cm:Member: us-gaap:FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain
| Fair Value by Liability Class [Domain] |
| us-gaap:FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain |
| Represents classes of liabilities measured and disclosed at fair value. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain |