cm:Concept: us-gaap:DiscontinuationOfInterestRateCashFlowHedge
| Discontinuation of Interest Rate Cash Flow Hedge |
| us-gaap:DiscontinuationOfInterestRateCashFlowHedge |
| Description of discontinued interest rate cash flow hedge relationships, including identification of hedged items and hedging instruments. Includes reasons for the discontinuation of the cash flow hedge and the effects of the discontinuation on the financial statements. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DiscontinuationOfInterestRateCashFlowHedge |