| Standard label: | Schedules of Concentration of Risk, by Risk Factor [Table Text Block] |
| Name: | us-gaap:SchedulesOfConcentrationOfRiskByRiskFactorTextBlock |
| Documentation: | Tabular disclosure of the nature of a concentration, a benchmark to which it is compared, and the percentage that the risk is to the benchmark. |
| 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:SchedulesOfConcentrationOfRiskByRiskFactorTextBlock |
| Examples of this text block disclosure: | ConcentrationOfRiskByRiskFactor |
| Label | Role | Language |
| Schedules of Concentration of Risk, by Risk Factor [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 275 10 50 16 | http://fasb.org/us-gaap/role/ref/legacyRef | 275 |
| FASB Accounting Standards Codification 275 10 50 18 | http://fasb.org/us-gaap/role/ref/legacyRef | 275 |
| FASB Accounting Standards Codification 275 10 50 20 | http://fasb.org/us-gaap/role/ref/legacyRef | 275 |
| FASB Accounting Standards Codification 275 10 50 21 | http://fasb.org/us-gaap/role/ref/legacyRef | 275 |
| FASB Accounting Standards Codification 825 10 50 20 | http://fasb.org/us-gaap/role/ref/legacyRef | 825 |
| FASB Accounting Standards Codification 825 10 50 21 | http://fasb.org/us-gaap/role/ref/legacyRef | 825 |