFiOTBjN2NmNjM0MGRkOTFlMDFkZjBkN2NhZWU5MV8xNjAz_dff209f6-5708-4252-b7e7-92a25e8f0125">false</dei:EntityEmergingGrowthCompany>
</xbrl>
