| Standard label: | Revenue Recognition, Retail Land Sales [Policy Text Block] |
| Name: | us-gaap:RevenueRecognitionRetailLandSales |
| Documentation: | Disclosure of accounting policy for the timing and amount of revenue recognized on retail sales of real estate. The entity also may disclose its treatment of any unearned or deferred revenue that arises from the transaction. |
| Object type: | cm:Level2TextBlock |
| Data type: | Text Block (HTML) (nonnum:textBlockItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:RevenueRecognitionRetailLandSales |
| Label | Role | Language |
| Revenue Recognition, Retail Land Sales [Policy Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 235 10 50 3 | http://fasb.org/us-gaap/role/ref/otherTransitionRef | 235 |