3.26.1 html 128 98 1 true 16 0 false 4 false false R1.htm 0000001 - Document - Cover Sheet http://www.commercebank.com/role/Cover Cover Cover 1 false false R2.htm 0000002 - Statement - Employee Benefit Plan, Statement of Net Asset Available for Benefit (Statement) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanStatementofNetAssetAvailableforBenefitStatement Employee Benefit Plan, Statement of Net Asset Available for Benefit (Statement) Statements 2 false false R3.htm 0000003 - Statement - Employee Benefit Plan, Statement of Change in Net Asset Available for Benefit (Statement) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanStatementofChangeinNetAssetAvailableforBenefitStatement Employee Benefit Plan, Statement of Change in Net Asset Available for Benefit (Statement) Statements 3 false false R4.htm 0000004 - Disclosure - Employee Benefit Plan, Description of Plan Sheet http://www.commercebank.com/role/EmployeeBenefitPlanDescriptionofPlan Employee Benefit Plan, Description of Plan Notes 4 false false R5.htm 0000005 - Disclosure - Employee Benefit Plan, Summary of Accounting Policy Sheet http://www.commercebank.com/role/EmployeeBenefitPlanSummaryofAccountingPolicy Employee Benefit Plan, Summary of Accounting Policy Notes 5 false false R6.htm 0000006 - Disclosure - Employee Benefit Plan, Risk and Uncertainty Sheet http://www.commercebank.com/role/EmployeeBenefitPlanRiskandUncertainty Employee Benefit Plan, Risk and Uncertainty Notes 6 false false R7.htm 0000007 - Disclosure - Company Stock Fund Sheet http://www.commercebank.com/role/CompanyStockFund Company Stock Fund Notes 7 false false R8.htm 0000008 - Disclosure - Employee Benefit Plan, Tax Status Sheet http://www.commercebank.com/role/EmployeeBenefitPlanTaxStatus Employee Benefit Plan, Tax Status Notes 8 false false R9.htm 0000009 - Disclosure - Employee Benefit Plan, Related-Party and Party-in-Interest Transactions Sheet http://www.commercebank.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactions Employee Benefit Plan, Related-Party and Party-in-Interest Transactions Notes 9 false false R10.htm 0000010 - Disclosure - Employee Benefit Plan, Fair Value and NAV Sheet http://www.commercebank.com/role/EmployeeBenefitPlanFairValueandNAV Employee Benefit Plan, Fair Value and NAV Notes 10 false false R11.htm 0000011 - Disclosure - Plan Termination Text Block Sheet http://www.commercebank.com/role/PlanTerminationTextBlock Plan Termination Text Block Notes 11 false false R12.htm 0000012 - Disclosure - Plan Amendment Text Block Sheet http://www.commercebank.com/role/PlanAmendmentTextBlock Plan Amendment Text Block Notes 12 false false R13.htm 0000013 - Disclosure - New Accounting Pronouncements, Text Block Sheet http://www.commercebank.com/role/NewAccountingPronouncementsTextBlock New Accounting Pronouncements, Text Block Notes 13 false false R14.htm 0000014 - Disclosure - Employee Benefit Plan, Subsequent Event Sheet http://www.commercebank.com/role/EmployeeBenefitPlanSubsequentEvent Employee Benefit Plan, Subsequent Event Notes 14 false false R15.htm 0000015 - Disclosure - Employee Benefit Plan, Schedule, Asset Held for Investment Sheet http://www.commercebank.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestment Employee Benefit Plan, Schedule, Asset Held for Investment Notes 15 false false R16.htm 0000016 - Disclosure - Employee Benefit Plan, Summary of Accounting Policy (Policies) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanSummaryofAccountingPolicyPolicies Employee Benefit Plan, Summary of Accounting Policy (Policies) Policies http://www.commercebank.com/role/EmployeeBenefitPlanSummaryofAccountingPolicy 16 false false R17.htm 0000017 - Disclosure - Employee Benefit Plan, Description of Plan (Tables) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanDescriptionofPlanTables Employee Benefit Plan, Description of Plan (Tables) Tables http://www.commercebank.com/role/EmployeeBenefitPlanDescriptionofPlan 17 false false R18.htm 0000020 - Disclosure - Company Stock Fund (Tables) Sheet http://www.commercebank.com/role/CompanyStockFundTables Company Stock Fund (Tables) Tables http://www.commercebank.com/role/CompanyStockFund 18 false false R19.htm 0000022 - Disclosure - Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Tables) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactionsTables Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Tables) Tables http://www.commercebank.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactions 19 false false R20.htm 0000023 - Disclosure - Employee Benefit Plan, Fair Value and NAV (Tables) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanFairValueandNAVTables Employee Benefit Plan, Fair Value and NAV (Tables) Tables http://www.commercebank.com/role/EmployeeBenefitPlanFairValueandNAV 20 false false R21.htm 0000028 - Disclosure - Employee Benefit Plan, Schedule, Asset Held for Investment (Tables) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestmentTables Employee Benefit Plan, Schedule, Asset Held for Investment (Tables) Tables http://www.commercebank.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestment 21 false false R22.htm 0000029 - Disclosure - Description of Plan (Narrative) (Details) Sheet http://www.commercebank.com/role/DescriptionofPlanNarrativeDetails Description of Plan (Narrative) (Details) Details 22 false false R23.htm 0000031 - Disclosure - Vesting Years of Service (Details) Sheet http://www.commercebank.com/role/VestingYearsofServiceDetails Vesting Years of Service (Details) Details 23 false false R24.htm 0000034 - Disclosure - Company Stock Fund (Narrative) (Details) Sheet http://www.commercebank.com/role/CompanyStockFundNarrativeDetails Company Stock Fund (Narrative) (Details) Details http://www.commercebank.com/role/CompanyStockFundTables 24 false false R25.htm 0000035 - Disclosure - Changes in ESOP Assets (Details) Sheet http://www.commercebank.com/role/ChangesinESOPAssetsDetails Changes in ESOP Assets (Details) Details 25 false false R26.htm 0000036 - Disclosure - Dividends Paid on Company Stock (Details) Sheet http://www.commercebank.com/role/DividendsPaidonCompanyStockDetails Dividends Paid on Company Stock (Details) Details 26 false false R27.htm 0000037 - Disclosure - Employee Benefit Plan, Tax Status (Narrative) (Details) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanTaxStatusNarrativeDetails Employee Benefit Plan, Tax Status (Narrative) (Details) Details http://www.commercebank.com/role/EmployeeBenefitPlanTaxStatus 27 false false R28.htm 0000038 - Disclosure - Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Details) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactionsDetails Employee Benefit Plan, Related-Party and Party-in-Interest Transactions (Details) Details http://www.commercebank.com/role/EmployeeBenefitPlanRelatedPartyandPartyinInterestTransactionsTables 28 false false R29.htm 0000039 - Disclosure - Fair Value Measurements (Narrative) (Details) Sheet http://www.commercebank.com/role/FairValueMeasurementsNarrativeDetails Fair Value Measurements (Narrative) (Details) Details 29 false false R30.htm 0000040 - Disclosure - Fair Value Measurements, Fair Value and NAV Hierarchy (Details) Sheet http://www.commercebank.com/role/FairValueMeasurementsFairValueandNAVHierarchyDetails Fair Value Measurements, Fair Value and NAV Hierarchy (Details) Details 30 false false R31.htm 0000041 - Disclosure - Fair Value Measurements, NAV Measurement Information (Details) Sheet http://www.commercebank.com/role/FairValueMeasurementsNAVMeasurementInformationDetails Fair Value Measurements, NAV Measurement Information (Details) Details 31 false false R32.htm 0000042 - Disclosure - Plan Termination Text Block (Narrative) (Details) Sheet http://www.commercebank.com/role/PlanTerminationTextBlockNarrativeDetails Plan Termination Text Block (Narrative) (Details) Details http://www.commercebank.com/role/PlanTerminationTextBlock 32 false false R33.htm 0000046 - Disclosure - Employee Benefit Plan, Schedule, Asset Held for Investment (Details) Sheet http://www.commercebank.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestmentDetails Employee Benefit Plan, Schedule, Asset Held for Investment (Details) Details http://www.commercebank.com/role/EmployeeBenefitPlanScheduleAssetHeldforInvestmentTables 33 false false All Reports Book All Reports cbsh-20251231.htm cbsh-20251231.xsd cbsh-20251231_def.xml cbsh-20251231_lab.xml cbsh-20251231_pre.xml http://fasb.org/us-gaap-ebp/2025 http://xbrl.sec.gov/dei/2025 true false