cm:Concept: us-gaap:GainsLossesOnSalesOfOtherRealEstate
| Gains (Losses) on Sales of Other Real Estate |
| us-gaap:GainsLossesOnSalesOfOtherRealEstate |
| The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, and write-downs of other real estate owned after acquisition or physical possession. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:GainsLossesOnSalesOfOtherRealEstate |