cm:Member: us-gaap:SharesSubjectToMandatoryRedemptionFinancialInstrumentDomain
| Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] |
| us-gaap:SharesSubjectToMandatoryRedemptionFinancialInstrumentDomain |
| Identifying description of each financial instrument that embodies an unconditional obligation requiring the issuer to redeem the securities by transferring the assets at a specified or determinable date (or dates) or upon an event that is certain to occur. Examples are preferred stock or trust preferred securities, each of which has redemption rights beyond the control of the issuer on a specified date or upon an event that is certain to occur. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:SharesSubjectToMandatoryRedemptionFinancialInstrumentDomain |