cm:Member: us-gaap:ParticipatingPreferredStockSubjectToMandatoryRedemptionMember
| Participating Preferred Stock Subject to Mandatory Redemption [Member] |
| us-gaap:ParticipatingPreferredStockSubjectToMandatoryRedemptionMember |
| Shares that embody 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. These shares 1) provide a specific dividend that is paid before dividends are paid to common stock holders, 2) take precedence over common stock in the event of a liquidation, 3) do not enjoy any of the voting rights of common stockholders, and 4) pay an additional dividend (the participating dividend) when common stock dividends exceed a specified amount. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:ParticipatingPreferredStockSubjectToMandatoryRedemptionMember |