| Standard label: | Accounting Standards Update 2017-08 [Member] |
| Name: | us-gaap:AccountingStandardsUpdate201708Member |
| Documentation: | Accounting Standards Update 2017-08 Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. |
| Object type: | cm:Member |
| Data type: | [Member] (nonnum:domainItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AccountingStandardsUpdate201708Member |
| Label | Role | Language |
| Accounting Standards Update 2017-08 [Member] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 310 20 65 1 | http://www.xbrl.org/2003/role/disclosureRef | 310 |