cm:Member: us-gaap:TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember
| Trust Preferred Securities Subject to Mandatory Redemption [Member] |
| us-gaap:TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember |
| Preferred securities 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, that are issued by a consolidated trust to outside investors where the trust uses the proceeds of the issuance of those securities to purchase, from the financial institution that established the trust, an equivalent amount of junior subordinated debentures or other loans having stated maturities. |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember |