| Standard label: | Payments for (Proceeds from) Available-for-sale Securities, Short-term | 
| Name: | us-gaap:PaymentsForProceedsFromAvailableforsaleSecuritiesShortterm | 
| Documentation: | Amount of cash outflow (inflow) through acquisition (sale) of short-term available-for-sale securities. | 
| 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:PaymentsForProceedsFromAvailableforsaleSecuritiesShortterm | 
| Label | Role | Language | 
| Payments for (Proceeds from) Available-for-sale Securities, Short-term | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 230 10 45 9 (a) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 | 
| FASB Accounting Standards Codification 230 10 45 12 (a) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 | 
| FASB Accounting Standards Codification 230 10 45 13 (a) | http://www.xbrl.org/2009/role/commonPracticeRef | 230 |