cm:Concept: us-gaap:OwnshareLendingArrangementDescription
| Own-share Lending Arrangement, Description |
| us-gaap:OwnshareLendingArrangementDescription |
| A description of any outstanding share-lending arrangement on the entity's own stock including all significant terms such as the number of shares lent, the term of the arrangement, the circumstances under which cash settlement would be required, and any requirements for the counterparty (share borrower) to provide collateral. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:OwnshareLendingArrangementDescription |