| Standard label: | Available-for-sale Securities, Restricted | 
| Name: | us-gaap:AvailableForSaleSecuritiesRestricted | 
| Documentation: | The carrying amount of securities categorized neither as held-to-maturity nor trading which serve as security for borrowings or other arrangements. | 
| Object type: | cm:Concept | 
| Data type: | Monetary (xbrli:monetaryItemType) | 
| Period type: | As Of (instant) | 
| Balance type: | Debit | 
| Abstract: | false | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AvailableForSaleSecuritiesRestricted | 
| Label | Role | Language | 
| Available-for-sale Securities, Restricted | http://www.xbrl.org/2003/role/label | en-US | 
| Available-for-sale Securities, Restricted, Total | http://www.xbrl.org/2003/role/totalLabel | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 235 10 S99 1 (SX210.4-08(b)) | http://fasb.org/us-gaap/role/ref/legacyRef | 235 | 
| FASB Accounting Standards Codification 310 10 50 5 | http://fasb.org/us-gaap/role/ref/legacyRef | 310 | 
| FASB Accounting Standards Codification 942 210 S99 1 (SX 210.9-03(6)) | http://fasb.org/us-gaap/role/ref/legacyRef | 942 | 
| FASB Accounting Standards Codification 944 210 S99 1 (SX 210.7-03(a)(1)) | http://fasb.org/us-gaap/role/ref/legacyRef | 944 | 
| FASB Accounting Standards Codification 946 10 S99 3 (SX 210.6-03(f)) | http://fasb.org/us-gaap/role/ref/legacyRef | 946 | 
| FASB Accounting Standards Codification 946 320 S99 1 (SX 210.12-12) | http://fasb.org/us-gaap/role/ref/legacyRef | 946 |