| Standard label: | Credit Concentration Risk [Member] |
| Name: | us-gaap:CreditConcentrationRiskMember |
| Documentation: | Reflects the percentage that a specified receivable or amount at risk from a counterparty under a contractual arrangement is to a specified benchmark, such as total receivables, net revenues, pretax results. Risk is the materially adverse effects of loss attributable to (a) the failure to collect a significant receivable from a major customer or group of homogeneous accounts, or (b) a failure by a counterparty to perform under terms of a contractual arrangement. |
| Object type: | cm:Member |
| Data type: | [Member] (nonnum:domainItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:CreditConcentrationRiskMember |
| Label | Role | Language |
| Credit Concentration Risk [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 825 10 50 21 | http://fasb.org/us-gaap/role/ref/legacyRef | 825 |