<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:ffd="http://xbrl.sec.gov/ffd/2026"
  xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <link:schemaRef
      xlink:href="https://xbrl.sec.gov/ffd/2026/ffd-2026.xsd"
      xlink:type="simple"/>
    <context id="rc">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001816389</identifier>
        </entity>
        <period>
            <startDate>2026-05-07</startDate>
            <endDate>2026-05-07</endDate>
        </period>
    </context>
    <context id="offrl_1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001816389</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-05-07</startDate>
            <endDate>2026-05-07</endDate>
        </period>
    </context>
    <unit id="USD">
        <measure>iso4217:USD</measure>
    </unit>
    <ffd:FormTp contextRef="rc" id="ixv-150">SC TO</ffd:FormTp>
    <ffd:SubmissnTp contextRef="rc" id="ixv-151">SC TO-I/A</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="rc" id="ixv-152">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="rc" id="ixv-153">0001816389</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-154">BlackRock Private Investments Fund</dei:EntityRegistrantName>
    <ffd:OfferingTableNa contextRef="rc" id="hiddenrcOfferingTableNa" xsi:nil="true"/>
    <ffd:OffsetTableNa contextRef="rc" id="hiddenrcOffsetTableNa">N/A</ffd:OffsetTableNa>
    <ffd:Rule011Flg contextRef="offrl_1" id="ixv-157">true</ffd:Rule011Flg>
    <ffd:PrevslyPdFlg contextRef="offrl_1" id="ixv-182">true</ffd:PrevslyPdFlg>
    <ffd:TxValtn
      contextRef="offrl_1"
      decimals="2"
      id="ixv-183"
      unitRef="USD">23492343.81</ffd:TxValtn>
    <ffd:FeeAmt
      contextRef="offrl_1"
      decimals="2"
      id="ixv-184"
      unitRef="USD">3244.29</ffd:FeeAmt>
    <ffd:TtlTxValtn contextRef="rc" decimals="2" id="ixv-185" unitRef="USD">23492343.81</ffd:TtlTxValtn>
    <ffd:TtlFeeAmt contextRef="rc" decimals="2" id="ixv-186" unitRef="USD">3244.29</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt contextRef="rc" decimals="2" id="ixv-187" unitRef="USD">3244.29</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt contextRef="rc" decimals="2" id="ixv-188" unitRef="USD">0.00</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="rc" decimals="2" id="ixv-189" unitRef="USD">0.00</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="offrl_1" id="ixv-190">(1) The transaction value is calculated as the aggregate maximum purchase price for Shares that could be purchased, based upon the net asset value of the Trust as of March 31, 2026. The fee of $3,244.29 was paid in connection with the filing of the Schedule TO-I by BlackRock Private Investments Fund (File No. 005-94022) on April 30, 2026 (the "Schedule TO"). This Amendment No. 1 to the Schedule TO is being filed to amend and supplement certain information contained in the Schedule TO and to file additional exhibits to the Schedule TO. (2) Calculated at $138.10 per $1,000,000 of the Transaction Value.</ffd:OfferingNote>
</xbrl>
