| Standard label: | Treasury Stock [Text Block] |
| Name: | us-gaap:TreasuryStockTextBlock |
| Documentation: | The entire disclosure for treasury stock, including, but not limited to, average cost per share, description of share repurchase program, shares repurchased, shares held for each class of treasury stock. |
| Object type: | cm:Level1TextBlock |
| 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:TreasuryStockTextBlock |
| Examples of this text block disclosure: | TreasuryStock |
| Label | Role | Language |
| Treasury Stock [Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 505 30 | http://fasb.org/us-gaap/role/ref/legacyRef | 505 |