cm:Concept: us-gaap:RestructuringCostsAndAssetImpairmentCharges
| Restructuring Costs and Asset Impairment Charges |
| us-gaap:RestructuringCostsAndAssetImpairmentCharges |
| Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:RestructuringCostsAndAssetImpairmentCharges |