| Standard label: | Share-based Payment Arrangement, Activity [Table Text Block] |
| Name: | us-gaap:ScheduleOfShareBasedCompensationActivityTableTextBlock |
| Documentation: | Tabular disclosure of activity for award under share-based payment arrangement. Includes, but is not limited to, outstanding award at beginning and end of year, granted, exercised, forfeited, and weighted-average grant date fair value. |
| Object type: | cm:Level3TextBlock |
| 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:ScheduleOfShareBasedCompensationActivityTableTextBlock |
| Examples of this text block disclosure: | SharebasedCompensationActivity |
| Label | Role | Language |
| Share-based Payment Arrangement, Activity [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 718 10 50 2 (c)(2) | http://fasb.org/us-gaap/role/ref/legacyRef | 718 |
| FASB Accounting Standards Codification 718 10 50 2 (d) | http://fasb.org/us-gaap/role/ref/legacyRef | 718 |
| FASB Accounting Standards Codification 718 10 50 2 (e) | http://fasb.org/us-gaap/role/ref/legacyRef | 718 |