Schedule I - Summary of Investments - Other than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Summary of investments - other than investments in related parties
Cost or Amortized Cost	$ 1,403,920
Estimated Fair Value	1,507,587
Amount at which shown in the Balance Sheet	1,507,587
Total fixed maturities
Summary of investments - other than investments in related parties
Cost or Amortized Cost	1,189,951
Estimated Fair Value	1,256,653
Amount at which shown in the Balance Sheet	1,256,653
U.S. government and government agencies and authorities
Summary of investments - other than investments in related parties
Cost or Amortized Cost	231,731
Estimated Fair Value	243,462
Amount at which shown in the Balance Sheet	243,462
Obligations of states and political subdivisions
Summary of investments - other than investments in related parties
Cost or Amortized Cost	214,647
Estimated Fair Value	222,389
Amount at which shown in the Balance Sheet	222,389
Corporate and other securities
Summary of investments - other than investments in related parties
Cost or Amortized Cost	743,573
Estimated Fair Value	790,802
Amount at which shown in the Balance Sheet	790,802
Total equity securities
Summary of investments - other than investments in related parties
Cost or Amortized Cost	168,289
Estimated Fair Value	205,254
Amount at which shown in the Balance Sheet	205,254
Industrial, miscellaneous and all other
Summary of investments - other than investments in related parties
Cost or Amortized Cost	168,289
Estimated Fair Value	205,254
Amount at which shown in the Balance Sheet	205,254
Corporate and other securities
Summary of investments - other than investments in related parties
Cost or Amortized Cost	441
Estimated Fair Value	441
Amount at which shown in the Balance Sheet	441
Other invested assets
Summary of investments - other than investments in related parties
Cost or Amortized Cost	45,239
Estimated Fair Value	45,239
Amount at which shown in the Balance Sheet	45,239
Short term Investments
Summary of investments - other than investments in related parties
Cost or Amortized Cost	441
Estimated Fair Value	441
Amount at which shown in the Balance Sheet	$ 441