cm:Concept: us-gaap:LesseeOperatingLeaseLeaseNotYetCommencedRestrictionOrCovenant
| Lessee, Operating Lease, Lease Not yet Commenced, Restriction or Covenant |
| us-gaap:LesseeOperatingLeaseLeaseNotYetCommencedRestrictionOrCovenant |
| Description of restriction or covenant imposed by operating lease that has not yet commenced. Includes, but is not limited to, those relating to dividends or incurring additional financial obligations. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LesseeOperatingLeaseLeaseNotYetCommencedRestrictionOrCovenant |