cm:Concept: us-gaap:DeferredCompensationArrangementWithIndividualSharesAuthorizedForIssuance
| Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance |
| us-gaap:DeferredCompensationArrangementWithIndividualSharesAuthorizedForIssuance |
| The maximum number of shares authorized for issuance under the deferred compensation arrangement as of the balance sheet date. |
| cm:Concept |
| Shares (xbrli:sharesItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:DeferredCompensationArrangementWithIndividualSharesAuthorizedForIssuance |