<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.19.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>266</ContextCount>
  <ElementCount>329</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>49</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000100 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>010000 - Statement - Unaudited Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedBalanceSheets</Role>
      <ShortName>Unaudited Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>010100 - Statement - Unaudited Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Unaudited Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>020000 - Statement - Unaudited Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedStatementsOfIncome</Role>
      <ShortName>Unaudited Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>030000 - Statement - Unaudited Consolidated Statements of Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedStatementsOfShareholdersEquity</Role>
      <ShortName>Unaudited Consolidated Statements of Shareholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>030100 - Statement - Unaudited Consolidated Statements of Shareholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedStatementsOfShareholdersEquityParenthetical</Role>
      <ShortName>Unaudited Consolidated Statements of Shareholders' Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>040000 - Statement - Unaudited Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/UnauditedConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Unaudited Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>060100 - Disclosure - Nature of Operations and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/NatureOfOperationsAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Nature of Operations and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>060200 - Disclosure - Change in Capital Structure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/ChangeInCapitalStructure</Role>
      <ShortName>Change in Capital Structure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>060300 - Disclosure - Restriction on Cash and Due from Banks</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RestrictionOnCashAndDueFromBanks</Role>
      <ShortName>Restriction on Cash and Due from Banks</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>060400 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>060500 - Disclosure - Loans and Allowance for Loan Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLosses</Role>
      <ShortName>Loans and Allowance for Loan Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>060600 - Disclosure - Regulatory Matters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RegulatoryMatters</Role>
      <ShortName>Regulatory Matters</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>060700 - Disclosure - Related-Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RelatedpartyTransactions</Role>
      <ShortName>Related-Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>060800 - Disclosure - Employee Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EmployeeBenefits</Role>
      <ShortName>Employee Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>060900 - Disclosure - Disclosures About Fair Value of Assets and Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilities</Role>
      <ShortName>Disclosures About Fair Value of Assets and Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>061000 - Disclosure - Financial Instruments with Off-Balance Sheet Risk</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/FinancialInstrumentsWithOffbalanceSheetRisk</Role>
      <ShortName>Financial Instruments with Off-Balance Sheet Risk</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>061100 - Disclosure - Significant Estimates and Concentrations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/SignificantEstimatesAndConcentrations</Role>
      <ShortName>Significant Estimates and Concentrations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>070100 - Disclosure - Nature of Operations and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/NatureOfOperationsAndSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Nature of Operations and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://bank7.com/role/NatureOfOperationsAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>080400 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/EarningsPerShare</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>080500 - Disclosure - Loans and Allowance for Loan Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesTables</Role>
      <ShortName>Loans and Allowance for Loan Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/LoansAndAllowanceForLoanLosses</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>080600 - Disclosure - Regulatory Matters (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RegulatoryMattersTables</Role>
      <ShortName>Regulatory Matters (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/RegulatoryMatters</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>080700 - Disclosure - Related-Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RelatedpartyTransactionsTables</Role>
      <ShortName>Related-Party Transactions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/RelatedpartyTransactions</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>080800 - Disclosure - Employee Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EmployeeBenefitsTables</Role>
      <ShortName>Employee Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/EmployeeBenefits</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>080900 - Disclosure - Disclosures About Fair Value of Assets and Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilitiesTables</Role>
      <ShortName>Disclosures About Fair Value of Assets and Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilities</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>081000 - Disclosure - Financial Instruments with Off-Balance Sheet Risk (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/FinancialInstrumentsWithOffbalanceSheetRiskTables</Role>
      <ShortName>Financial Instruments with Off-Balance Sheet Risk (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://bank7.com/role/FinancialInstrumentsWithOffbalanceSheetRisk</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>090200 - Disclosure - Change in Capital Structure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/ChangeInCapitalStructureDetails</Role>
      <ShortName>Change in Capital Structure (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/ChangeInCapitalStructure</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>090300 - Disclosure - Restriction on Cash and Due from Banks (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RestrictionOnCashAndDueFromBanksDetails</Role>
      <ShortName>Restriction on Cash and Due from Banks (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/RestrictionOnCashAndDueFromBanks</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>090400 - Disclosure - Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/EarningsPerShareTables</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>090500 - Disclosure - Loans and Allowance for Loan Losses, Summary of Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesSummaryOfLoansDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Summary of Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>090502 - Disclosure - Loans and Allowance for Loan Losses, Activity in Allowance for Loan Losses by Portfolio Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesActivityInAllowanceForLoanLossesByPortfolioSegmentDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Activity in Allowance for Loan Losses by Portfolio Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>090504 - Disclosure - Loans and Allowance for Loan Losses, Loan Portfolio Based on Internal Rating Category (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesLoanPortfolioBasedOnInternalRatingCategoryDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Loan Portfolio Based on Internal Rating Category (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>090506 - Disclosure - Loans and Allowance for Loan Losses, Loan Portfolio Aging Analysis of Recorded Investment in Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesLoanPortfolioAgingAnalysisOfRecordedInvestmentInLoansDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Loan Portfolio Aging Analysis of Recorded Investment in Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>090508 - Disclosure - Loans and Allowance for Loan Losses, Impaired Loans and TDR's (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesImpairedLoansAndTdrSDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Impaired Loans and TDR's (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>090510 - Disclosure - Loans and Allowance for Loan Losses, Information Regarding Nonperforming Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/LoansAndAllowanceForLoanLossesInformationRegardingNonperformingAssetsDetails</Role>
      <ShortName>Loans and Allowance for Loan Losses, Information Regarding Nonperforming Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>090600 - Disclosure - Regulatory Matters, Actual Capital Amounts and Ratios (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RegulatoryMattersActualCapitalAmountsAndRatiosDetails</Role>
      <ShortName>Regulatory Matters, Actual Capital Amounts and Ratios (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>090602 - Disclosure - Regulatory Matters, Payout Restrictions Based on Capital Conservation Buffer (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RegulatoryMattersPayoutRestrictionsBasedOnCapitalConservationBufferDetails</Role>
      <ShortName>Regulatory Matters, Payout Restrictions Based on Capital Conservation Buffer (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>090700 - Disclosure - Related-Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/RelatedpartyTransactionsDetails</Role>
      <ShortName>Related-Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/RelatedpartyTransactionsTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>090800 - Disclosure - Employee Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/EmployeeBenefitsDetails</Role>
      <ShortName>Employee Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/EmployeeBenefitsTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>090900 - Disclosure - Disclosures About Fair Value of Assets and Liabilities, Recurring and Nonrecurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilitiesRecurringAndNonrecurringBasisDetails</Role>
      <ShortName>Disclosures About Fair Value of Assets and Liabilities, Recurring and Nonrecurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>090904 - Disclosure - Disclosures About Fair Value of Assets and Liabilities, Quantitative Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilitiesQuantitativeInformationDetails</Role>
      <ShortName>Disclosures About Fair Value of Assets and Liabilities, Quantitative Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>090906 - Disclosure - Disclosures About Fair Value of Assets and Liabilities, Financial Instruments not Recorded at Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/DisclosuresAboutFairValueOfAssetsAndLiabilitiesFinancialInstrumentsNotRecordedAtFairValueDetails</Role>
      <ShortName>Disclosures About Fair Value of Assets and Liabilities, Financial Instruments not Recorded at Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>091000 - Disclosure - Financial Instruments with Off-Balance Sheet Risk (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/FinancialInstrumentsWithOffbalanceSheetRiskDetails</Role>
      <ShortName>Financial Instruments with Off-Balance Sheet Risk (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/FinancialInstrumentsWithOffbalanceSheetRiskTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="bsvn-20190630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>091100 - Disclosure - Significant Estimates and Concentrations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://bank7.com/role/SignificantEstimatesAndConcentrationsDetails</Role>
      <ShortName>Significant Estimates and Concentrations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://bank7.com/role/SignificantEstimatesAndConcentrations</ParentRole>
      <Position>44</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>bsvn-20190630.xml</File>
    <File>bsvn-20190630.xsd</File>
    <File>bsvn-20190630_cal.xml</File>
    <File>bsvn-20190630_def.xml</File>
    <File>bsvn-20190630_lab.xml</File>
    <File>bsvn-20190630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
