cm:Member: us-gaap:DefinedBenefitPlanEquitySecuritiesCommonStockEmployerRelatedPartyMember
| Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party [Member] |
| us-gaap:DefinedBenefitPlanEquitySecuritiesCommonStockEmployerRelatedPartyMember |
| Security representing ownership in corporation or other legal entity, for which ownership is represented by share of common stock of employer; in which defined benefit plan asset is invested. Includes, but is not limited to, common stock issued or managed by related party of employer. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:DefinedBenefitPlanEquitySecuritiesCommonStockEmployerRelatedPartyMember |