<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:bwb="http://www.bridgewaterbankmn.com/20250821"
  xmlns:dei="http://xbrl.sec.gov/dei/2024"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2024"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="bwb-20250821.xsd" xlink:type="simple"/>
    <context id="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_us-gaap_CommonStockMember_vSdqrZdcSkObq6t0MvI2Nw">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001341317</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">us-gaap:CommonStockMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-08-21</startDate>
            <endDate>2025-08-21</endDate>
        </period>
    </context>
    <context id="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_bwb_DepositarySharesMember_HSlHaxjKOUmUCooHK1VSqA">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001341317</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">bwb:DepositarySharesMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-08-21</startDate>
            <endDate>2025-08-21</endDate>
        </period>
    </context>
    <context id="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001341317</identifier>
        </entity>
        <period>
            <startDate>2025-08-21</startDate>
            <endDate>2025-08-21</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Tc_QvMSMP0ud0yxBUbOJqdAIw_2_1">0001341317</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Tc_vuHZsErHxUSXwLk2qrgevg_3_1">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_NnPjEaHyDUG3jM4AnDtqcw">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_rLNL5CFty0aRjfRTqAaElg">2025-08-21</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_E2WTAiJgNECmS1rFX-IxhA">BRIDGEWATER BANCSHARES, INC.</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_McRaszyp2Ua5m88cinctYQ">MN</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_rTyB3L4meUm-x2e7yslb9Q">001-38412</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_Uri_fdhdV0K0G3k9zKLbYA">26-0113412</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_R5r9nF0V_U-6s0EXlCKDjw">4450 Excelsior Boulevard, Suite 100</dei:EntityAddressAddressLine1>
    <dei:EntityAddressCityOrTown
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_P3-x8ej6FUKOUFPeHWhTZA">St. Louis Park</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_l7Rk-JeSgUO_qwjaqNSFvg">MN</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_4QKSf9Js8EKnGvcHF89Cbw">55416</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_eOYKJVjbHkSdy2jjnYCURw">952</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_SdEcLzBbKU6hdXkQIOF97A">893-6868</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_Su6sAhDnpUueDewBQm0h4w">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_uQyCYs3_0UeR2axOBzKLzg">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_A1SwXOkF80aN7aZGvkN_cQ">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr_bhea0CUePEedAsfKO-j_bw">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_us-gaap_CommonStockMember_vSdqrZdcSkObq6t0MvI2Nw"
      id="Narr_QKctU4_t7EOSP3KfukAGRg">Common Stock</dei:Security12bTitle>
    <dei:Security12bTitle
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_bwb_DepositarySharesMember_HSlHaxjKOUmUCooHK1VSqA"
      id="Narr_1lpNSBZ-XkufMrqrWPtcOw">Depositary Shares</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_us-gaap_CommonStockMember_vSdqrZdcSkObq6t0MvI2Nw"
      id="Narr_4aCtI7DSrEmPBpkzs7kkiQ">BWB</dei:TradingSymbol>
    <dei:TradingSymbol
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_bwb_DepositarySharesMember_HSlHaxjKOUmUCooHK1VSqA"
      id="Narr_Hk2XUlmab0-ixo_PnHr2ww">BWBBP</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_us-gaap_CommonStockMember_vSdqrZdcSkObq6t0MvI2Nw"
      id="Narr__ExU2mgNiUiqQiD8xxilzw">NASDAQ</dei:SecurityExchangeName>
    <dei:SecurityExchangeName
      contextRef="Duration_8_21_2025_To_8_21_2025_us-gaap_StatementClassOfStockAxis_bwb_DepositarySharesMember_HSlHaxjKOUmUCooHK1VSqA"
      id="Narr_NMOfYovMfEimE1rPQhnzKA">NASDAQ</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="Duration_8_21_2025_To_8_21_2025_ebffSoFCM0eURRUSNyuCqw"
      id="Narr__3PdItdAR0eAbuX2YcR8BQ">false</dei:EntityEmergingGrowthCompany>
</xbrl>
