cm:Concept: us-gaap:SecurityOwnedAndSoldNotYetPurchasedFairValueSecuritySoldNotYetPurchased
| Security Owned and Sold, Not yet Purchased Fair Value, Security Sold, Not yet Purchased |
| us-gaap:SecurityOwnedAndSoldNotYetPurchasedFairValueSecuritySoldNotYetPurchased |
| Fair value of financial instruments sold short by a broker-dealer for their own account (proprietary securities) for trading or investment purposes determined by management based upon quoted prices of a financial instrument with similar characteristics or on a valuation technique or model. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:SecurityOwnedAndSoldNotYetPurchasedFairValueSecuritySoldNotYetPurchased |