cm:Concept: us-gaap:ConcentrationRiskServiceProvided
| Concentration Risk, Service Provided |
| us-gaap:ConcentrationRiskServiceProvided |
| Description of risks that arise due to the volume of revenue generated by a particular service or other reliance placed on the success of that service. At a minimum, the description informs financial statement users of the general nature of the risk. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ConcentrationRiskServiceProvided |