cm:Concept: us-gaap:NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted
| Net Income (Loss) from Discontinued Operations Available to Common Shareholders, Diluted |
| us-gaap:NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted |
| Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) from discontinued operations available to common shareholders. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted |