cm:Level3TextBlock: us-gaap:DetailsOfImpairmentOfLongLivedAssetsHeldAndUsedByAssetTextBlock
| Details of Impairment of Long-Lived Assets Held and Used by Asset [Table Text Block] |
| us-gaap:DetailsOfImpairmentOfLongLivedAssetsHeldAndUsedByAssetTextBlock |
| Tabular disclosure for impairment of long-lived assets held and used by an entity which includes a description of the impaired long-lived asset and facts and circumstances leading to the impairment, aggregate amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired long-lived asset is reported. |
| cm:Level3TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DetailsOfImpairmentOfLongLivedAssetsHeldAndUsedByAssetTextBlock |
| ImpairedLongLivedAssetsHeldAndUsed |