cm:Level2TextBlock: us-gaap:GoodwillAndIntangibleAssetsPolicyTextBlock
| Goodwill and Intangible Assets, Policy [Policy Text Block] |
| us-gaap:GoodwillAndIntangibleAssetsPolicyTextBlock |
| Disclosure of accounting policy for goodwill and intangible assets. This accounting policy also may address how an entity assesses and measures impairment of goodwill and intangible assets. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:GoodwillAndIntangibleAssetsPolicyTextBlock |