cm:Concept: us-gaap:UndistributedEarningsLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted
| Undistributed Earnings (Loss) from Discontinued Operations Available to Common Shareholders, Diluted |
| us-gaap:UndistributedEarningsLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted |
| Amount of undistributed earnings (loss) from discontinued operations, allocated to common stock, as if earnings and addition from assumption of issuance of common shares for dilutive potential common shares, had been distributed. Excludes distributed earnings. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:UndistributedEarningsLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted |