<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>169</ContextCount>
  <ElementCount>270</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>72</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/Coverpage</Role>
      <ShortName>Cover page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - Condensed Consolidated Balance Sheets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - Condensed Consolidated Statements of Income (Loss) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedStatementsofIncomeLossUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Income (Loss) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952155 - Statement - Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeLossUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952156 - Statement - Condensed Consolidated Statements of Cash Flow (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedStatementsofCashFlowUnaudited</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flow (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952157 - Statement - Condensed Consolidated Statement of Stockholders' Equity (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedStatementofStockholdersEquityUnaudited</Role>
      <ShortName>Condensed Consolidated Statement of Stockholders' Equity (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952158 - Statement - Condensed Consolidated Statement of Stockholders' Equity (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/CondensedConsolidatedStatementofStockholdersEquityUnauditedParenthetical</Role>
      <ShortName>Condensed Consolidated Statement of Stockholders' Equity (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - Nature of Operations and Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentation</Role>
      <ShortName>Nature of Operations and Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/Inventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Property, Plant &amp; Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/PropertyPlantEquipment</Role>
      <ShortName>Property, Plant &amp; Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Goodwill and Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/GoodwillandIntangibleAssets</Role>
      <ShortName>Goodwill and Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Debt and Finance Lease Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/DebtandFinanceLeaseObligations</Role>
      <ShortName>Debt and Finance Lease Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Retirement Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/RetirementPlans</Role>
      <ShortName>Retirement Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/Contingencies</Role>
      <ShortName>Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Fair Value Measurement of Assets and Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/FairValueMeasurementofAssetsandLiabilities</Role>
      <ShortName>Fair Value Measurement of Assets and Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensation</Role>
      <ShortName>Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Other, net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/Othernet</Role>
      <ShortName>Other, net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - New Accounting Guidance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/NewAccountingGuidance</Role>
      <ShortName>New Accounting Guidance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="nx-20260131.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="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Nature of Operations and Basis of Presentation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentationTables</Role>
      <ShortName>Nature of Operations and Basis of Presentation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentation</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/InventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/Inventories</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - Property, Plant &amp; and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/PropertyPlantandEquipmentTables</Role>
      <ShortName>Property, Plant &amp; and Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Goodwill and Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/GoodwillandIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/GoodwillandIntangibleAssets</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Debt and Finance Lease Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/DebtandFinanceLeaseObligationsTables</Role>
      <ShortName>Debt and Finance Lease Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/DebtandFinanceLeaseObligations</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationTables</Role>
      <ShortName>Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/StockBasedCompensation</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Other, net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/OthernetTables</Role>
      <ShortName>Other, net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/Othernet</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/SegmentInformation</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/EarningsPerShare</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Nature of Operations and Basis of Presentation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentationDetails</Role>
      <ShortName>Nature of Operations and Basis of Presentation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentationTables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Nature of Operations and Basis of Presentation Summary of Product Sales (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/NatureofOperationsandBasisofPresentationSummaryofProductSalesDetails</Role>
      <ShortName>Nature of Operations and Basis of Presentation Summary of Product Sales (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Inventories (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/InventoriesDetail</Role>
      <ShortName>Inventories (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/InventoriesTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Property, Plant &amp; and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/PropertyPlantandEquipmentDetails</Role>
      <ShortName>Property, Plant &amp; and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/PropertyPlantandEquipmentTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Goodwill and Intangible Assets - Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/GoodwillandIntangibleAssetsGoodwillDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - Goodwill and Intangible Assets - Identifiable Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/GoodwillandIntangibleAssetsIdentifiableIntangibleAssetsDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Identifiable Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Debt and Finance Lease Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/DebtandFinanceLeaseObligationsDetails</Role>
      <ShortName>Debt and Finance Lease Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/DebtandFinanceLeaseObligationsTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - Retirement Plans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/RetirementPlansDetail</Role>
      <ShortName>Retirement Plans (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/RetirementPlans</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Income Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/IncomeTaxesDetail</Role>
      <ShortName>Income Taxes (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/IncomeTaxes</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Fair Value Measurement of Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/FairValueMeasurementofAssetsandLiabilitiesDetails</Role>
      <ShortName>Fair Value Measurement of Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/FairValueMeasurementofAssetsandLiabilities</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Stock Based Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationDetails</Role>
      <ShortName>Stock Based Compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Stock-Based Compensation - Restricted Stock Awards (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationRestrictedStockAwardsDetails</Role>
      <ShortName>Stock-Based Compensation - Restricted Stock Awards (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - Stock-Based Compensation - Stock Options (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationStockOptionsDetails</Role>
      <ShortName>Stock-Based Compensation - Stock Options (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Stock-Based Compensation - Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationRestrictedStockUnitsDetails</Role>
      <ShortName>Stock-Based Compensation - Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Stock-Based Compensation - Performance Share Awards (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationPerformanceShareAwardsDetails</Role>
      <ShortName>Stock-Based Compensation - Performance Share Awards (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Stock-Based Compensation - Performance Restricted Stock Units (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationPerformanceRestrictedStockUnitsDetails</Role>
      <ShortName>Stock-Based Compensation - Performance Restricted Stock Units (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Stock-Based Compensation - Treasury Shares (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/StockBasedCompensationTreasurySharesDetails</Role>
      <ShortName>Stock-Based Compensation - Treasury Shares (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Other, net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/OthernetDetails</Role>
      <ShortName>Other, net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/OthernetTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Segment Information -Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformationNarrativeDetails</Role>
      <ShortName>Segment Information -Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Segment Information Segment Reporting Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformationSegmentReportingInformationDetails</Role>
      <ShortName>Segment Information Segment Reporting Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Segment Information Goodwill by Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformationGoodwillbySegmentDetails</Role>
      <ShortName>Segment Information Goodwill by Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Segment Information Reconciliation of Operating Income to Net Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/SegmentInformationReconciliationofOperatingIncometoNetIncomeDetails</Role>
      <ShortName>Segment Information Reconciliation of Operating Income to Net Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="nx-20260131.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.quanexbuildingproducts.com/role/EarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.quanexbuildingproducts.com/role/EarningsPerShareTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="nx-20260131.htm">nx-20260131.htm</File>
    <File>nx-20260131.xsd</File>
    <File>nx-20260131_cal.xml</File>
    <File>nx-20260131_def.xml</File>
    <File>nx-20260131_lab.xml</File>
    <File>nx-20260131_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="729">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="30">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="5">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
