| Standard label: | Schedule of Line of Credit Facilities [Table Text Block] |
| Name: | us-gaap:ScheduleOfLineOfCreditFacilitiesTextBlock |
| Documentation: | Tabular disclosure of short-term or long-term contractual arrangements with lenders, including letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. |
| 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:ScheduleOfLineOfCreditFacilitiesTextBlock |
| Examples of this text block disclosure: | LineOfCreditFacility |
| Label | Role | Language |
| Schedule of Line of Credit Facilities [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02.19(b),22(b)) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 |
| FASB Accounting Standards Codification 235 10 S99 1 (SX 210.4-08.(e),(f)) | http://fasb.org/us-gaap/role/ref/legacyRef | 235 |