Investments Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Marketable Securities
Estimated Fair Value, Less than 12 Months	$ 153,230	$ 154,847
Estimated Fair Value, 12 Months or More	20,275	60,844
Estimated Fair Value, Total	173,505	215,691
Unrealized Losses, Less than 12 Months	6,742	1,742
Unrealized Losses, 12 Months or More	1,541	2,259
Unrealized Losses, Total	8,283	4,001
Fixed maturity securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	132,933	145,998
Estimated Fair Value, 12 Months or More	17,698	46,701
Estimated Fair Value, Total	150,631	192,699
Unrealized Losses, Less than 12 Months	3,747	1,351
Unrealized Losses, 12 Months or More	669	1,287
Unrealized Losses, Total	4,416	2,638
Obligations of states and political subdivisions
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	13,635
Estimated Fair Value, Total	13,635
Unrealized Losses, Less than 12 Months	363
Unrealized Losses, Total	363
Residential mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	5,220	61,933
Estimated Fair Value, 12 Months or More	38	31,655
Estimated Fair Value, Total	5,258	93,588
Unrealized Losses, Less than 12 Months	8	409
Unrealized Losses, 12 Months or More		500
Unrealized Losses, Total	8	909
Commercial mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months		36,398
Estimated Fair Value, 12 Months or More		866
Estimated Fair Value, Total		37,264
Unrealized Losses, Less than 12 Months		397
Unrealized Losses, Total		397
Other asset-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	2,464	21,281
Estimated Fair Value, 12 Months or More	8,924	462
Estimated Fair Value, Total	11,388	21,743
Unrealized Losses, Less than 12 Months	273	64
Unrealized Losses, 12 Months or More	159
Unrealized Losses, Total	432	64
Corporate and other securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	111,614	26,386
Estimated Fair Value, 12 Months or More	8,736	13,718
Estimated Fair Value, Total	120,350	40,104
Unrealized Losses, Less than 12 Months	3,103	481
Unrealized Losses, 12 Months or More	510	787
Unrealized Losses, Total	3,613	1,268
Equity securities
Equity Securities
Estimated Fair Value, Less than 12 Months	20,297	8,849
Estimated Fair Value, 12 Months or More	2,577	14,143
Estimated Fair Value, Total	22,874	22,992
Unrealized Losses, Less than 12 Months	2,995	391
Unrealized Losses, 12 Months or More	872	972
Unrealized Losses, Total	$ 3,867	$ 1,363