cm:Concept: us-gaap:InvestmentCompanyInvestmentsAppreciationDeprecationGreaterThanFivePercentOfNetAssets
| Investment Company, Investment Appreciation (Deprecation) Greater than Five Percent of Net Assets [true false] |
| us-gaap:InvestmentCompanyInvestmentsAppreciationDeprecationGreaterThanFivePercentOfNetAssets |
| Indicates (true false) whether appreciation (depreciation) on open futures contract of underlying constitutes more than five percent of net assets. |
| cm:Concept |
| Yes/No (xbrli:booleanItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:InvestmentCompanyInvestmentsAppreciationDeprecationGreaterThanFivePercentOfNetAssets |