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    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_4bedeb4e-ca4c-4615-b015-069b7173f3a2_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value of plan assets</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_73e47513-cc63-41c0-ae72-0c5f6252c010_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
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    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_028e1aa9-0391-46f0-b1b9-ddc77a283a38_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other</link:label>
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    <link:label id="lab_nx_EarningsPerShareDisclosureTable_cd787e69-4b5d-4e14-a400-417877dc7942_terseLabel_en-US" xlink:label="lab_nx_EarningsPerShareDisclosureTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share Disclosure [Table]</link:label>
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    <link:label id="lab_country_GB_7a2473b0-a643-4ac6-99de-65d5e2181cb1_terseLabel_en-US" xlink:label="lab_country_GB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">UNITED KINGDOM</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_c03ddf28-d7b7-40c5-9ac0-626c44923dc8_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected return on plan assets</link:label>
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    <link:label id="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid_fce64f56-af7c-49e1-9c43-2759bddf33d6_terseLabel_en-US" xlink:label="lab_us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Change in capitalized expenditures in accounts payable and accrued liabilities</link:label>
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    <link:label id="lab_us-gaap_DerivativesPolicyTextBlock_8bb59432-5cbe-48ee-83f0-582e41f569e4_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativesPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Derivatives, Policy</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_743f7e2d-8f84-45d5-a3e5-73ff8f7e8682_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period</link:label>
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    <link:label id="lab_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_df862ba6-4d58-48d3-8b39-3bea285fd2c7_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted Average Dilutive Securities</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_5090dca8-a8b5-470a-97bd-1d3db7d8ef4f_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_46c70b3a-26d0-4d58-a87f-2db6e4c1f395_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Product Sales</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from External Customers by Products and Services [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_b22506cd-44ee-400d-9796-48c2c6399a7c_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for doubtful accounts</link:label>
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    <link:label id="lab_us-gaap_StateAndLocalJurisdictionMember_9bf9e2e5-dcc6-4e31-bdaa-e82b4fbb25b6_terseLabel_en-US" xlink:label="lab_us-gaap_StateAndLocalJurisdictionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">State</link:label>
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    <link:label id="lab_nx_RelatedPartyLeaseMember_6006a1dd-7c85-4bb8-b629-75b07bff7ebf_terseLabel_en-US" xlink:label="lab_nx_RelatedPartyLeaseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Lease</link:label>
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    <link:label id="lab_nx_RelatedPartyLeaseMember_documentation_en-US" xlink:label="lab_nx_RelatedPartyLeaseMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Lease</link:label>
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    <link:label id="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseOther_721402c6-b877-4a25-98fd-62b9191d0507_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsTaxDeferredExpenseOther" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other</link:label>
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    <link:label id="lab_us-gaap_Liabilities_3aad43fb-5687-456d-9c99-7ee491aa2dcb_totalLabel_en-US" xlink:label="lab_us-gaap_Liabilities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total liabilities</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Liabilities" xlink:to="lab_us-gaap_Liabilities" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_SalesMember_399347dc-030c-4d95-90c3-080ab7f2c748_terseLabel_en-US" xlink:label="lab_us-gaap_SalesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sales</link:label>
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    <link:label id="lab_us-gaap_LandImprovementsMember_7c332d2e-d24b-4c5d-849f-2986a4d8a15d_terseLabel_en-US" xlink:label="lab_us-gaap_LandImprovementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Land Improvements</link:label>
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    <link:label id="lab_dei_EntityRegistrantName_f740a813-9461-4ac1-a5f5-f14078cc9435_terseLabel_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Registrant Name</link:label>
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    <link:label id="lab_nx_AmountPurchasedUnderPurchaseObligations_c42ab57f-f774-4cb3-b9a5-e5bf85b565b3_terseLabel_en-US" xlink:label="lab_nx_AmountPurchasedUnderPurchaseObligations" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount purchased under purchase obligations</link:label>
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    <link:label id="lab_nx_DebtInstrumentRequiredCoverageRatio_4eb5e880-f3a2-43f6-be60-b3e304293ba0_terseLabel_en-US" xlink:label="lab_nx_DebtInstrumentRequiredCoverageRatio" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Required coverage ratio</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_c5ac7661-fb8a-4c53-b8e0-2b12eefd02aa_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Weighted Average Discount Rate, Percent</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
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    <link:label id="lab_us-gaap_ConcentrationRiskLineItems_52369213-5cec-4275-8930-b659ad0a3cf3_terseLabel_en-US" xlink:label="lab_us-gaap_ConcentrationRiskLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Risk [Line Items]</link:label>
    <link:label id="lab_us-gaap_ConcentrationRiskLineItems_label_en-US" xlink:label="lab_us-gaap_ConcentrationRiskLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Concentration Risk [Line Items]</link:label>
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    <link:label id="lab_us-gaap_AssetImpairmentCharges_6811247c-bc17-4b51-ae54-9b05ba9d9127_terseLabel_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset impairment charges</link:label>
    <link:label id="lab_us-gaap_AssetImpairmentCharges_label_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Impairment Charges</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetImpairmentCharges" xlink:to="lab_us-gaap_AssetImpairmentCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IntersegmentEliminationMember_aa369334-3db6-4f6e-8b3d-c4e3d7d66bc0_terseLabel_en-US" xlink:label="lab_us-gaap_IntersegmentEliminationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Intersegment Eliminations</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntersegmentEliminationMember" xlink:to="lab_us-gaap_IntersegmentEliminationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCompensationLiabilityCurrent_95cfac61-9c68-48dd-81ac-89c3fd4f910e_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCompensationLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred compensation</link:label>
    <link:label id="lab_us-gaap_DeferredCompensationLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_DeferredCompensationLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Compensation Liability, Current</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCompensationLiabilityCurrent" xlink:to="lab_us-gaap_DeferredCompensationLiabilityCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_a3a9ce1b-d51f-4776-8fa6-e1e24f71adfe_terseLabel_en-US" xlink:label="lab_nx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted Average Remaining Contractual Life</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:to="lab_nx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CustomerRefundLiabilityCurrent_9cb12700-fc55-4869-b00f-01e0a6920612_terseLabel_en-US" xlink:label="lab_us-gaap_CustomerRefundLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sales allowances</link:label>
    <link:label id="lab_us-gaap_CustomerRefundLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_CustomerRefundLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Customer Refund Liability, Current</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CustomerRefundLiabilityCurrent" xlink:to="lab_us-gaap_CustomerRefundLiabilityCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_aa64d4c1-da5b-47b8-bf35-eadd826986b0_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Undiscounted Excess Amount</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_PerformanceSharesSettledinCash_14729428-9ed1-484b-8a02-baeeea4e2df5_terseLabel_en-US" xlink:label="lab_nx_PerformanceSharesSettledinCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance shares settled in cash</link:label>
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    <link:label id="lab_nx_PerformanceSharesSettledinCash_documentation_en-US" xlink:label="lab_nx_PerformanceSharesSettledinCash" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance Shares Settled in Cash</link:label>
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    <link:label id="lab_us-gaap_PaymentsOfDividendsCommonStock_b3b0dcfa-e7c1-4b35-b9ab-8aa8d6a5ddc3_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDividendsCommonStock" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock dividends paid</link:label>
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    <link:label id="lab_us-gaap_DebtAndCapitalLeaseObligationsAbstract_543e4310-2bc7-407d-888a-1621e8e052f2_terseLabel_en-US" xlink:label="lab_us-gaap_DebtAndCapitalLeaseObligationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Aggregate Maturities</link:label>
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    <link:label id="lab_us-gaap_IntangibleAssetsNetIncludingGoodwill_label_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Intangible Assets, Net (Including Goodwill)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="lab_us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAxis_dfa60d7d-56cd-41fa-ad07-e604f98b7ff6_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transaction [Axis]</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionAxis_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transaction [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_0f36e259-f4d6-4fb6-a62e-e16ae3b60974_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Policy</link:label>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_HighqualitycorebondMember_d778d2ae-ddd9-4b6d-aa55-52ae0fc21e97_terseLabel_en-US" xlink:label="lab_nx_HighqualitycorebondMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">High-quality core bond</link:label>
    <link:label id="lab_nx_HighqualitycorebondMember_label_en-US" xlink:label="lab_nx_HighqualitycorebondMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">High quality core bond [Member]</link:label>
    <link:label id="lab_nx_HighqualitycorebondMember_documentation_en-US" xlink:label="lab_nx_HighqualitycorebondMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Mutual fund investment in a fudn that is composed of a variety of bonds that are in combination designed to provide a safe bond investment.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_HighqualitycorebondMember" xlink:href="nx-20201031.xsd#nx_HighqualitycorebondMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_HighqualitycorebondMember" xlink:to="lab_nx_HighqualitycorebondMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InventoryDisclosureAbstract_fc11261b-c835-4b43-9d0e-6526b47502c6_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_InventoryDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_InventoryDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryDisclosureAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryDisclosureAbstract" xlink:to="lab_us-gaap_InventoryDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_ed3ee24f-c438-427a-b5e3-7296283f77c5_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Performance shares vesting percentage</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod_44b33be4-65c0-4931-970b-22a5dd5c62aa_terseLabel_en-US" xlink:label="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deprecation and accretion period</link:label>
    <link:label id="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod_label_en-US" xlink:label="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cumulative Asset Retirement Obligation, Deprecation and Accretion Period</link:label>
    <link:label id="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod_documentation_en-US" xlink:label="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cumulative Asset Retirement Obligation, Deprecation and Accretion Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:href="nx-20201031.xsd#nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:to="lab_nx_CumulativeAssetRetirementObligationDeprecationAndAccretionPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_e7866146-1a7b-483c-9d23-6e78076f1ed7_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, shares, issued (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_05d84b71-44aa-46f4-9457-37df95bf87fb_periodStartLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, shares</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_4e27d86a-eeda-4d2a-b013-bebdaf8d7240_periodEndLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, shares</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesIssued_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Shares, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesIssued" xlink:to="lab_us-gaap_CommonStockSharesIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_d6138051-6654-43d7-8108-38760a1a1639_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_SmallcapitilizationMember_5bb215e9-d4f6-47e5-a726-bf76275a4782_terseLabel_en-US" xlink:label="lab_nx_SmallcapitilizationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Small capitalization</link:label>
    <link:label id="lab_nx_SmallcapitilizationMember_label_en-US" xlink:label="lab_nx_SmallcapitilizationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Small capitilization [Member]</link:label>
    <link:label id="lab_nx_SmallcapitilizationMember_documentation_en-US" xlink:label="lab_nx_SmallcapitilizationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This category includes information about ownership interests mutual funds that contains small capitalization stocks.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_SmallcapitilizationMember" xlink:href="nx-20201031.xsd#nx_SmallcapitilizationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_SmallcapitilizationMember" xlink:to="lab_nx_SmallcapitilizationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount_6e3946ac-b00e-4d51-ae70-d50b5dbcf968_terseLabel_en-US" xlink:label="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity, Committed Amount</link:label>
    <link:label id="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount_label_en-US" xlink:label="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity, Committed Amount</link:label>
    <link:label id="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount_documentation_en-US" xlink:label="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity, Committed Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:href="nx-20201031.xsd#nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:to="lab_nx_LineofCreditFacilityMaximumBorrowingCapacityCommittedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_0531a155-6e0c-4f12-853b-e2f470c8a853_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiability" xlink:to="lab_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxLiabilities_804b071f-79c5-431a-b076-7cf611be4505_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net deferred tax liabilities</link:label>
    <link:label id="lab_us-gaap_DeferredTaxLiabilities_label_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Liabilities, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxLiabilities" xlink:to="lab_us-gaap_DeferredTaxLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree_c892a4fb-5e7f-4d55-987d-b48c447a5550_verboseLabel_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2023</link:label>
    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree_label_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, And Other Financing Obligations, To Be Paid, Year Three</link:label>
    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree_documentation_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, And Other Financing Obligations, To Be Paid, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:href="nx-20201031.xsd#nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:to="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_50c409ca-00a4-49d6-b69e-204bdb9418cb_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract" xlink:to="lab_us-gaap_SegmentReportingAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_AsiaMember_0b1bfe8f-eaec-4658-a05b-ab73a48f8c69_terseLabel_en-US" xlink:label="lab_srt_AsiaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asia</link:label>
    <link:label id="lab_srt_AsiaMember_label_en-US" xlink:label="lab_srt_AsiaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asia [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_AsiaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_AsiaMember" xlink:to="lab_srt_AsiaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_b3e1928a-a996-4d07-b87f-b0b75406b1bb_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentLineItems" xlink:to="lab_us-gaap_DebtInstrumentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquity_8efe73d9-6cd8-4a63-a38f-9988bf764c5f_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total stockholders&#8217; equity</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquity_234f6bea-610b-4249-bfba-623433008979_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' equity, value</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Attributable to Parent</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_EUEngineeredComponentsMember_f49372dc-348d-4fb2-9d7d-046010cc3690_terseLabel_en-US" xlink:label="lab_nx_EUEngineeredComponentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">EU Engineered Components</link:label>
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    <link:label id="lab_nx_EUEngineeredComponentsMember_documentation_en-US" xlink:label="lab_nx_EUEngineeredComponentsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">EU Engineered Components [Member]</link:label>
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    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour_6fcd0167-e66b-44ed-b039-c8473dbe54c5_terseLabel_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2024</link:label>
    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour_label_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, And Other Financing Obligations, To Be Paid, Year Four</link:label>
    <link:label id="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour_documentation_en-US" xlink:label="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, And Other Financing Obligations, To Be Paid, Year Four</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour" xlink:to="lab_nx_FinanceLeaseLiabilityAndOtherFinancingObligationsToBePaidYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_InventoryReserveRollforwardTableTextBlock_f6717926-ccf9-452f-ba30-295096e2ea02_terseLabel_en-US" xlink:label="lab_nx_InventoryReserveRollforwardTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory Reserve Rollforward</link:label>
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    <link:label id="lab_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent_648c5a33-b825-4c37-a184-b5991f2e2240_terseLabel_en-US" xlink:label="lab_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued insurance and workers compensation</link:label>
    <link:label id="lab_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Employee-related Liabilities, Current</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherEmployeeRelatedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueRecognitionDeferredRevenue_47c34e93-be17-48c3-8c1d-00f079540fee_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRecognitionDeferredRevenue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue From Contracts with Customers, Policy</link:label>
    <link:label id="lab_us-gaap_RevenueRecognitionDeferredRevenue_label_en-US" xlink:label="lab_us-gaap_RevenueRecognitionDeferredRevenue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue Recognition, Deferred Revenue [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRecognitionDeferredRevenue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueRecognitionDeferredRevenue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRecognitionDeferredRevenue" xlink:to="lab_us-gaap_RevenueRecognitionDeferredRevenue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InventoryRawMaterials_69e3f864-1976-4860-b633-21c6b231a286_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryRawMaterials" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Raw materials</link:label>
    <link:label id="lab_us-gaap_InventoryRawMaterials_label_en-US" xlink:label="lab_us-gaap_InventoryRawMaterials" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory, Raw Materials, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryRawMaterials" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InventoryRawMaterials"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryRawMaterials" xlink:to="lab_us-gaap_InventoryRawMaterials" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressCityOrTown_e711ef47-5ec0-4dc7-a65e-05de62ffb143_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressCityOrTown"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressCityOrTown" xlink:to="lab_dei_EntityAddressCityOrTown" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_c9a70eae-fedd-43b6-9e9e-80909859fb3c_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payroll, payroll taxes and employee benefits</link:label>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee-related Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:to="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_fb75649d-b484-4c5f-b435-10f3ab87f6e8_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_ac8470b9-cfed-4e53-a3cb-7dfa7a8d6127_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Stock Units (RSUs)</link:label>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_label_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Stock Units (RSUs) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_110daf6a-b810-4e5e-9de0-2a470f88ebd1_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_e8d50a4c-6cec-45d0-828a-f17b1def68f5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Loss (gain) on disposition of capital assets</link:label>
    <link:label id="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_label_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gain (Loss) on Disposition of Property Plant Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
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    <link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_6a912b07-3314-4b65-8133-47b8c68bfdba_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Less: Valuation allowance</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsValuationAllowance_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Assets, Valuation Allowance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="lab_us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_e7b2d0aa-779c-4f9b-bd14-e23577f2b878_terseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2020</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityNoncurrent_1f536038-2efb-4a21-ba27-52443406fcbc_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Noncurrent</link:label>
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    <link:label id="lab_us-gaap_LeasesAbstract_label_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases [Abstract]</link:label>
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    <link:label id="lab_nx_InternationalEquityMember_documentation_en-US" xlink:label="lab_nx_InternationalEquityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This category includes information about ownership interests mutual funds that contains international company stocks.</link:label>
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    <link:label id="lab_us-gaap_LongtermDebtTypeAxis_f1f86189-f42f-49e9-a70d-8df5b55acf19_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Type [Axis]</link:label>
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    <link:label id="lab_us-gaap_AssetsCurrent_d1bca7d5-9058-4707-8652-2f8a5e41d477_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total current assets</link:label>
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    <link:label id="lab_us-gaap_OperatingLossCarryforwards_4027e0b5-5bc7-4857-9f20-9faa77615e4e_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating loss carryforwards</link:label>
    <link:label id="lab_us-gaap_OperatingLossCarryforwards_label_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwards" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Loss Carryforwards</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
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    <link:label id="lab_us-gaap_EarningsPerShareAbstract_d28312b3-33cd-4e83-b62d-a1e5b35a515f_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareAbstract" xlink:to="lab_us-gaap_EarningsPerShareAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestructuringCharges_77094400-5d75-4b9c-90a3-b8cc193892e3_terseLabel_en-US" xlink:label="lab_us-gaap_RestructuringCharges" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restructuring charges</link:label>
    <link:label id="lab_us-gaap_RestructuringCharges_label_en-US" xlink:label="lab_us-gaap_RestructuringCharges" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restructuring Charges</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestructuringCharges"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestructuringCharges" xlink:to="lab_us-gaap_RestructuringCharges" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_12e51f9a-d3ae-4883-a59f-9b03c1768df8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Assets and Liabilities</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Deferred Tax Assets and Liabilities [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_41bde768-55e9-4fd9-b8dc-b9873e4de393_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">State and local income tax</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquityAbstract_a366ea1f-4056-46d1-bf20-fc5e44841bc5_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders&#8217; equity:</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Attributable to Parent [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityAbstract" xlink:to="lab_us-gaap_StockholdersEquityAbstract" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finite-Lived Intangible Asset, Expected Amortization, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_SubsequentEventsPolicyPolicyTextBlock_a7e05128-45e3-4281-b553-47567d9fdddd_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventsPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Subsequent Events, Policy</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventsPolicyPolicyTextBlock" xlink:to="lab_us-gaap_SubsequentEventsPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer_935830e5-367a-479c-93bb-244e0bd33974_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employer contributions</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityFilerCategory" xlink:to="lab_dei_EntityFilerCategory" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockMember_dfe599ba-c395-4727-b2e1-e1cb3255a977_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock</link:label>
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    <link:label id="lab_us-gaap_AccountsPayableCurrent_97a9fc14-57fe-4635-8e45-079344732288_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts payable</link:label>
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    <link:label id="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_72f265a6-9f62-4d81-acd0-fc73e2200c21_verboseLabel_en-US" xlink:label="lab_us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Foreign currency translation adjustment</link:label>
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    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_ce2fb772-5f2b-430c-8c0b-ebf13476e88b_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retained earnings</link:label>
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    <link:label id="lab_nx_TermLoanFacilityMember_1129c35c-04a4-44dc-a4fc-672cb44b3092_terseLabel_en-US" xlink:label="lab_nx_TermLoanFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Term Loan Facility [Member]</link:label>
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    <link:label id="lab_nx_TermLoanFacilityMember_documentation_en-US" xlink:label="lab_nx_TermLoanFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Term Loan Facility [Member]</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfLinesOfCredit_26198584-664b-4a0b-bdb0-7845666073f0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLinesOfCredit" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Repayments of credit facility borrowings</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_6598f8fb-1066-421e-9be8-5ff3820fe714_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease right-of-use assets</link:label>
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    <link:label id="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_ba5eaad8-e457-467f-b3d0-f9d3de0af344_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, plant and equipment</link:label>
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    <link:label id="lab_nx_LongTermDebtAndCapitalLeaseObligationsGross_46b42fd8-e844-4a9b-afae-5a1f56303a91_totalLabel_en-US" xlink:label="lab_nx_LongTermDebtAndCapitalLeaseObligationsGross" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term debt</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxesPaid_514d7d14-d11c-4a06-84fb-6562bbf9bf52_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaid" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash paid for income taxes</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_279fd739-35ba-4854-b511-1c758a1a008e_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2021</link:label>
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    <link:label id="lab_srt_MajorCustomersAxis_adf37bc4-b087-4a72-a09f-52d1b0ecd619_terseLabel_en-US" xlink:label="lab_srt_MajorCustomersAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Customer [Axis]</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_2f02d400-e9aa-4750-9ea4-3a3e0967aab2_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Tax, Policy</link:label>
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    <link:label id="lab_us-gaap_USTreasuryAndGovernmentMember_de3cf47e-8191-4b81-828f-65706b7678ee_terseLabel_en-US" xlink:label="lab_us-gaap_USTreasuryAndGovernmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">High-quality government bond</link:label>
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    <link:label id="lab_us-gaap_MachineryAndEquipmentGross_d838307d-f0c0-4b74-990e-44edb02e39e7_terseLabel_en-US" xlink:label="lab_us-gaap_MachineryAndEquipmentGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Machinery and equipment</link:label>
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    <link:label id="lab_us-gaap_ConstructionInProgressGross_62133266-d4d4-47bb-9352-ea34e2ac7bc8_terseLabel_en-US" xlink:label="lab_us-gaap_ConstructionInProgressGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Construction in progress</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConstructionInProgressGross" xlink:to="lab_us-gaap_ConstructionInProgressGross" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_06068a6d-091f-4527-ad36-3e65461ff1ae_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt, Maturity, after Year Five</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_2e31df4f-4520-412e-95bc-1066edc513aa_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Settlements</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanSettlementsBenefitObligation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:to="lab_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_GreaterThanThreeLeverageRatioMember_58d7353c-43e0-48fc-96ae-1f57803cece4_verboseLabel_en-US" xlink:label="lab_nx_GreaterThanThreeLeverageRatioMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Greater Than Three Leverage Ratio [Member]</link:label>
    <link:label id="lab_nx_GreaterThanThreeLeverageRatioMember_92484cd9-8ee5-417b-86bb-b64a7262fcfb_terseLabel_en-US" xlink:label="lab_nx_GreaterThanThreeLeverageRatioMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Greater than 3.00 to 1.00</link:label>
    <link:label id="lab_nx_GreaterThanThreeLeverageRatioMember_label_en-US" xlink:label="lab_nx_GreaterThanThreeLeverageRatioMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Greater Than Three Leverage Ratio [Member]</link:label>
    <link:label id="lab_nx_GreaterThanThreeLeverageRatioMember_documentation_en-US" xlink:label="lab_nx_GreaterThanThreeLeverageRatioMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Greater Than Three Leverage Ratio</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_GreaterThanThreeLeverageRatioMember" xlink:href="nx-20201031.xsd#nx_GreaterThanThreeLeverageRatioMember"/>
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    <link:label id="lab_nx_SwingLineMember_b3c464a2-b8b2-44a2-8541-637db8176e7a_terseLabel_en-US" xlink:label="lab_nx_SwingLineMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Swing Line [Member]</link:label>
    <link:label id="lab_nx_SwingLineMember_label_en-US" xlink:label="lab_nx_SwingLineMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Swing Line [Member]</link:label>
    <link:label id="lab_nx_SwingLineMember_documentation_en-US" xlink:label="lab_nx_SwingLineMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Swing Line</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_SwingLineMember" xlink:href="nx-20201031.xsd#nx_SwingLineMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_nx_SwingLineMember" xlink:to="lab_nx_SwingLineMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_62f5331f-27e2-43b3-ab9c-e434bda97da8_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Acquisition [Axis]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Acquisition [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionAxis" xlink:to="lab_us-gaap_BusinessAcquisitionAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_nx_NonfenestrationMember_dfd350c0-f40b-4f84-8041-134ebc99651b_terseLabel_en-US" xlink:label="lab_nx_NonfenestrationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-fenestration</link:label>
    <link:label id="lab_nx_NonfenestrationMember_label_en-US" xlink:label="lab_nx_NonfenestrationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-fenestration [Member]</link:label>
    <link:label id="lab_nx_NonfenestrationMember_documentation_en-US" xlink:label="lab_nx_NonfenestrationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-fenestration [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_NonfenestrationMember" xlink:href="nx-20201031.xsd#nx_NonfenestrationMember"/>
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    <link:label id="lab_srt_SegmentGeographicalDomain_38cb7bfd-86d8-4ca8-b349-622a646b9c26_terseLabel_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Geographical [Domain]</link:label>
    <link:label id="lab_srt_SegmentGeographicalDomain_label_en-US" xlink:label="lab_srt_SegmentGeographicalDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Geographical [Domain]</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_3e15222c-4762-4174-86ce-4a322c4f6ec0_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Settlements</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems_16d99e01-1e27-4cb1-9688-24badd7f8d50_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan Disclosure [Line Items]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="lab_us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FixedIncomeFundsMember_bd170672-3daf-40b7-8068-c195ad11c509_terseLabel_en-US" xlink:label="lab_us-gaap_FixedIncomeFundsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed income</link:label>
    <link:label id="lab_us-gaap_FixedIncomeFundsMember_label_en-US" xlink:label="lab_us-gaap_FixedIncomeFundsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed Income Funds [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeFundsMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FixedIncomeFundsMember"/>
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    <link:label id="lab_us-gaap_RelatedPartyDomain_bc432635-9adb-49a4-890f-de9956400751_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party [Domain]</link:label>
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    <link:label id="lab_us-gaap_CommonStockDividendsPerShareCashPaid_54d84cdc-e254-4af5-a36b-708df7b039b9_verboseLabel_en-US" xlink:label="lab_us-gaap_CommonStockDividendsPerShareCashPaid" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash dividends paid per common share (usd per share)</link:label>
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    <link:label id="lab_us-gaap_OperatingSegmentsMember_562bc2b7-d51a-4a65-8d9b-466aea8b1622_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Segments</link:label>
    <link:label id="lab_us-gaap_OperatingSegmentsMember_label_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Segments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingSegmentsMember" xlink:to="lab_us-gaap_OperatingSegmentsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_96f1f449-26ee-4664-8a98-8e1fe1e9804c_terseLabel_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disaggregation of Revenue [Line Items]</link:label>
    <link:label id="lab_us-gaap_DisaggregationOfRevenueLineItems_label_en-US" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disaggregation of Revenue [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
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    <link:label id="lab_nx_EarningsPerShareDisclosureLineItems_64e803cf-e097-4a80-af45-2288010fcb94_terseLabel_en-US" xlink:label="lab_nx_EarningsPerShareDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share Disclosure [Line Items]</link:label>
    <link:label id="lab_nx_EarningsPerShareDisclosureLineItems_label_en-US" xlink:label="lab_nx_EarningsPerShareDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share Disclosure [Line Items]</link:label>
    <link:label id="lab_nx_EarningsPerShareDisclosureLineItems_documentation_en-US" xlink:label="lab_nx_EarningsPerShareDisclosureLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share Disclosure [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_nx_EarningsPerShareDisclosureLineItems" xlink:href="nx-20201031.xsd#nx_EarningsPerShareDisclosureLineItems"/>
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    <link:label id="lab_us-gaap_ClassOfStockLineItems_07fac489-a0fb-4dc6-b21b-1cc82346d240_terseLabel_en-US" xlink:label="lab_us-gaap_ClassOfStockLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Stock [Line Items]</link:label>
    <link:label id="lab_us-gaap_ClassOfStockLineItems_label_en-US" xlink:label="lab_us-gaap_ClassOfStockLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Stock [Line Items]</link:label>
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    <link:label id="lab_nx_Contributionstargetfundedstatus_d43fb3fb-b58f-48aa-ba9a-f998c18fb52d_terseLabel_en-US" xlink:label="lab_nx_Contributionstargetfundedstatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contributions target funded status</link:label>
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    <link:label id="lab_nx_Contributionstargetfundedstatus_documentation_en-US" xlink:label="lab_nx_Contributionstargetfundedstatus" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Target plan assets of a defined benefit plan, as a percentage of projected benefit obligation.</link:label>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInAccruedLiabilities_4067ad44-2833-4a0a-9b00-13ffe9d5fcb1_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">(Decrease) increase in accrued liabilities</link:label>
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    <link:label id="lab_nx_RelativeTotalShareReturn_60bd66a4-2f62-44d6-bcc2-dbe405e0b6b1_terseLabel_en-US" xlink:label="lab_nx_RelativeTotalShareReturn" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">R-TSR</link:label>
    <link:label id="lab_nx_RelativeTotalShareReturn_label_en-US" xlink:label="lab_nx_RelativeTotalShareReturn" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Relative Total Share Return</link:label>
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    <link:label id="lab_us-gaap_AccountsReceivableGrossCurrent_eab4f079-3586-46d1-85d8-b08a0350d474_totalLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableGrossCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts receivable, gross</link:label>
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    <link:label id="lab_us-gaap_SegmentOperatingActivitiesDomain_e5c65df4-3ea9-412c-9999-5f5364d59cfd_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentOperatingActivitiesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Activities [Domain]</link:label>
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    <link:label id="lab_us-gaap_DeferredTaxAssetsInventory_100d0f40-3426-4b27-9d59-d17a59fdc609_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsInventory" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory</link:label>
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    <link:label id="lab_us-gaap_OperatingLossCarryforwardsValuationAllowance_dc77d3b1-b500-4295-9cd9-02107fbf5f3e_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLossCarryforwardsValuationAllowance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating loss carryforwards, valuation allowance</link:label>
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    <link:label id="lab_us-gaap_InventoryValuationReserves_87ec5e7c-40c3-4350-98eb-e42ee10f0032_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryValuationReserves" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inventory reserves</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalAfterYearFive_a980f1bf-0598-4728-8ac9-bd5a17b69259_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Thereafter</link:label>
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    <link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_a7203144-d8e6-4884-962d-0d48439d7680_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit facility, amount available</link:label>
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