| Standard label: | Occupancy, Net | 
| Name: | us-gaap:OccupancyNet | 
| Documentation: | Amount of net occupancy expense that may include items, such as depreciation of facilities and equipment, lease expenses, property taxes and property and casualty insurance expense. | 
| Object type: | cm:Concept | 
| Data type: | Monetary (xbrli:monetaryItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | Debit | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OccupancyNet | 
| Label | Role | Language | 
| Occupancy, Net | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 220 10 S99 2 (SX 210.5-03.6) | http://fasb.org/us-gaap/role/ref/legacyRef | 220 | 
| FASB Accounting Standards Codification 840 30 50 1 | http://fasb.org/us-gaap/role/ref/legacyRef | 840 | 
| FASB Accounting Standards Codification 942 220 S99 1 (SX 210.9-04.14(b)) | http://fasb.org/us-gaap/role/ref/legacyRef | 942 | 
| Part Of Roll Up: | 
| us-gaap:CommunicationsInformationTechnologyAndOccupancy |