cm:Concept: us-gaap:VariableInterestEntityActivityBetweenVIEAndEntityOtherMeasureOfActivityAmount
| Variable Interest Entity, Measure of Activity, Other, Amount |
| us-gaap:VariableInterestEntityActivityBetweenVIEAndEntityOtherMeasureOfActivityAmount |
| The amount of activity, consisting of a transaction or a measure not described elsewhere in the taxonomy, occurring during the period between the reporting entity and the Variable Interest Entity (VIE) or potential VIE. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:VariableInterestEntityActivityBetweenVIEAndEntityOtherMeasureOfActivityAmount |