Investments - Schedule of Available-for-Sale Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	$ 1,726,202
Fixed maturity securities, available-for-sale	1,662,278	$ 1,677,561
Fixed maturity securities
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	1,726,202	1,643,865
Total investments available-for-sale, Gross Unrealized Gains	8,831	46,253
Total investments available-for-sale, Gross Unrealized Losses	(72,755)	(12,557)
Fixed maturity securities, available-for-sale	1,662,278	1,677,561
State and municipal
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	337,908	323,773
Total investments available-for-sale, Gross Unrealized Gains	2,865	12,156
Total investments available-for-sale, Gross Unrealized Losses	(21,281)	(2,212)
Fixed maturity securities, available-for-sale	319,492	333,717
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	260,942	246,586
Total investments available-for-sale, Gross Unrealized Gains	462	2,384
Total investments available-for-sale, Gross Unrealized Losses	(13,503)	(2,339)
Fixed maturity securities, available-for-sale	247,901	246,631
Corporate
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	736,153	711,930
Total investments available-for-sale, Gross Unrealized Gains	5,059	26,119
Total investments available-for-sale, Gross Unrealized Losses	(25,837)	(5,714)
Fixed maturity securities, available-for-sale	715,375	732,335
Commercial mortgage and asset-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	315,566	301,247
Total investments available-for-sale, Gross Unrealized Gains	277	4,941
Total investments available-for-sale, Gross Unrealized Losses	(10,086)	(1,700)
Fixed maturity securities, available-for-sale	305,757	304,488
U.S. Treasury securities and obligations guaranteed by the U.S. government
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	75,633	60,329
Total investments available-for-sale, Gross Unrealized Gains	168	653
Total investments available-for-sale, Gross Unrealized Losses	(2,048)	(592)
Fixed maturity securities, available-for-sale	$ 73,753	$ 60,390