| Name | PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain |
|---|---|
| Namespace | http://fasb.org/srt/2020-01-31 |
| Prefix | srt |
| Data type | nonnum:domainItemType |
| Period type | duration |
| Substitution Group | xbrli:item |
| Balance | None |
| Nillable | True |
| Abstract | True |
| Name | Value | Role |
|---|---|---|
| TaxonomyVersion | 2018 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2017-08 | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedReferences | true | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedLabels | true | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedDocumentation | true | http://fasb.org/srt/role/changeNote/changeNote |
| PreviousDocumentation | State the name of the business segment being reported. Indicate whether the business segment is a consolidated property-casualty entity, an unconsolidated property-casualty subsidiary or has a proportionate share of the registrant and its subsidiaries' fifty percent-or-less owned property-casualty equity investee. | http://fasb.org/srt/role/changeNote/changeNote |