cm:Concept: us-gaap:ObligationWithJointAndSeveralLiabilityArrangementDescription
| Obligation with Joint and Several Liability Arrangement, Description |
| us-gaap:ObligationWithJointAndSeveralLiabilityArrangementDescription |
| Description of the nature of the arrangement, including, but not limited to, how the liability arose, the relationships with other co-obligors, and the terms and conditions of the arrangement. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ObligationWithJointAndSeveralLiabilityArrangementDescription |