cm:Concept: us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionOther
| Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Other |
| us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionOther |
| Describe any other significant restriction on the ability to redeem or sell investments, comprising or included in the major category, of those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments) from which redemption is restricted as of the entity's measurement date. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionOther |