IndexSupplemental Employee Retirement Plan [Member]
| Name | SupplementalEmployeeRetirementPlanDefinedBenefitMember |
|---|---|
| Namespace | http://fasb.org/us-gaap/2020-01-31 |
| Prefix | us-gaap |
| Data type | nonnum:domainItemType |
| Period type | duration |
| Substitution Group | xbrli:item |
| Balance | None |
| Nillable | True |
| Abstract | True |
Labels
| Text | Lang | Role | Container role |
|---|---|---|---|
| Supplemental Employee Retirement Plan [Member] | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Plan designed to provide limited group of employees with supplemental retirement benefits, in addition to other pension benefits. Includes, but is not limited to, defined benefit and defined contribution plans. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
Related Parent Concepts
| Name | Relation Type | Role | |
|---|---|---|---|
 | us-gaap:RetirementPlanTypeDomain | domain-member | http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists |