cm:Concept: us-gaap:PaymentsForProceedsFromDepositsOnRealEstateAcquisitions
| Payments for (Proceeds from) Deposits on Real Estate Acquisitions |
| us-gaap:PaymentsForProceedsFromDepositsOnRealEstateAcquisitions |
| Net cash outflow or inflow from the amount given in advance to show intention to complete the acquisition piece of land, anything permanently fixed to it, including buildings, structures on it, and so forth. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:PaymentsForProceedsFromDepositsOnRealEstateAcquisitions |