Investments - Length Of Time, Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Marketable Securities
Estimated Fair Value, Less than 12 Months	$ 298,906	$ 301,386
Estimated Fair Value, 12 Months or More	467,118	634,845
Estimated Fair Value, Total	766,024	936,231
Unrealized Losses, Less than 12 Months	6,039	9,375
Unrealized Losses, 12 Months or More	37,748	68,080
Unrealized Losses, Total	43,787	77,455
Subtotal, fixed maturity securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	229,982	252,118
Estimated Fair Value, 12 Months or More	459,151	613,560
Estimated Fair Value, Total	689,133	865,678
Unrealized Losses, Less than 12 Months	877	5,345
Unrealized Losses, 12 Months or More	34,945	63,030
Unrealized Losses, Total	35,822	68,375
U.S. Treasury securities
Fixed Maturity Securities
Estimated Fair Value, 12 Months or More	1,474	1,742
Estimated Fair Value, Total	1,474	1,742
Unrealized Losses, 12 Months or More	28	77
Unrealized Losses, Total	28	77
Obligations of states and political subdivisions
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	1,199	13,289
Estimated Fair Value, 12 Months or More	10,684	19,209
Estimated Fair Value, Total	11,883	32,498
Unrealized Losses, Less than 12 Months	6	315
Unrealized Losses, 12 Months or More	1,645	2,270
Unrealized Losses, Total	1,651	2,585
Residential mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	26,318	94,528
Estimated Fair Value, 12 Months or More	156,857	162,260
Estimated Fair Value, Total	183,175	256,788
Unrealized Losses, Less than 12 Months	153	2,401
Unrealized Losses, 12 Months or More	15,229	24,134
Unrealized Losses, Total	15,382	26,535
Commercial mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	15,491	3,050
Estimated Fair Value, 12 Months or More	103,960	121,152
Estimated Fair Value, Total	119,451	124,202
Unrealized Losses, Less than 12 Months	108	9
Unrealized Losses, 12 Months or More	6,331	10,831
Unrealized Losses, Total	6,439	10,840
Other asset-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	95,322	11,298
Estimated Fair Value, 12 Months or More	10,113	22,018
Estimated Fair Value, Total	105,435	33,316
Unrealized Losses, Less than 12 Months	146	278
Unrealized Losses, 12 Months or More	1,050	1,616
Unrealized Losses, Total	1,196	1,894
Corporate and other securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	91,652	129,953
Estimated Fair Value, 12 Months or More	176,063	287,179
Estimated Fair Value, Total	267,715	417,132
Unrealized Losses, Less than 12 Months	464	2,342
Unrealized Losses, 12 Months or More	10,662	24,102
Unrealized Losses, Total	11,126	26,444
Equity securities
Equity Securities
Estimated Fair Value, Less than 12 Months	68,924	49,268
Estimated Fair Value, 12 Months or More	7,967	21,285
Estimated Fair Value, Total	76,891	70,553
Unrealized Losses, Less than 12 Months	5,162	4,030
Unrealized Losses, 12 Months or More	2,803	5,050
Unrealized Losses, Total	$ 7,965	$ 9,080