cm:Concept: us-gaap:DirectFinancingLeaseRiskStrategyResidualAsset
| Direct Financing Lease, Risk Strategy, Residual Asset |
| us-gaap:DirectFinancingLeaseRiskStrategyResidualAsset |
| Description of risk management strategy for residual asset under direct financing lease. Includes, but is not limited to, buyback agreement and variable lease payments for use in excess of specified limits. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DirectFinancingLeaseRiskStrategyResidualAsset |