<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.3</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>493</ContextCount>
  <ElementCount>491</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>86</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>995200090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>995200100 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>995200105 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>995200200 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>995200300 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>995200400 - Statement - Consolidated Statements of Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedStatementsOfShareholdersEquity</Role>
      <ShortName>Consolidated Statements of Shareholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>995200500 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>995210101 - Disclosure - Description of the Business and Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Description of the Business and Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>995210201 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995210301 - Disclosure - Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecurities</Role>
      <ShortName>Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995210401 - Disclosure - Loans and Allowance for Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLosses</Role>
      <ShortName>Loans and Allowance for Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995210501 - Disclosure - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssets</Role>
      <ShortName>Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995210601 - Disclosure - Deposits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDeposits</Role>
      <ShortName>Deposits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995210701 - Disclosure - Derivative Instruments and Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivities</Role>
      <ShortName>Derivative Instruments and Hedging Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995210801 - Disclosure - Federal Home Loan Bank Advances and Other Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowings</Role>
      <ShortName>Federal Home Loan Bank Advances and Other Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995210901 - Disclosure - Subordinated Debentures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSubordinatedDebentures</Role>
      <ShortName>Subordinated Debentures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995211001 - Disclosure - Commitments, Contingencies and Credit Risk</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRisk</Role>
      <ShortName>Commitments, Contingencies and Credit Risk</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995211101 - Disclosure - Stock Options and Restricted Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStock</Role>
      <ShortName>Stock Options and Restricted Stock</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995211201 - Disclosure - Regulatory Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureRegulatoryCapital</Role>
      <ShortName>Regulatory Capital</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995211301 - Disclosure - Fair Value Measurement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurement</Role>
      <ShortName>Fair Value Measurement</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995211401 - Disclosure - Accumulated Other Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncome</Role>
      <ShortName>Accumulated Other Comprehensive Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995211501 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.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>23</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>99920102 - Disclosure - Description of the Business and Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Description of the Business and Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>99930203 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureEarningsPerShare</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>99930303 - Disclosure - Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecuritiesTables</Role>
      <ShortName>Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureSecurities</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>99930403 - Disclosure - Loans and Allowance for Credit Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesTables</Role>
      <ShortName>Loans and Allowance for Credit Losses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLosses</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>99930503 - Disclosure - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssets</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>99930603 - Disclosure - Deposits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDepositsTables</Role>
      <ShortName>Deposits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureDeposits</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>99930703 - Disclosure - Derivative Instruments and Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesTables</Role>
      <ShortName>Derivative Instruments and Hedging Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivities</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>99930803 - Disclosure - Federal Home Loan Bank Advances and Other Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowingsTables</Role>
      <ShortName>Federal Home Loan Bank Advances and Other Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowings</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>99930903 - Disclosure - Subordinated Debentures (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSubordinatedDebenturesTables</Role>
      <ShortName>Subordinated Debentures (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureSubordinatedDebentures</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>99931003 - Disclosure - Commitments, Contingencies and Credit Risk (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRiskTables</Role>
      <ShortName>Commitments, Contingencies and Credit Risk (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRisk</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>99931103 - Disclosure - Stock Options Restricted Stock (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsRestrictedStockTables</Role>
      <ShortName>Stock Options Restricted Stock (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>99931203 - Disclosure - Regulatory Capital (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureRegulatoryCapitalTables</Role>
      <ShortName>Regulatory Capital (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureRegulatoryCapital</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>99931303 - Disclosure - Fair Value Measurement (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurementTables</Role>
      <ShortName>Fair Value Measurement (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurement</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>99931403 - Disclosure - Accumulated Other Comprehensive Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncome</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>99940101 - Disclosure - Description of the Business and Summary of Significant Accounting Policies - Recent Developments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesRecentDevelopmentsDetails</Role>
      <ShortName>Description of the Business and Summary of Significant Accounting Policies - Recent Developments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>99940201 - Disclosure - Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureEarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureEarningsPerShareTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>99940301 - Disclosure - Securities - Securities Available for Sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecuritiesSecuritiesAvailableForSaleDetails</Role>
      <ShortName>Securities - Securities Available for Sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>99940302 - Disclosure - Securities - Continuous Unrealized Loss Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecuritiesContinuousUnrealizedLossPositionDetails</Role>
      <ShortName>Securities - Continuous Unrealized Loss Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>99940303 - Disclosure - Securities - Contractual Maturities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecuritiesContractualMaturitiesDetails</Role>
      <ShortName>Securities - Contractual Maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>99940304 - Disclosure - Securities - Available for Sale Securities Gross Realized Gain Loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSecuritiesAvailableForSaleSecuritiesGrossRealizedGainLossDetails</Role>
      <ShortName>Securities - Available for Sale Securities Gross Realized Gain Loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>99940401 - Disclosure - Loans and Allowance for Credit Losses - Components of loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesComponentsOfLoansDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Components of loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>99940402 - Disclosure - Loans and Allowance for Credit Losses - Aging in past due loans and nonaccrual status, with and without an ACL, by loan segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesAgingInPastDueLoansAndNonaccrualStatusWithAndWithoutAclByLoanSegmentDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Aging in past due loans and nonaccrual status, with and without an ACL, by loan segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>99940403 - Disclosure - Loans and Allowance for Credit Losses - Risk category of loans by loan segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesRiskCategoryOfLoansByLoanSegmentDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Risk category of loans by loan segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>99940404 - Disclosure - Loans and Allowance for Credit Losses - Allowance for loan losses by segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesAllowanceForLoanLossesBySegmentDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Allowance for loan losses by segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>99940405 - Disclosure - Loans and Allowance for Credit Losses - Amortized cost basis of collateral dependent loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesAmortizedCostBasisOfCollateralDependentLoansDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Amortized cost basis of collateral dependent loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>99940406 - Disclosure - Loans and Allowance for Credit Losses - Additional information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureLoansAndAllowanceForCreditLossesAdditionalInformationDetails</Role>
      <ShortName>Loans and Allowance for Credit Losses - Additional information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>99940501 - Disclosure - Goodwill and Other Intangible Assets - (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssetsDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets - (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssetsTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>99940502 - Disclosure - Goodwill and Other Intangible Assets - Estimated future amortization (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureGoodwillAndOtherIntangibleAssetsEstimatedFutureAmortizationDetails</Role>
      <ShortName>Goodwill and Other Intangible Assets - Estimated future amortization (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>99940601 - Disclosure - Deposits - Composition of deposits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDepositsCompositionOfDepositsDetails</Role>
      <ShortName>Deposits - Composition of deposits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>99940602 - Disclosure - Deposits - Maturities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDepositsMaturitiesDetails</Role>
      <ShortName>Deposits - Maturities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>99940701 - Disclosure - Derivative Instruments and Hedging Activities - Non-hedge Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesNonHedgeDerivativesDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Non-hedge Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>99940702 - Disclosure - Derivative Instruments and Hedging Activities - RPA (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesRpaDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - RPA (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>99940703 - Disclosure - Derivative Instruments and Hedging Activities - Cash Flow Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesCashFlowDerivativesDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Cash Flow Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>99940704 - Disclosure - Derivative Instruments and Hedging Activities - Derivative Instruments in Cash Flow Hedging Relationships (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesDerivativeInstrumentsInCashFlowHedgingRelationshipsDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Derivative Instruments in Cash Flow Hedging Relationships (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>99940705 - Disclosure - Derivative Instruments and Hedging Activities - Fair Value Hedging Derivatives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesFairValueHedgingDerivativesDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Fair Value Hedging Derivatives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>99940706 - Disclosure - Derivative Instruments and Hedging Activities - Fair Value Hedging Relationships (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesFairValueHedgingRelationshipsDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Fair Value Hedging Relationships (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>99940707 - Disclosure - Derivative Instruments and Hedging Activities - Cash Flow Hedging Reclassification (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesCashFlowHedgingReclassificationDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Cash Flow Hedging Reclassification (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>99940708 - Disclosure - Derivative Instruments and Hedging Activities - Derivative instruments eligible for offset (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesDerivativeInstrumentsEligibleForOffsetDetails</Role>
      <ShortName>Derivative Instruments and Hedging Activities - Derivative instruments eligible for offset (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>99940801 - Disclosure - Federal Home Loan Bank Advances and Other Borrowings - Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowingsMaturityDetails</Role>
      <ShortName>Federal Home Loan Bank Advances and Other Borrowings - Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowingsTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>99940802 - Disclosure - Federal Home Loan Bank Advances and Other Borrowings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowingsDetails</Role>
      <ShortName>Federal Home Loan Bank Advances and Other Borrowings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureFederalHomeLoanBankAdvancesAndOtherBorrowingsTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>99940901 - Disclosure - Subordinated Debentures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSubordinatedDebenturesDetails</Role>
      <ShortName>Subordinated Debentures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureSubordinatedDebenturesTables</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>99941001 - Disclosure - Commitments, Contingencies and Credit Risk (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRiskDetails</Role>
      <ShortName>Commitments, Contingencies and Credit Risk (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRiskTables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>99941002 - Disclosure - Commitments, Contingencies and Credit Risk - Allowance for credit losses for off-balance sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureCommitmentsContingenciesAndCreditRiskAllowanceForCreditLossesForOffBalanceSheetDetails</Role>
      <ShortName>Commitments, Contingencies and Credit Risk - Allowance for credit losses for off-balance sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>99941101 - Disclosure - Stock Options and Restricted Stock - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockNarrativeDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>99941102 - Disclosure - Stock Options and Restricted Stock - Black-Scholes Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockBlackScholesAssumptionsDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Black-Scholes Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>99941103 - Disclosure - Stock Options and Restricted Stock - Stock Option Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockStockOptionPlansDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Stock Option Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>99941104 - Disclosure - Stock Options and Restricted Stock - Exercise Price (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockExercisePriceDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Exercise Price (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>99941105 - Disclosure - Stock Options and Restricted Stock - Non-Vested Options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockNonVestedOptionsDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Non-Vested Options (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>99941106 - Disclosure - Stock Options and Restricted Stock - Restricted Stock Awards (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockRestrictedStockAwardsDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Restricted Stock Awards (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>99941107 - Disclosure - Stock Options and Restricted Stock - Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureStockOptionsAndRestrictedStockRestrictedStockUnitsDetails</Role>
      <ShortName>Stock Options and Restricted Stock - Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>99941201 - Disclosure - Regulatory Capital - Capital Amounts and Ratios (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureRegulatoryCapitalCapitalAmountsAndRatiosDetails</Role>
      <ShortName>Regulatory Capital - Capital Amounts and Ratios (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>99941301 - Disclosure - Fair Value Measurement - Recurring (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurementRecurringDetails</Role>
      <ShortName>Fair Value Measurement - Recurring (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>99941302 - Disclosure - Fair Value Measurement - Nonrecurring (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurementNonrecurringDetails</Role>
      <ShortName>Fair Value Measurement - Nonrecurring (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>99941303 - Disclosure - Fair Value Measurement - Estimated Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureFairValueMeasurementEstimatedFairValueDetails</Role>
      <ShortName>Fair Value Measurement - Estimated Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>99941401 - Disclosure - Accumulated Other Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncomeTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>99941402 - Disclosure - Accumulated Other Comprehensive Income - Comprehensive income (loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureAccumulatedOtherComprehensiveIncomeComprehensiveIncomeLossDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income - Comprehensive income (loss) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="bwb-20250930x10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>99941501 - Disclosure - Subsequent Events (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bridgewaterbankmn.com/role/DisclosureSubsequentEventsDetails</Role>
      <ShortName>Subsequent Events (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.bridgewaterbankmn.com/role/DisclosureSubsequentEvents</ParentRole>
      <Position>81</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>bwb-20250930.xsd</File>
    <File>bwb-20250930_cal.xml</File>
    <File>bwb-20250930_def.xml</File>
    <File>bwb-20250930_lab.xml</File>
    <File>bwb-20250930_pre.xml</File>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="bwb-20250930x10q.htm">bwb-20250930x10q.htm</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="2241">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="32">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
