Investments, Fixed Maturities with Unrealized Losses (Details) $ in Thousands	Mar. 31, 2023 USD ($) Securities	Dec. 31, 2022 USD ($)
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Less than 12 months, fair value	$ 412,693	$ 794,302
Less than 12 months, unrealized losses	16,307	87,867
More than 12 months, fair value	650,942	238,021
More than 12 months, unrealized losses	$ 104,103	52,765
Fixed Maturities [Member]
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Number of fixed maturity securities classified as available for sale | Securities	877
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Less than 12 months, fair value	$ 80,775	90,245
Less than 12 months, unrealized losses	2,009	5,327
More than 12 months, fair value	77,265	47,238
More than 12 months, unrealized losses	12,305	10,364
Obligations of States and Political Subdivisions [Member]
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Less than 12 months, fair value	75,542	261,465
Less than 12 months, unrealized losses	4,515	49,327
More than 12 months, fair value	233,732	47,945
More than 12 months, unrealized losses	48,390	16,493
Corporate Securities [Member]
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Less than 12 months, fair value	198,944	298,706
Less than 12 months, unrealized losses	8,137	22,272
More than 12 months, fair value	177,785	72,959
More than 12 months, unrealized losses	24,427	13,449
Mortgage-Backed Securities [Member]
Debt Securities, Fair Value and Unrealized Losses by Fixed Maturities [Abstract]
Less than 12 months, fair value	57,432	143,886
Less than 12 months, unrealized losses	1,646	10,941
More than 12 months, fair value	162,160	69,879
More than 12 months, unrealized losses	$ 18,981	$ 12,459