| Standard label: | Gains (Losses) on Sales of Investment Real Estate | 
| Name: | us-gaap:GainsLossesOnSalesOfInvestmentRealEstate | 
| Documentation: | The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes. | 
| Object type: | cm:Concept | 
| Data type: | Monetary (xbrli:monetaryItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | Credit | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:GainsLossesOnSalesOfInvestmentRealEstate | 
| Label | Role | Language | 
| Gains (Losses) on Sales of Investment Real Estate | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(b)(7)(c)) | http://www.xbrl.org/2009/role/commonPracticeRef | 220 | 
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03(b)(9)(a)) | http://www.xbrl.org/2009/role/commonPracticeRef | 220 | 
| FASB Accounting Standards Codification 230 10 45 28 (b) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 | 
| FASB Accounting Standards Codification 942 220 S99 1 (SX 210.9-04(14)(d)) | http://www.xbrl.org/2009/role/commonPracticeRef | 942 | 
| FASB Accounting Standards Codification 944 220 S99 1 (SX 210.7-04(3)(a)) | http://www.xbrl.org/2009/role/commonPracticeRef | 944 | 
| FASB Accounting Standards Codification 944 360 50 1 | http://www.xbrl.org/2003/role/disclosureRef | 944 | 
| FASB Accounting Standards Codification 944 360 45 3 | http://www.xbrl.org/2003/role/disclosureRef | 944 | 
| FASB Accounting Standards Codification 944 360 45 4 | http://www.xbrl.org/2003/role/disclosureRef | 944 | 
| Part Of Roll Up: | 
| us-gaap:RealizedInvestmentGainsLosses |