3.26.1 html 157 223 1 true 36 0 false 5 false false R1.htm 0000001 - Document - Document And Entity Information Sheet http://www.newmarket.com/role/DocumentAndEntityInformation Document And Entity Information Cover 1 false false R2.htm 9952151 - Statement - Consolidated Statements Of Income Sheet http://www.newmarket.com/role/ConsolidatedStatementsOfIncome Consolidated Statements Of Income Statements 2 false false R3.htm 9952152 - Statement - Consolidated Statements Of Comprehensive Income Sheet http://www.newmarket.com/role/ConsolidatedStatementsOfComprehensiveIncome Consolidated Statements Of Comprehensive Income Statements 3 false false R4.htm 9952153 - Statement - Consolidated Statements Of Comprehensive Income (Parenthetical) Sheet http://www.newmarket.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical Consolidated Statements Of Comprehensive Income (Parenthetical) Statements 4 false false R5.htm 9952154 - Statement - Condensed Consolidated Balance Sheets Sheet http://www.newmarket.com/role/CondensedConsolidatedBalanceSheets Condensed Consolidated Balance Sheets Statements 5 false false R6.htm 9952155 - Statement - Condensed Consolidated Balance Sheets (Parenthetical) Sheet http://www.newmarket.com/role/CondensedConsolidatedBalanceSheetsParenthetical Condensed Consolidated Balance Sheets (Parenthetical) Statements 6 false false R7.htm 9952156 - Statement - Consolidated Statements Of Shareholders' Equity Sheet http://www.newmarket.com/role/ConsolidatedStatementsOfShareholdersEquity Consolidated Statements Of Shareholders' Equity Statements 7 false false R8.htm 9952157 - Statement - Consolidated Statements Of Shareholders' Equity (Parenthetical) Sheet http://www.newmarket.com/role/ConsolidatedStatementsOfShareholdersEquityParenthetical Consolidated Statements Of Shareholders' Equity (Parenthetical) Statements 8 false false R9.htm 9952158 - Statement - Condensed Consolidated Statements Of Cash Flows Sheet http://www.newmarket.com/role/CondensedConsolidatedStatementsOfCashFlows Condensed Consolidated Statements Of Cash Flows Statements 9 false false R10.htm 9952159 - Statement - Condensed Consolidated Statements of Cash Flows (Parenthetical) Sheet http://www.newmarket.com/role/CondensedConsolidatedStatementsofCashFlowsParenthetical Condensed Consolidated Statements of Cash Flows (Parenthetical) Statements 10 false false R11.htm 9952160 - Disclosure - Financial Statement Presentation Sheet http://www.newmarket.com/role/FinancialStatementPresentation Financial Statement Presentation Notes 11 false false R12.htm 9952161 - Disclosure - Acquisition of Business Sheet http://www.newmarket.com/role/AcquisitionofBusiness Acquisition of Business Notes 12 false false R13.htm 9952162 - Disclosure - Net Sales Sheet http://www.newmarket.com/role/NetSales Net Sales Notes 13 false false R14.htm 9952163 - Disclosure - Segment Information Sheet http://www.newmarket.com/role/SegmentInformation Segment Information Notes 14 false false R15.htm 9952164 - Disclosure - Pension Plans and Other Postretirement Benefits Sheet http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefits Pension Plans and Other Postretirement Benefits Notes 15 false false R16.htm 9952165 - Disclosure - Earnings Per Share Sheet http://www.newmarket.com/role/EarningsPerShare Earnings Per Share Notes 16 false false R17.htm 9952166 - Disclosure - Inventories Sheet http://www.newmarket.com/role/Inventories Inventories Notes 17 false false R18.htm 9952167 - Disclosure - Intangibles (Net of Amortization) and Goodwill Sheet http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwill Intangibles (Net of Amortization) and Goodwill Notes 18 false false R19.htm 9952168 - Disclosure - Long-term Debt Sheet http://www.newmarket.com/role/LongtermDebt Long-term Debt Notes 19 false false R20.htm 9952169 - Disclosure - Commitments and Contingencies Sheet http://www.newmarket.com/role/CommitmentsandContingencies Commitments and Contingencies Notes 20 false false R21.htm 9952170 - Disclosure - Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss Sheet http://www.newmarket.com/role/OtherComprehensiveIncomeLossandAccumulatedOtherComprehensiveLoss Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss Notes 21 false false R22.htm 9952171 - Disclosure - Fair Value Measurements Sheet http://www.newmarket.com/role/FairValueMeasurements Fair Value Measurements Notes 22 false false R23.htm 9952172 - Disclosure - Recent Accounting Pronouncements Sheet http://www.newmarket.com/role/RecentAccountingPronouncements Recent Accounting Pronouncements Notes 23 false false R24.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 24 false false R25.htm 9955511 - Disclosure - Significant Accounting Policies (Policies) Sheet http://www.newmarket.com/role/SignificantAccountingPoliciesPolicies Significant Accounting Policies (Policies) Policies http://www.newmarket.com/role/RecentAccountingPronouncements 25 false false R26.htm 9955512 - Disclosure - Acquisition of Business (Tables) Sheet http://www.newmarket.com/role/AcquisitionofBusinessTables Acquisition of Business (Tables) Tables http://www.newmarket.com/role/AcquisitionofBusiness 26 false false R27.htm 9955513 - Disclosure - Net Sales (Tables) Sheet http://www.newmarket.com/role/NetSalesTables Net Sales (Tables) Tables http://www.newmarket.com/role/NetSales 27 false false R28.htm 9955514 - Disclosure - Segment Information (Tables) Sheet http://www.newmarket.com/role/SegmentInformationTables Segment Information (Tables) Tables http://www.newmarket.com/role/SegmentInformation 28 false false R29.htm 9955515 - Disclosure - Pension Plans and Other Postretirement Benefits (Tables) Sheet http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefitsTables Pension Plans and Other Postretirement Benefits (Tables) Tables http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefits 29 false false R30.htm 9955516 - Disclosure - Earnings Per Share (Tables) Sheet http://www.newmarket.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://www.newmarket.com/role/EarningsPerShare 30 false false R31.htm 9955517 - Disclosure - Inventories (Tables) Sheet http://www.newmarket.com/role/InventoriesTables Inventories (Tables) Tables http://www.newmarket.com/role/Inventories 31 false false R32.htm 9955518 - Disclosure - Intangibles (Net of Amortization) and Goodwill (Tables) Sheet http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillTables Intangibles (Net of Amortization) and Goodwill (Tables) Tables http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwill 32 false false R33.htm 9955519 - Disclosure - Long-term Debt (Tables) Sheet http://www.newmarket.com/role/LongtermDebtTables Long-term Debt (Tables) Tables http://www.newmarket.com/role/LongtermDebt 33 false false R34.htm 9955520 - Disclosure - Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss (Tables) Sheet http://www.newmarket.com/role/OtherComprehensiveIncomeLossandAccumulatedOtherComprehensiveLossTables Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss (Tables) Tables http://www.newmarket.com/role/OtherComprehensiveIncomeLossandAccumulatedOtherComprehensiveLoss 34 false false R35.htm 9955521 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.newmarket.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.newmarket.com/role/FairValueMeasurements 35 false false R36.htm 9955523 - Disclosure - Acquisition of Business (Narrative) (Details) Sheet http://www.newmarket.com/role/AcquisitionofBusinessNarrativeDetails Acquisition of Business (Narrative) (Details) Details http://www.newmarket.com/role/AcquisitionofBusinessTables 36 false false R37.htm 9955524 - Disclosure - Acquisition of Business (Fair Values of Assets and Liabilities Assumed) (Details) Sheet http://www.newmarket.com/role/AcquisitionofBusinessFairValuesofAssetsandLiabilitiesAssumedDetails Acquisition of Business (Fair Values of Assets and Liabilities Assumed) (Details) Details http://www.newmarket.com/role/AcquisitionofBusinessTables 37 false false R38.htm 9955525 - Disclosure - Acquisition of Business (Schedule of Intangibles) (Details) Sheet http://www.newmarket.com/role/AcquisitionofBusinessScheduleofIntangiblesDetails Acquisition of Business (Schedule of Intangibles) (Details) Details http://www.newmarket.com/role/AcquisitionofBusinessTables 38 false false R39.htm 9955526 - Disclosure - Net Sales (Schedule of Net Sales by Geographical Area) (Details) Sheet http://www.newmarket.com/role/NetSalesScheduleofNetSalesbyGeographicalAreaDetails Net Sales (Schedule of Net Sales by Geographical Area) (Details) Details http://www.newmarket.com/role/NetSalesTables 39 false false R40.htm 9955527 - Disclosure - Segment Information (Narrative) (Details) Sheet http://www.newmarket.com/role/SegmentInformationNarrativeDetails Segment Information (Narrative) (Details) Details http://www.newmarket.com/role/SegmentInformationTables 40 false false R41.htm 9955528 - Disclosure - Segment Information (Schedule Of Net Sales And Operating Profit By Segment) (Details) Sheet http://www.newmarket.com/role/SegmentInformationScheduleOfNetSalesAndOperatingProfitBySegmentDetails Segment Information (Schedule Of Net Sales And Operating Profit By Segment) (Details) Details http://www.newmarket.com/role/SegmentInformationTables 41 false false R42.htm 9955529 - Disclosure - Schedule of Additions to Long-lived Assets and Depreciation and Amortization (Details) Sheet http://www.newmarket.com/role/ScheduleofAdditionstoLonglivedAssetsandDepreciationandAmortizationDetails Schedule of Additions to Long-lived Assets and Depreciation and Amortization (Details) Details 42 false false R43.htm 9955530 - Disclosure - Pension Plans and Other Postretirement Benefits (Cash Contributions Made And Expected Remaining Contributions For Pension And Postretirement Benefit Plans) (Details) Sheet http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefitsCashContributionsMadeAndExpectedRemainingContributionsForPensionAndPostretirementBenefitPlansDetails Pension Plans and Other Postretirement Benefits (Cash Contributions Made And Expected Remaining Contributions For Pension And Postretirement Benefit Plans) (Details) Details http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefitsTables 43 false false R44.htm 9955531 - Disclosure - Pension Plans and Other Postretirement Benefits (Net Periodic Benefit Cost (Income) For Pension And Postretirement Benefit Plans) (Details) Sheet http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefitsNetPeriodicBenefitCostIncomeForPensionAndPostretirementBenefitPlansDetails Pension Plans and Other Postretirement Benefits (Net Periodic Benefit Cost (Income) For Pension And Postretirement Benefit Plans) (Details) Details http://www.newmarket.com/role/PensionPlansandOtherPostretirementBenefitsTables 44 false false R45.htm 9955532 - Disclosure - Earnings Per Share (Details) Sheet http://www.newmarket.com/role/EarningsPerShareDetails Earnings Per Share (Details) Details http://www.newmarket.com/role/EarningsPerShareTables 45 false false R46.htm 9955533 - Disclosure - Inventories (Schedule of Inventories) (Details) Sheet http://www.newmarket.com/role/InventoriesScheduleofInventoriesDetails Inventories (Schedule of Inventories) (Details) Details http://www.newmarket.com/role/InventoriesTables 46 false false R47.htm 9955534 - Disclosure - Intangibles (Net of Amortization) and Goodwill (Narrative) (Details) Sheet http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillNarrativeDetails Intangibles (Net of Amortization) and Goodwill (Narrative) (Details) Details http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillTables 47 false false R48.htm 9955535 - Disclosure - Intangibles (Net of Amortization) and Goodwill (Schedule Of Information Related To Intangible Assets and Goodwill) (Details) Sheet http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillScheduleOfInformationRelatedToIntangibleAssetsandGoodwillDetails Intangibles (Net of Amortization) and Goodwill (Schedule Of Information Related To Intangible Assets and Goodwill) (Details) Details http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillTables 48 false false R49.htm 9955536 - Disclosure - Intangibles (Net of Amortization) and Goodwill (Schedule Of Amortization Expense And Estimated Annual Amortization Expense Related To Intangible Assets) (Details) Sheet http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillScheduleOfAmortizationExpenseAndEstimatedAnnualAmortizationExpenseRelatedToIntangibleAssetsDetails Intangibles (Net of Amortization) and Goodwill (Schedule Of Amortization Expense And Estimated Annual Amortization Expense Related To Intangible Assets) (Details) Details http://www.newmarket.com/role/IntangiblesNetofAmortizationandGoodwillTables 49 false false R50.htm 9955537 - Disclosure - Long-term Debt (Schedule Of Long-Term Debt) (Details) Sheet http://www.newmarket.com/role/LongtermDebtScheduleOfLongTermDebtDetails Long-term Debt (Schedule Of Long-Term Debt) (Details) Details http://www.newmarket.com/role/LongtermDebtTables 50 false false R51.htm 9955538 - Disclosure - Long-term Debt (Narrative) (Details) Sheet http://www.newmarket.com/role/LongtermDebtNarrativeDetails Long-term Debt (Narrative) (Details) Details http://www.newmarket.com/role/LongtermDebtTables 51 false false R52.htm 9955539 - Disclosure - Commitments and Contingencies (Environmental) (Details) Sheet http://www.newmarket.com/role/CommitmentsandContingenciesEnvironmentalDetails Commitments and Contingencies (Environmental) (Details) Details http://www.newmarket.com/role/CommitmentsandContingencies 52 false false R53.htm 9955540 - Disclosure - Commitment and Contingencies (Other Commitments) (Details) Sheet http://www.newmarket.com/role/CommitmentandContingenciesOtherCommitmentsDetails Commitment and Contingencies (Other Commitments) (Details) Details 53 false false R54.htm 9955541 - Disclosure - Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss (Schedule of Components of Accumulated Other Comprehensive Loss) (Details) Sheet http://www.newmarket.com/role/OtherComprehensiveIncomeLossandAccumulatedOtherComprehensiveLossScheduleofComponentsofAccumulatedOtherComprehensiveLossDetails Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Loss (Schedule of Components of Accumulated Other Comprehensive Loss) (Details) Details http://www.newmarket.com/role/OtherComprehensiveIncomeLossandAccumulatedOtherComprehensiveLossTables 54 false false R55.htm 9955542 - Disclosure - Fair Value Measurements (Narrative) (Details) Sheet http://www.newmarket.com/role/FairValueMeasurementsNarrativeDetails Fair Value Measurements (Narrative) (Details) Details http://www.newmarket.com/role/FairValueMeasurementsTables 55 false false R56.htm 9955543 - Disclosure - Fair Value Measurements (Estimated Fair Value Of Long-Term Debt) (Details) Sheet http://www.newmarket.com/role/FairValueMeasurementsEstimatedFairValueOfLongTermDebtDetails Fair Value Measurements (Estimated Fair Value Of Long-Term Debt) (Details) Details http://www.newmarket.com/role/FairValueMeasurementsTables 56 false false All Reports Book All Reports neu-20260630.htm neu-20260630.xsd neu-20260630_cal.xml neu-20260630_def.xml neu-20260630_lab.xml neu-20260630_pre.xml http://fasb.org/us-gaap/2026 http://xbrl.sec.gov/dei/2026 http://xbrl.sec.gov/ecd/2026 true true