3.20.2 html 749 912 1 true 193 0 false 18 false false R1.htm 100000 - Document - Document and Entity Information Sheet http://www.westrock.com/20200930/taxonomy/role/DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 100010 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS CONSOLIDATED STATEMENTS OF OPERATIONS Statements 2 false false R3.htm 100020 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVELOSSINCOME CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME Statements 3 false false R4.htm 100030 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 4 false false R5.htm 100040 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 5 false false R6.htm 100050 - Statement - CONSOLIDATED STATEMENTS OF EQUITY Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFEQUITY CONSOLIDATED STATEMENTS OF EQUITY Statements 6 false false R7.htm 100060 - Statement - CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFEQUITYParenthetical CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) Statements 7 false false R8.htm 100070 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 8 false false R9.htm 100080 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) Statements 9 false false R10.htm 100090 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical 1) Sheet http://www.westrock.com/20200930/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical1 CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical 1) Statements 10 false false R11.htm 100100 - Disclosure - Description of Business and Summary of Significant Accounting Policies Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies Description of Business and Summary of Significant Accounting Policies Notes 11 false false R12.htm 100110 - Disclosure - Revenue Recognition Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRevenueRecognition Revenue Recognition Notes 12 false false R13.htm 100120 - Disclosure - Acquisitions and Investments Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestments Acquisitions and Investments Notes 13 false false R14.htm 100130 - Disclosure - Restructuring and Other Costs Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCosts Restructuring and Other Costs Notes 14 false false R15.htm 100140 - Disclosure - Retirement Plans Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlans Retirement Plans Notes 15 false false R16.htm 100150 - Disclosure - Income Taxes Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxes Income Taxes Notes 16 false false R17.htm 100160 - Disclosure - Segment Information Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformation Segment Information Notes 17 false false R18.htm 100170 - Disclosure - Interest Expense, Net Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInterestExpenseNet Interest Expense, Net Notes 18 false false R19.htm 100180 - Disclosure - Inventories Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInventories Inventories Notes 19 false false R20.htm 100190 - Disclosure - Property, Plant and Equipment Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosurePropertyPlantAndEquipment Property, Plant and Equipment Notes 20 false false R21.htm 100200 - Disclosure - Other Intangible Assets Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssets Other Intangible Assets Notes 21 false false R22.htm 100210 - Disclosure - Fair Value Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFairValue Fair Value Notes 22 false false R23.htm 100220 - Disclosure - Debt Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDebt Debt Notes 23 false false R24.htm 100230 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantors Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors Notes 24 false false R25.htm 100240 - Disclosure - Leases Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeases Leases Notes 25 false false R26.htm 100250 - Disclosure - Special Purpose Entities Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSpecialPurposeEntities Special Purpose Entities Notes 26 false false R27.htm 100260 - Disclosure - Related Party Transactions Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRelatedPartyTransactions Related Party Transactions Notes 27 false false R28.htm 100270 - Disclosure - Commitments and Contingencies Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 28 false false R29.htm 100280 - Disclosure - Accumulated Other Comprehensive Loss and Other Comprehensive Loss Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLoss Accumulated Other Comprehensive Loss and Other Comprehensive Loss Notes 29 false false R30.htm 100290 - Disclosure - Stockholders' Equity Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureStockholdersEquity Stockholders' Equity Notes 30 false false R31.htm 100300 - Disclosure - Share-Based Compensation Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensation Share-Based Compensation Notes 31 false false R32.htm 100310 - Disclosure - Earnings per Share Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureEarningsPerShare Earnings per Share Notes 32 false false R33.htm 100320 - Disclosure - Financial Results by Quarter (Unaudited) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnaudited Financial Results by Quarter (Unaudited) Notes 33 false false R34.htm 100330 - Disclosure - Description of Business and Summary of Significant Accounting Policies (Policies) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesPolicies Description of Business and Summary of Significant Accounting Policies (Policies) Policies http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies 34 false false R35.htm 100340 - Disclosure - Description of Business and Summary of Significant Accounting Policies (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesTables Description of Business and Summary of Significant Accounting Policies (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPolicies 35 false false R36.htm 100350 - Disclosure - Revenue Recognition (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRevenueRecognitionTables Revenue Recognition (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureRevenueRecognition 36 false false R37.htm 100360 - Disclosure - Acquisitions and Investments (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestmentsTables Acquisitions and Investments (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestments 37 false false R38.htm 100370 - Disclosure - Restructuring and Other Costs (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsTables Restructuring and Other Costs (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCosts 38 false false R39.htm 100380 - Disclosure - Retirement Plans (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansTables Retirement Plans (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlans 39 false false R40.htm 100390 - Disclosure - Income Taxes (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxes 40 false false R41.htm 100400 - Disclosure - Segment Information (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformationTables Segment Information (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformation 41 false false R42.htm 100410 - Disclosure - Interest Expense, Net (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInterestExpenseNetTables Interest Expense, Net (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureInterestExpenseNet 42 false false R43.htm 100420 - Disclosure - Inventories (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInventoriesTables Inventories (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureInventories 43 false false R44.htm 100430 - Disclosure - Property, Plant and Equipment (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosurePropertyPlantAndEquipmentTables Property, Plant and Equipment (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosurePropertyPlantAndEquipment 44 false false R45.htm 100440 - Disclosure - Other Intangible Assets (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssetsTables Other Intangible Assets (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssets 45 false false R46.htm 100450 - Disclosure - Fair Value (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFairValueTables Fair Value (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureFairValue 46 false false R47.htm 100460 - Disclosure - Debt (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDebtTables Debt (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureDebt 47 false false R48.htm 100470 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantorsTables Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantors 48 false false R49.htm 100480 - Disclosure - Leases (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesTables Leases (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureLeases 49 false false R50.htm 100490 - Disclosure - Accumulated Other Comprehensive Loss and Other Comprehensive Loss (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLossTables Accumulated Other Comprehensive Loss and Other Comprehensive Loss (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLoss 50 false false R51.htm 100500 - Disclosure - Share-Based Compensation (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationTables Share-Based Compensation (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensation 51 false false R52.htm 100510 - Disclosure - Earnings per Share (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureEarningsPerShareTables Earnings per Share (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureEarningsPerShare 52 false false R53.htm 100520 - Disclosure - Financial Results by Quarter (Unaudited) (Tables) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnauditedTables Financial Results by Quarter (Unaudited) (Tables) Tables http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnaudited 53 false false R54.htm 100530 - Disclosure - Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) Details 54 false false R55.htm 100540 - Disclosure - Description of Business and Summary of Significant Accounting Policies - Schedule of Valuation and Qualifying Accounts Disclosure (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesScheduleOfValuationAndQualifyingAccountsDisclosureDetails Description of Business and Summary of Significant Accounting Policies - Schedule of Valuation and Qualifying Accounts Disclosure (Details) Details 55 false false R56.htm 100550 - Disclosure - Description of Business and Summary of Significant Accounting Policies - Property, Plant and Equipment, Estimated Useful Lives (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDescriptionOfBusinessAndSummaryOfSignificantAccountingPoliciesPropertyPlantAndEquipmentEstimatedUsefulLivesDetails Description of Business and Summary of Significant Accounting Policies - Property, Plant and Equipment, Estimated Useful Lives (Details) Details 56 false false R57.htm 100560 - Disclosure - Revenue Recognition - Schedule of Disaggregates Revenue by Geographical Market and Product Type (Segment) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRevenueRecognitionScheduleOfDisaggregatesRevenueByGeographicalMarketAndProductTypeSegmentDetails Revenue Recognition - Schedule of Disaggregates Revenue by Geographical Market and Product Type (Segment) (Details) Details 57 false false R58.htm 100570 - Disclosure - Revenue Recognition - Summary of Opening and Closing Balances of Contract Assets and Contract Liabilities (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRevenueRecognitionSummaryOfOpeningAndClosingBalancesOfContractAssetsAndContractLiabilitiesDetails Revenue Recognition - Summary of Opening and Closing Balances of Contract Assets and Contract Liabilities (Details) Details 58 false false R59.htm 100580 - Disclosure - Acquisitions and Investments - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestmentsAdditionalInformationDetails Acquisitions and Investments - Additional Information (Details) Details 59 false false R60.htm 100590 - Disclosure - Acquisitions and Investments - Summary of Fair Values of Assets Acquired and Liabilities Assumed by Major Class of Assets and Liabilities and Measurement Period Adjustments (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestmentsSummaryOfFairValuesOfAssetsAcquiredAndLiabilitiesAssumedByMajorClassOfAssetsAndLiabilitiesAndMeasurementPeriodAdjustmentsDetails Acquisitions and Investments - Summary of Fair Values of Assets Acquired and Liabilities Assumed by Major Class of Assets and Liabilities and Measurement Period Adjustments (Details) Details 60 false false R61.htm 100600 - Disclosure - Acquisitions and Investments - Summary of Weighted Average Life and Fair Value of Intangible Asset Recognized in KapStone Acquisition, Excluding Goodwill (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAcquisitionsAndInvestmentsSummaryOfWeightedAverageLifeAndFairValueOfIntangibleAssetRecognizedInKapstoneAcquisitionExcludingGoodwillDetails Acquisitions and Investments - Summary of Weighted Average Life and Fair Value of Intangible Asset Recognized in KapStone Acquisition, Excluding Goodwill (Details) Details 61 false false R62.htm 100610 - Disclosure - Restructuring and Other Costs - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsAdditionalInformationDetails Restructuring and Other Costs - Additional Information (Details) Details 62 false false R63.htm 100620 - Disclosure - Restructuring and Other Costs - Schedule of Restructuring and Other Costs (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsScheduleOfRestructuringAndOtherCostsDetails Restructuring and Other Costs - Schedule of Restructuring and Other Costs (Details) Details 63 false false R64.htm 100630 - Disclosure - Restructuring and Other Costs - Schedule of Restructuring Charges Related to Active Restructuring Initiatives (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsScheduleOfRestructuringChargesRelatedToActiveRestructuringInitiativesDetails Restructuring and Other Costs - Schedule of Restructuring Charges Related to Active Restructuring Initiatives (Details) Details 64 false false R65.htm 100640 - Disclosure - Restructuring and Other Costs - Schedule of Acquisition, Divestiture and Integration Costs (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsScheduleOfAcquisitionDivestitureAndIntegrationCostsDetails Restructuring and Other Costs - Schedule of Acquisition, Divestiture and Integration Costs (Details) Details 65 false false R66.htm 100650 - Disclosure - Restructuring and Other Costs - Schedule of Changes in Restructuring Accrual Charges (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsScheduleOfChangesInRestructuringAccrualChargesDetails Restructuring and Other Costs - Schedule of Changes in Restructuring Accrual Charges (Details) Details 66 false false R67.htm 100660 - Disclosure - Restructuring and Other Costs - Schedule of Reconciliation of Accruals and Charges (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRestructuringAndOtherCostsScheduleOfReconciliationOfAccrualsAndChargesDetails Restructuring and Other Costs - Schedule of Reconciliation of Accruals and Charges (Details) Details 67 false false R68.htm 100670 - Disclosure - Retirement Plans - Schedule of Allocation of Plan Assets - (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfAllocationOfPlanAssetsDetails Retirement Plans - Schedule of Allocation of Plan Assets - (Details) Details 68 false false R69.htm 100680 - Disclosure - Retirement Plans - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansAdditionalInformationDetails Retirement Plans - Additional Information (Details) Details 69 false false R70.htm 100690 - Disclosure - Retirement Plans - Schedule of Weighted-Average Assumptions Used to Measure Benefit Plan Obligations (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfWeightedAverageAssumptionsUsedToMeasureBenefitPlanObligationsDetails Retirement Plans - Schedule of Weighted-Average Assumptions Used to Measure Benefit Plan Obligations (Details) Details 70 false false R71.htm 100700 - Disclosure - Retirement Plans - Schedule of Changes in Benefit Obligations (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfChangesInBenefitObligationsDetails Retirement Plans - Schedule of Changes in Benefit Obligations (Details) Details 71 false false R72.htm 100710 - Disclosure - Retirement Plans - Schedule of Amounts in Accumulated Other Comprehensive (Income) Loss (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossDetails Retirement Plans - Schedule of Amounts in Accumulated Other Comprehensive (Income) Loss (Details) Details 72 false false R73.htm 100720 - Disclosure - Retirement Plans - Schedule of Amounts Recognized in Other Comprehensive Loss (Income) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfAmountsRecognizedInOtherComprehensiveLossIncomeDetails Retirement Plans - Schedule of Amounts Recognized in Other Comprehensive Loss (Income) (Details) Details 73 false false R74.htm 100730 - Disclosure - Retirement Plans - Summary of Components of Net Pension Income and Summary of Components of Postretirement Benefit Cost (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansSummaryOfComponentsOfNetPensionIncomeAndSummaryOfComponentsOfPostretirementBenefitCostDetails Retirement Plans - Summary of Components of Net Pension Income and Summary of Components of Postretirement Benefit Cost (Details) Details 74 false false R75.htm 100750 - Disclosure - Retirement Plans - Schedule of Weighted-Average Assumptions Used in Calculation of Benefit Plan Expense (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfWeightedAverageAssumptionsUsedInCalculationOfBenefitPlanExpenseDetails Retirement Plans - Schedule of Weighted-Average Assumptions Used in Calculation of Benefit Plan Expense (Details) Details 75 false false R76.htm 100760 - Disclosure - Retirement Plans - Schedule of Estimated Losses Gains Amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfEstimatedLossesGainsAmortizedFromAccumulatedOtherComprehensiveLossIntoNetPeriodicBenefitCostDetails Retirement Plans - Schedule of Estimated Losses Gains Amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost (Details) Details 76 false false R77.htm 100770 - Disclosure - Retirement Plans - Schedule of Estimated Benefit Payments (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfEstimatedBenefitPaymentsDetails Retirement Plans - Schedule of Estimated Benefit Payments (Details) Details 77 false false R78.htm 100780 - Disclosure - Retirement Plans - Summary of Pension Plan Assets Measured at Fair Value on Recurring Basis (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansSummaryOfPensionPlanAssetsMeasuredAtFairValueOnRecurringBasisDetails Retirement Plans - Summary of Pension Plan Assets Measured at Fair Value on Recurring Basis (Details) Details 78 false false R79.htm 100790 - Disclosure - Retirement Plans - Summary of Pension Plan Assets Measured at Fair Value on Recurring Basis (Parenthetical) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansSummaryOfPensionPlanAssetsMeasuredAtFairValueOnRecurringBasisParentheticalDetails Retirement Plans - Summary of Pension Plan Assets Measured at Fair Value on Recurring Basis (Parenthetical) (Details) Details 79 false false R80.htm 100800 - Disclosure - Retirement Plans - Summary of Assets Measured at Fair Value Based on NAV Per Share (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansSummaryOfAssetsMeasuredAtFairValueBasedOnNAVPerShareDetails Retirement Plans - Summary of Assets Measured at Fair Value Based on NAV Per Share (Details) Details 80 false false R81.htm 100810 - Disclosure - Retirement Plans - Schedule of Health Care Cost Trend Rates (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRetirementPlansScheduleOfHealthCareCostTrendRatesDetails Retirement Plans - Schedule of Health Care Cost Trend Rates (Details) Details 81 false false R82.htm 100820 - Disclosure - Income Taxes (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesDetails Income Taxes (Details) Details http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesTables 82 false false R83.htm 100830 - Disclosure - Income Taxes - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails Income Taxes - Additional Information (Details) Details 83 false false R84.htm 100840 - Disclosure - Income Taxes Effective Tax Rate Reconciliation (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesEffectiveTaxRateReconciliationDetails Income Taxes Effective Tax Rate Reconciliation (Details) Details 84 false false R85.htm 100850 - Disclosure - Income Taxes Effective Tax Rate Reconciliation (Parenthetical) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesEffectiveTaxRateReconciliationParentheticalDetails Income Taxes Effective Tax Rate Reconciliation (Parenthetical) (Details) Details 85 false false R86.htm 100860 - Disclosure - Income Taxes Deferred Taxes (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesDeferredTaxesDetails Income Taxes Deferred Taxes (Details) Details 86 false false R87.htm 100880 - Disclosure - Income Taxes Valuation Allowance Against Deferred Tax Assets (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesValuationAllowanceAgainstDeferredTaxAssetsDetails Income Taxes Valuation Allowance Against Deferred Tax Assets (Details) Details 87 false false R88.htm 100890 - Disclosure - Income Taxes Unrecognized Tax Benefit (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureIncomeTaxesUnrecognizedTaxBenefitDetails Income Taxes Unrecognized Tax Benefit (Details) Details 88 false false R89.htm 100900 - Disclosure - Segment Information - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformationAdditionalInformationDetails Segment Information - Additional Information (Details) Details 89 false false R90.htm 100910 - Disclosure - Segment Information - Schedule of Revenue from External Customers, Segment Income and Long-Lived Assets, by Geographical Areas (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformationScheduleOfRevenueFromExternalCustomersSegmentIncomeAndLongLivedAssetsByGeographicalAreasDetails Segment Information - Schedule of Revenue from External Customers, Segment Income and Long-Lived Assets, by Geographical Areas (Details) Details 90 false false R91.htm 100920 - Disclosure - Segment Information - Certain Operating Data for Segments (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformationCertainOperatingDataForSegmentsDetails Segment Information - Certain Operating Data for Segments (Details) Details 91 false false R92.htm 100930 - Disclosure - Segment Information - Changes in Carrying Amount of Goodwill (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSegmentInformationChangesInCarryingAmountOfGoodwillDetails Segment Information - Changes in Carrying Amount of Goodwill (Details) Details 92 false false R93.htm 100940 - Disclosure - Interest Expense, Net - Summary of Components of Interest Expense, Net (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInterestExpenseNetSummaryOfComponentsOfInterestExpenseNetDetails Interest Expense, Net - Summary of Components of Interest Expense, Net (Details) Details 93 false false R94.htm 100950 - Disclosure - Inventories - Schedule of Inventories (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureInventoriesScheduleOfInventoriesDetails Inventories - Schedule of Inventories (Details) Details 94 false false R95.htm 100960 - Disclosure - Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosurePropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) Details 95 false false R96.htm 100970 - Disclosure - Property, Plant and Equipment - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosurePropertyPlantAndEquipmentAdditionalInformationDetails Property, Plant and Equipment - Additional Information (Details) Details 96 false false R97.htm 100980 - Disclosure - Other Intangible Assets - Schedule of Finite-Lived Intangible Assets (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssetsScheduleOfFiniteLivedIntangibleAssetsDetails Other Intangible Assets - Schedule of Finite-Lived Intangible Assets (Details) Details 97 false false R98.htm 100990 - Disclosure - Other Intangible Assets - Estimated Intangible Asset Future Amortization Expense (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssetsEstimatedIntangibleAssetFutureAmortizationExpenseDetails Other Intangible Assets - Estimated Intangible Asset Future Amortization Expense (Details) Details 98 false false R99.htm 101000 - Disclosure - Other Intangible Assets - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureOtherIntangibleAssetsAdditionalInformationDetails Other Intangible Assets - Additional Information (Details) Details 99 false false R100.htm 101010 - Disclosure - Fair Value - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFairValueAdditionalInformationDetails Fair Value - Additional Information (Details) Details 100 false false R101.htm 101020 - Disclosure - Fair Value - Summary of Activity Under A/R Sales Agreement (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFairValueSummaryOfActivityUnderARSalesAgreementDetails Fair Value - Summary of Activity Under A/R Sales Agreement (Details) Details 101 false false R102.htm 101030 - Disclosure - Debt - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDebtAdditionalInformationDetails Debt - Additional Information (Details) Details 102 false false R103.htm 101040 - Disclosure - Debt - Schedule of Carrying Value and Weighted Average Interest Rate of Individual Components of Debt (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDebtScheduleOfCarryingValueAndWeightedAverageInterestRateOfIndividualComponentsOfDebtDetails Debt - Schedule of Carrying Value and Weighted Average Interest Rate of Individual Components of Debt (Details) Details 103 false false R104.htm 101050 - Disclosure - Debt - Schedule of Aggregate Maturities of Debt (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureDebtScheduleOfAggregateMaturitiesOfDebtDetails Debt - Schedule of Aggregate Maturities of Debt (Details) Details 104 false false R105.htm 101060 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Operations (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantorsCondensedConsolidatingStatementsOfOperationsDetails Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Operations (Details) Details 105 false false R106.htm 101080 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Balance Sheets (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantorsCondensedConsolidatingBalanceSheetsDetails Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Balance Sheets (Details) Details 106 false false R107.htm 101090 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Cash Flows (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantorsCondensedConsolidatingStatementsOfCashFlowsDetails Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Condensed Consolidating Statements of Cash Flows (Details) Details 107 false false R108.htm 101100 - Disclosure - Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Noncash Operating, Investing and Financing Activities (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSelectedCondensedConsolidatingFinancialStatementsOfParentIssuerGuarantorsAndNonGuarantorsNoncashOperatingInvestingAndFinancingActivitiesDetails Selected Condensed Consolidating Financial Statements of Parent, Issuer, Guarantors and Non-Guarantors - Noncash Operating, Investing and Financing Activities (Details) Details 108 false false R109.htm 101110 - Disclosure - Leases - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesAdditionalInformationDetails Leases - Additional Information (Details) Details 109 false false R110.htm 101120 - Disclosure - Leases - Schedule of Components of Lease Costs (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesScheduleOfComponentsOfLeaseCostsDetails Leases - Schedule of Components of Lease Costs (Details) Details 110 false false R111.htm 101130 - Disclosure - Leases - Summary of Supplemental Balance Sheet Information Related to Leases (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesSummaryOfSupplementalBalanceSheetInformationRelatedToLeasesDetails Leases - Summary of Supplemental Balance Sheet Information Related to Leases (Details) Details 111 false false R112.htm 101140 - Disclosure - Leases - Summary of Lease Term and Discount Rate (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesSummaryOfLeaseTermAndDiscountRateDetails Leases - Summary of Lease Term and Discount Rate (Details) Details 112 false false R113.htm 101150 - Disclosure - Leases - Summary of Supplemental Cash Flow Information Related to Leases (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesSummaryOfSupplementalCashFlowInformationRelatedToLeasesDetails Leases - Summary of Supplemental Cash Flow Information Related to Leases (Details) Details 113 false false R114.htm 101160 - Disclosure - Leases - Summary of Maturity of Lease Liabilities (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesSummaryOfMaturityOfLeaseLiabilitiesDetails Leases - Summary of Maturity of Lease Liabilities (Details) Details 114 false false R115.htm 101180 - Disclosure - Leases - Summary of Future Minimum Lease Payments Under All Noncancelable Operating Leases (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureLeasesSummaryOfFutureMinimumLeasePaymentsUnderAllNoncancelableOperatingLeasesDetails Leases - Summary of Future Minimum Lease Payments Under All Noncancelable Operating Leases (Details) Details 115 false false R116.htm 101190 - Disclosure - Special Purpose Entities (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureSpecialPurposeEntitiesDetails Special Purpose Entities (Details) Details http://www.westrock.com/20200930/taxonomy/role/DisclosureSpecialPurposeEntities 116 false false R117.htm 101200 - Disclosure - Related Party Transactions - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureRelatedPartyTransactionsAdditionalInformationDetails Related Party Transactions - Additional Information (Details) Details 117 false false R118.htm 101210 - Disclosure - Commitments and Contingencies - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails Commitments and Contingencies - Additional Information (Details) Details 118 false false R119.htm 101220 - Disclosure - Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Schedule of Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLossScheduleOfChangesInAccumulatedOtherComprehensiveLossNetOfTaxDetails Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Schedule of Changes in Accumulated Other Comprehensive Loss, Net of Tax (Details) Details 119 false false R120.htm 101230 - Disclosure - Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Summary of Reclassification out of Accumulated Other Comprehensive Loss (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLossSummaryOfReclassificationOutOfAccumulatedOtherComprehensiveLossDetails Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Summary of Reclassification out of Accumulated Other Comprehensive Loss (Details) Details 120 false false R121.htm 101240 - Disclosure - Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Schedule of Other Comprehensive (Loss) Income (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureAccumulatedOtherComprehensiveLossAndOtherComprehensiveLossScheduleOfOtherComprehensiveLossIncomeDetails Accumulated Other Comprehensive Loss and Other Comprehensive Loss - Schedule of Other Comprehensive (Loss) Income (Details) Details 121 false false R122.htm 101270 - Disclosure - Stockholders' Equity - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetails Stockholders' Equity - Additional Information (Details) Details 122 false false R123.htm 101280 - Disclosure - Share-Based Compensation - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationAdditionalInformationDetails Share-Based Compensation - Additional Information (Details) Details 123 false false R124.htm 101290 - Disclosure - Share-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsDetails Share-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Details) Details 124 false false R125.htm 101300 - Disclosure - Share-Based Compensation - Summary of Changes in Stock Options (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfChangesInStockOptionsDetails Share-Based Compensation - Summary of Changes in Stock Options (Details) Details 125 false false R126.htm 101310 - Disclosure - Share-Based Compensation - Summary of Changes in SARs (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfChangesInSarsDetails Share-Based Compensation - Summary of Changes in SARs (Details) Details 126 false false R127.htm 101320 - Disclosure - Share-Based Compensation - Restricted Stock - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationRestrictedStockAdditionalInformationDetails Share-Based Compensation - Restricted Stock - Additional Information (Details) Details 127 false false R128.htm 101330 - Disclosure - Share-Based Compensation - Summary of Changes in Unvested Restricted Stock (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfChangesInUnvestedRestrictedStockDetails Share-Based Compensation - Summary of Changes in Unvested Restricted Stock (Details) Details 128 false false R129.htm 101340 - Disclosure - Share-Based Compensation - Summary of Changes in Unvested Restricted Stock (Parenthetical) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfChangesInUnvestedRestrictedStockParentheticalDetails Share-Based Compensation - Summary of Changes in Unvested Restricted Stock (Parenthetical) (Details) Details 129 false false R130.htm 101350 - Disclosure - Share-Based Compensation - Summary of Restricted Stock Shares Granted (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfRestrictedStockSharesGrantedDetails Share-Based Compensation - Summary of Restricted Stock Shares Granted (Details) Details 130 false false R131.htm 101360 - Disclosure - Share-Based Compensation - Summary of Restricted Stock Shares Granted (Parenthetical) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfRestrictedStockSharesGrantedParentheticalDetails Share-Based Compensation - Summary of Restricted Stock Shares Granted (Parenthetical) (Details) Details 131 false false R132.htm 101370 - Disclosure - Share-Based Compensation - Summary of Restricted Stock Awards - Vested, Granted and Changes (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationSummaryOfRestrictedStockAwardsVestedGrantedAndChangesDetails Share-Based Compensation - Summary of Restricted Stock Awards - Vested, Granted and Changes (Details) Details 132 false false R133.htm 101380 - Disclosure - Share-Based Compensation - Employee Stock Purchase Plan - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureShareBasedCompensationEmployeeStockPurchasePlanAdditionalInformationDetails Share-Based Compensation - Employee Stock Purchase Plan - Additional Information (Details) Details 133 false false R134.htm 101390 - Disclosure - Earnings per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureEarningsPerShareScheduleOfEarningsPerShareBasicAndDilutedDetails Earnings per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) Details 134 false false R135.htm 101400 - Disclosure - Earnings per Share - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureEarningsPerShareAdditionalInformationDetails Earnings per Share - Additional Information (Details) Details 135 false false R136.htm 101410 - Disclosure - Financial Results by Quarter (Unaudited) (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnauditedDetails Financial Results by Quarter (Unaudited) (Details) Details http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnauditedTables 136 false false R137.htm 101420 - Disclosure - Financial Results by Quarter (Unaudited) - Additional Information (Details) Sheet http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnauditedAdditionalInformationDetails Financial Results by Quarter (Unaudited) - Additional Information (Details) Details http://www.westrock.com/20200930/taxonomy/role/DisclosureFinancialResultsByQuarterUnauditedTables 137 false false All Reports Book All Reports wrk-10k_20200930.htm wrk-20200930.xsd wrk-20200930_cal.xml wrk-20200930_def.xml wrk-20200930_lab.xml wrk-20200930_pre.xml wrk-ex1041b_316.htm wrk-ex1044_149.htm wrk-ex21_13.htm wrk-ex23_10.htm wrk-ex311_8.htm wrk-ex312_7.htm wrk-ex321_12.htm http://fasb.org/srt/2019-01-31 http://xbrl.sec.gov/dei/2019-01-31 http://xbrl.sec.gov/country/2017-01-31 http://fasb.org/us-gaap/2019-01-31 true true