<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.10.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>270</ContextCount>
  <ElementCount>343</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>85</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1002000 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002001 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003000 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ConsolidatedStatementsOfOperationsUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004000 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) Statement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ConsolidatedStatementsOfChangesInEquityUnauditedStatement</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) Statement</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Organization, Basis of Presentation and New Accounting Standards</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandards</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - Earnings per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/EarningsPerShare</Role>
      <ShortName>Earnings per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Fair Value of Assets and Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilities</Role>
      <ShortName>Fair Value of Assets and Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Loan Receivables Held for Sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/LoanReceivablesHeldForSale</Role>
      <ShortName>Loan Receivables Held for Sale</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - Accounts Receivable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/AccountsReceivable</Role>
      <ShortName>Accounts Receivable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - Property, Equipment and Software</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/PropertyEquipmentAndSoftware</Role>
      <ShortName>Property, Equipment and Software</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/Borrowings</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - Other Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OtherLiabilities</Role>
      <ShortName>Other Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2125100 - Disclosure - Noncontrolling Interests</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/NoncontrollingInterests</Role>
      <ShortName>Noncontrolling Interests</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2128100 - Disclosure - Share-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensation</Role>
      <ShortName>Share-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2131100 - Disclosure - Taxation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/Taxation</Role>
      <ShortName>Taxation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2134100 - Disclosure - Commitments, Contingencies and Guarantees</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/CommitmentsContingenciesAndGuarantees</Role>
      <ShortName>Commitments, Contingencies and Guarantees</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2137100 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/RelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2140100 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/SegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2143100 - Disclosure - Variable Interest Entities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntities</Role>
      <ShortName>Variable Interest Entities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2146100 - Disclosure - Temporary Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/TemporaryEquity</Role>
      <ShortName>Temporary Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2147100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2201201 - Disclosure - Organization, Basis of Presentation and New Accounting Standards (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsPolicies</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandards</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2301302 - Disclosure - Organization, Basis of Presentation and New Accounting Standards (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsTables</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandards</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - Earnings per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/EarningsPerShare</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Fair Value of Assets and Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesTables</Role>
      <ShortName>Fair Value of Assets and Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/FairValueOfAssetsAndLiabilities</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Loan Receivables Held for Sale (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/LoanReceivablesHeldForSaleTables</Role>
      <ShortName>Loan Receivables Held for Sale (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/LoanReceivablesHeldForSale</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2313301 - Disclosure - Accounts Receivable (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/AccountsReceivableTables</Role>
      <ShortName>Accounts Receivable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/AccountsReceivable</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - Property, Equipment and Software (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/PropertyEquipmentAndSoftwareTables</Role>
      <ShortName>Property, Equipment and Software (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/PropertyEquipmentAndSoftware</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/BorrowingsTables</Role>
      <ShortName>Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/Borrowings</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2322301 - Disclosure - Other Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OtherLiabilitiesTables</Role>
      <ShortName>Other Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/OtherLiabilities</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2328301 - Disclosure - Share-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationTables</Role>
      <ShortName>Share-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/ShareBasedCompensation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2334301 - Disclosure - Commitments, Contingencies and Guarantees (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/CommitmentsContingenciesAndGuaranteesTables</Role>
      <ShortName>Commitments, Contingencies and Guarantees (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/CommitmentsContingenciesAndGuarantees</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2337301 - Disclosure - Related Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/RelatedPartyTransactionsTables</Role>
      <ShortName>Related Party Transactions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/RelatedPartyTransactions</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2343301 - Disclosure - Variable Interest Entities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntitiesTables</Role>
      <ShortName>Variable Interest Entities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.greensky.com/role/VariableInterestEntities</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2401403 - Disclosure - Organization, Basis of Presentation and New Accounting Standards - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsNarrativeDetails</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2401404 - Disclosure - Organization, Basis of Presentation and New Accounting Standards - Cash and restricted cash (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsCashAndRestrictedCashDetails</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards - Cash and restricted cash (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2401405 - Disclosure - Organization, Basis of Presentation and New Accounting Standards - Revenue disaggregated by type of service (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OrganizationBasisOfPresentationAndNewAccountingStandardsRevenueDisaggregatedByTypeOfServiceDetails</Role>
      <ShortName>Organization, Basis of Presentation and New Accounting Standards - Revenue disaggregated by type of service (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - Earnings per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/EarningsPerShareDetails</Role>
      <ShortName>Earnings per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/EarningsPerShareTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Fair Value of Assets and Liabilities - Charged-Off Receivable transfers (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesChargedOffReceivableTransfersDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Charged-Off Receivable transfers (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Fair Value of Assets and Liabilities - Carrying amounts and estimated fair values of assets and liabilities measured at fair value on a recurring or nonrecurring basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesCarryingAmountsAndEstimatedFairValuesOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringOrNonrecurringBasisDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Carrying amounts and estimated fair values of assets and liabilities measured at fair value on a recurring or nonrecurring basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2407404 - Disclosure - Fair Value of Assets and Liabilities - (Increases)/decreases in fair value and locations related to liabilities measured at fair value on a recurring basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesIncreasesDecreasesInFairValueAndLocationsRelatedToLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - (Increases)/decreases in fair value and locations related to liabilities measured at fair value on a recurring basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2407405 - Disclosure - Fair Value of Assets and Liabilities - Reconciliation of the beginning and ending fair value measurements of FCR Liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesReconciliationOfBeginningAndEndingFairValueMeasurementsOfFcrLiabilityDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Reconciliation of the beginning and ending fair value measurements of FCR Liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2407406 - Disclosure - Fair Value of Assets and Liabilities - Significant unobservable inputs used to value Level 3 FCR liability (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesSignificantUnobservableInputsUsedToValueLevel3FcrLiabilityDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Significant unobservable inputs used to value Level 3 FCR liability (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2407407 - Disclosure - Fair Value of Assets and Liabilities - Impact on the fair value of liabilities assuming hypothetical changes in certain inputs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesImpactOnFairValueOfLiabilitiesAssumingHypotheticalChangesInCertainInputsDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Impact on the fair value of liabilities assuming hypothetical changes in certain inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2407408 - Disclosure - Fair Value of Assets and Liabilities - Additional information (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesAdditionalInformationNarrativeDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Additional information (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2407409 - Disclosure - Fair Value of Assets and Liabilities - Servicing liabilities and unobservable inputs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/FairValueOfAssetsAndLiabilitiesServicingLiabilitiesAndUnobservableInputsDetails</Role>
      <ShortName>Fair Value of Assets and Liabilities - Servicing liabilities and unobservable inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Loan Receivables Held for Sale - Activity in the balance of loan receivables held for sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/LoanReceivablesHeldForSaleActivityInBalanceOfLoanReceivablesHeldForSaleDetails</Role>
      <ShortName>Loan Receivables Held for Sale - Activity in the balance of loan receivables held for sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - Loan Receivables Held for Sale - Activities associated with loan receivable sales and servicing activities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/LoanReceivablesHeldForSaleActivitiesAssociatedWithLoanReceivableSalesAndServicingActivitiesDetails</Role>
      <ShortName>Loan Receivables Held for Sale - Activities associated with loan receivable sales and servicing activities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Loan Receivables Held for Sale - Principal balances of sold loan receivables (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/LoanReceivablesHeldForSalePrincipalBalancesOfSoldLoanReceivablesDetails</Role>
      <ShortName>Loan Receivables Held for Sale - Principal balances of sold loan receivables (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2413402 - Disclosure - Accounts Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/AccountsReceivableDetails</Role>
      <ShortName>Accounts Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/AccountsReceivableTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - Property, Equipment and Software (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/PropertyEquipmentAndSoftwareDetails</Role>
      <ShortName>Property, Equipment and Software (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/PropertyEquipmentAndSoftwareTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Borrowings - Credit Agreement (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/BorrowingsCreditAgreementDetails</Role>
      <ShortName>Borrowings - Credit Agreement (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2419403 - Disclosure - Borrowings - Schedule of term loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/BorrowingsScheduleOfTermLoansDetails</Role>
      <ShortName>Borrowings - Schedule of term loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2419404 - Disclosure - Borrowings - Credit Facility (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/BorrowingsCreditFacilityNarrativeDetails</Role>
      <ShortName>Borrowings - Credit Facility (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2422402 - Disclosure - Other Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/OtherLiabilitiesDetails</Role>
      <ShortName>Other Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/OtherLiabilitiesTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2425401 - Disclosure - Noncontrolling Interests (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/NoncontrollingInterestsDetails</Role>
      <ShortName>Noncontrolling Interests (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/NoncontrollingInterests</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2428402 - Disclosure - Share-Based Compensation - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationNarrativeDetails</Role>
      <ShortName>Share-Based Compensation - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2428403 - Disclosure - Share-Based Compensation - Class A Common Stock Options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationClassCommonStockOptionsDetails</Role>
      <ShortName>Share-Based Compensation - Class A Common Stock Options (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2428404 - Disclosure - Share-Based Compensation - Intrinsic Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationIntrinsicValueDetails</Role>
      <ShortName>Share-Based Compensation - Intrinsic Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2428405 - Disclosure - Share-Based Compensation - Profits Interests (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationProfitsInterestsDetails</Role>
      <ShortName>Share-Based Compensation - Profits Interests (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2428406 - Disclosure - Share-Based Compensation - Unvested HoldCo Units and Class A Common Stock Awards(Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/ShareBasedCompensationUnvestedHoldcoUnitsAndClassCommonStockAwardsdetails</Role>
      <ShortName>Share-Based Compensation - Unvested HoldCo Units and Class A Common Stock Awards(Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2431401 - Disclosure - Taxation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/TaxationDetails</Role>
      <ShortName>Taxation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/Taxation</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2434402 - Disclosure - Commitments, Contingencies and Guarantees - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/CommitmentsContingenciesAndGuaranteesNarrativeDetails</Role>
      <ShortName>Commitments, Contingencies and Guarantees - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2434403 - Disclosure - Commitments, Contingencies and Guarantees - Future Minimum Lease Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/CommitmentsContingenciesAndGuaranteesFutureMinimumLeasePaymentsDetails</Role>
      <ShortName>Commitments, Contingencies and Guarantees - Future Minimum Lease Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2437402 - Disclosure - Related Party Transactions - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/RelatedPartyTransactionsNarrativeDetails</Role>
      <ShortName>Related Party Transactions - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2437403 - Disclosure - Related Party Transactions - Schedule of Related Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/RelatedPartyTransactionsScheduleOfRelatedPartyTransactionsDetails</Role>
      <ShortName>Related Party Transactions - Schedule of Related Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2440401 - Disclosure - Segment Reporting (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/SegmentReportingDetails</Role>
      <ShortName>Segment Reporting (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/SegmentReporting</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2443402 - Disclosure - Variable Interest Entities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntitiesDetails</Role>
      <ShortName>Variable Interest Entities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/VariableInterestEntitiesTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2443403 - Disclosure - Variable Interest Entities - Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntitiesBalanceSheetDetails</Role>
      <ShortName>Variable Interest Entities - Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2443404 - Disclosure - Variable Interest Entities - Statement of Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntitiesStatementOfOperationsDetails</Role>
      <ShortName>Variable Interest Entities - Statement of Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>2443405 - Disclosure - Variable Interest Entities - Statement of Cash Flow (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/VariableInterestEntitiesStatementOfCashFlowDetails</Role>
      <ShortName>Variable Interest Entities - Statement of Cash Flow (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>2446401 - Disclosure - Temporary Equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.greensky.com/role/TemporaryEquityDetails</Role>
      <ShortName>Temporary Equity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.greensky.com/role/TemporaryEquity</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="gsky-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9999.htm</HtmlFileName>
      <LongName>Uncategorized Items - gsky-20180630.xml</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/role/uncategorizedFacts</Role>
      <ShortName>Uncategorized Items - gsky-20180630.xml</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>gsky-20180630.xml</File>
    <File>gsky-20180630.xsd</File>
    <File>gsky-20180630_cal.xml</File>
    <File>gsky-20180630_def.xml</File>
    <File>gsky-20180630_lab.xml</File>
    <File>gsky-20180630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2018-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2018-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
