Statutory Accounting and Regulation - Schedule of Affiliates' Surplus Regarding Policyholders (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
United Property & Casualty Insurance Company
Statutory Accounting Practices
Statutory capital and surplus required (percent of total liabilities)	10.00%
Statutory capital and surplus balance	$ 157,160	$ 155,587
Family Security Insurance Company
Statutory Accounting Practices
Statutory capital and surplus balance	20,473	16,269
Interboro Insurance Company
Statutory Accounting Practices
Statutory capital and surplus balance	43,939	$ 40,442
Minimum | United Property & Casualty Insurance Company
Statutory Accounting Practices
Statutory capital and surplus required	5,000
Minimum | Family Security Insurance Company
Statutory Accounting Practices
Statutory capital and surplus required	3,250
Minimum | Interboro Insurance Company
Statutory Accounting Practices
Statutory capital and surplus required	$ 4,700