<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:ffd="http://xbrl.sec.gov/ffd/2025"
  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/2025/ffd-2025.xsd"
      xlink:type="simple"/>
    <context id="c_offering_1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002115404</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-03-24</startDate>
            <endDate>2026-03-24</endDate>
        </period>
    </context>
    <context id="c_offering_2">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002115404</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>2</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-03-24</startDate>
            <endDate>2026-03-24</endDate>
        </period>
    </context>
    <context id="c_offering_3">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002115404</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>3</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-03-24</startDate>
            <endDate>2026-03-24</endDate>
        </period>
    </context>
    <context id="c_offering_4">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002115404</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>4</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-03-24</startDate>
            <endDate>2026-03-24</endDate>
        </period>
    </context>
    <context id="c_report">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002115404</identifier>
        </entity>
        <period>
            <startDate>2026-03-24</startDate>
            <endDate>2026-03-24</endDate>
        </period>
    </context>
    <unit id="USD">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="pure">
        <measure>pure</measure>
    </unit>
    <unit id="shares">
        <measure>shares</measure>
    </unit>
    <ffd:SubmissnTp contextRef="c_report" id="fee_001">S-1</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="c_report" id="fee_002">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="c_report" id="fee_003">0002115404</dei:EntityCentralIndexKey>
    <ffd:OfferingTableNa contextRef="c_report" id="fee_004" xsi:nil="true"/>
    <ffd:OffsetTableNa contextRef="c_report" id="fee_005">N/A</ffd:OffsetTableNa>
    <ffd:CombinedProspectusTableNa contextRef="c_report" id="fee_006">N/A</ffd:CombinedProspectusTableNa>
    <ffd:FormTp contextRef="c_report" id="fee_007">S-1</ffd:FormTp>
    <dei:EntityRegistrantName contextRef="c_report" id="fee_008">Collective Acquisition Corp. II</dei:EntityRegistrantName>
    <ffd:PrevslyPdFlg contextRef="c_offering_1" id="fee_009">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c_offering_1" id="fee_010">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c_offering_1" id="fee_011">Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-third of one redeemable warrant</ffd:OfferingSctyTitl>
    <ffd:Rule457aFlg contextRef="c_offering_1" id="fee_012">true</ffd:Rule457aFlg>
    <ffd:AmtSctiesRegd
      contextRef="c_offering_1"
      decimals="0"
      id="fee_013"
      unitRef="shares">25300000</ffd:AmtSctiesRegd>
    <ffd:MaxOfferingPricPerScty
      contextRef="c_offering_1"
      decimals="INF"
      id="fee_014"
      unitRef="USD">10.00</ffd:MaxOfferingPricPerScty>
    <ffd:MaxAggtOfferingPric
      contextRef="c_offering_1"
      decimals="INF"
      id="fee_015"
      unitRef="USD">253000000.00</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate
      contextRef="c_offering_1"
      decimals="INF"
      id="fee_016"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt
      contextRef="c_offering_1"
      decimals="INF"
      id="fee_017"
      unitRef="USD">34939.30</ffd:FeeAmt>
    <ffd:PrevslyPdFlg contextRef="c_offering_2" id="fee_018">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c_offering_2" id="fee_019">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c_offering_2" id="fee_020">Class A ordinary shares included as part of the units</ffd:OfferingSctyTitl>
    <ffd:FeesOthrRuleFlg contextRef="c_offering_2" id="fee_021">true</ffd:FeesOthrRuleFlg>
    <ffd:AmtSctiesRegd
      contextRef="c_offering_2"
      decimals="0"
      id="fee_022"
      unitRef="shares">25300000</ffd:AmtSctiesRegd>
    <ffd:FeeRate
      contextRef="c_offering_2"
      decimals="INF"
      id="fee_023"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt
      contextRef="c_offering_2"
      decimals="INF"
      id="fee_024"
      unitRef="USD">0.00</ffd:FeeAmt>
    <ffd:PrevslyPdFlg contextRef="c_offering_3" id="fee_025">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c_offering_3" id="fee_026">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c_offering_3" id="fee_027">Redeemable warrants included as part of the units</ffd:OfferingSctyTitl>
    <ffd:FeesOthrRuleFlg contextRef="c_offering_3" id="fee_028">true</ffd:FeesOthrRuleFlg>
    <ffd:AmtSctiesRegd
      contextRef="c_offering_3"
      decimals="0"
      id="fee_029"
      unitRef="shares">8433333</ffd:AmtSctiesRegd>
    <ffd:FeeRate
      contextRef="c_offering_3"
      decimals="INF"
      id="fee_030"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt
      contextRef="c_offering_3"
      decimals="INF"
      id="fee_031"
      unitRef="USD">0.00</ffd:FeeAmt>
    <ffd:PrevslyPdFlg contextRef="c_offering_4" id="fee_032">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c_offering_4" id="fee_033">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c_offering_4" id="fee_034">Class A ordinary shares underlying redeemable warrants included as part of the units</ffd:OfferingSctyTitl>
    <ffd:Rule457aFlg contextRef="c_offering_4" id="fee_035">true</ffd:Rule457aFlg>
    <ffd:AmtSctiesRegd
      contextRef="c_offering_4"
      decimals="0"
      id="fee_036"
      unitRef="shares">8433333</ffd:AmtSctiesRegd>
    <ffd:MaxOfferingPricPerScty
      contextRef="c_offering_4"
      decimals="INF"
      id="fee_037"
      unitRef="USD">11.50</ffd:MaxOfferingPricPerScty>
    <ffd:MaxAggtOfferingPric
      contextRef="c_offering_4"
      decimals="INF"
      id="fee_038"
      unitRef="USD">96983329.50</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate
      contextRef="c_offering_4"
      decimals="INF"
      id="fee_039"
      unitRef="pure">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt
      contextRef="c_offering_4"
      decimals="INF"
      id="fee_040"
      unitRef="USD">13393.40</ffd:FeeAmt>
    <ffd:TtlOfferingAmt
      contextRef="c_report"
      decimals="INF"
      id="fee_041"
      unitRef="USD">349983329.50</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt
      contextRef="c_report"
      decimals="INF"
      id="fee_042"
      unitRef="USD">48332.70</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt
      contextRef="c_report"
      decimals="INF"
      id="fee_043"
      unitRef="USD">0.00</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt
      contextRef="c_report"
      decimals="INF"
      id="fee_044"
      unitRef="USD">0.00</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt
      contextRef="c_report"
      decimals="INF"
      id="fee_045"
      unitRef="USD">48332.70</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="c_offering_1" id="fee_046">Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(a).&lt;br/&gt;&lt;br/&gt;Includes 3,300,000 units, consisting of 3,300,000 Class A ordinary shares and 1,100,000 redeemable warrants, which may be issued upon exercise of a 45-day option granted to the underwriters to cover over-allotments, if any.&lt;br/&gt;</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="c_offering_2" id="fee_047">Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(a).&lt;br/&gt;&lt;br/&gt;Pursuant to Rule 416 under the Securities Act of 1933, as amended (the &#x201c;Securities Act&#x201d;), there are also being registered an indeterminable number of additional securities as may be issued to prevent dilution resulting from stock splits, stock dividends or similar transactions.&lt;br/&gt;&lt;br/&gt;No fee pursuant to Rule 457(g) under the Securities Act.&lt;br/&gt;</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="c_offering_3" id="fee_048">Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(a).&lt;br/&gt;&lt;br/&gt;Pursuant to Rule 416 under the Securities Act of 1933, as amended (the &#x201c;Securities Act&#x201d;), there are also being registered an indeterminable number of additional securities as may be issued to prevent dilution resulting from stock splits, stock dividends or similar transactions.&lt;br/&gt;&lt;br/&gt;No fee pursuant to Rule 457(g) under the Securities Act.&lt;br/&gt;</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="c_offering_4" id="fee_049">Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(a).&lt;br/&gt;&lt;br/&gt;Pursuant to Rule 416 under the Securities Act of 1933, as amended (the &#x201c;Securities Act&#x201d;), there are also being registered an indeterminable number of additional securities as may be issued to prevent dilution resulting from stock splits, stock dividends or similar transactions.</ffd:OfferingNote>
</xbrl>
