cm:Concept: us-gaap:SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleOtherInformation
| Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Other Information |
| us-gaap:SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleOtherInformation |
| Other information relative to a tax position which it is reasonably possible that the total amount of the unrecognized tax benefit will significantly increase or decrease within twelve months of the balance sheet date. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleOtherInformation |