| Standard label: | Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] | 
| Name: | us-gaap:LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock | 
| Documentation: | Tabular disclosure of maturity of undiscounted cash flows to be received by lessor on annual basis for operating lease. | 
| 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:LessorOperatingLeasePaymentsToBeReceivedMaturityTableTextBlock | 
| Label | Role | Language | 
| Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 842 30 50 12 | http://www.xbrl.org/2009/role/commonPracticeRef | 842 |