cm:Concept: us-gaap:LongLivedAssetsHeldForSaleDescription
| Long Lived Assets Held-for-sale, Description |
| us-gaap:LongLivedAssetsHeldForSaleDescription |
| A description of the assets to be disposed of and the facts and circumstances leading to the expected disposal, and the expected manner and timing of the disposal (generally no more than 12 months from the date of the balance sheet). |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LongLivedAssetsHeldForSaleDescription |