cm:Concept: us-gaap:IndefiniteLivedIntangibleAssetsPeriodIncreaseDecrease
| Indefinite-lived Intangible Assets, Period Increase (Decrease) |
| us-gaap:IndefiniteLivedIntangibleAssetsPeriodIncreaseDecrease |
| Amount of increase (decrease) of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:IndefiniteLivedIntangibleAssetsPeriodIncreaseDecrease |