cm:Level2TextBlock: us-gaap:LandUnderOptionArrangementsPolicy
| Land under Option Arrangements, Policy [Policy Text Block] |
| us-gaap:LandUnderOptionArrangementsPolicy |
| Disclosure of accounting policy for including or excluding land under option arrangements in financial reports, which may include a discussion of options on land owned by variable interest entities, and timing and manner in which related impairment losses are determined and recognized. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
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| us-gaap:LandUnderOptionArrangementsPolicy |