cm:Concept: us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionDescription
| Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction, Description |
| us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionDescription |
| Describes the circumstances in which an otherwise redeemable investment, 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) is not redeemable (for example, investments subject to a lockup or gate). |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRestrictionDescription |