Investments Contractual Maturities of Available-for-Sale Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less, Amortized Cost	$ 7,749
Due after one year through five years, Amortized Cost	258,045
Due after five years through ten years, Amortized Cost	244,902
Due after ten years, Amortized Cost	283,724
Total fixed maturities, Amortized Cost	1,521,792	$ 1,371,519
Estimated Fair Value
Due in one year or less, Estimated Fair Value	7,766
Due after one year through five years, Estimated Fair Value	251,927
Due after five years through ten years, Estimated Fair Value	233,059
Due after ten years, Estimated Fair Value	268,077
Estimated Fair Value	1,461,415	1,392,066
Asset-backed securities [Member]
Amortized Cost
Without single maturity date, Amortized Cost	275,052
Total fixed maturities, Amortized Cost	275,052	299,810
Estimated Fair Value
Without single maturity date, Estimated Fair Value	273,658
Estimated Fair Value	273,658	301,775
Residential mortgage-backed securities [Member]
Amortized Cost
Without single maturity date, Amortized Cost	381,691
Total fixed maturities, Amortized Cost	381,691	340,804
Estimated Fair Value
Without single maturity date, Estimated Fair Value	358,035
Estimated Fair Value	358,035	337,685
Commercial mortgage-backed securities
Amortized Cost
Without single maturity date, Amortized Cost	70,629
Total fixed maturities, Amortized Cost	70,629	57,000
Estimated Fair Value
Without single maturity date, Estimated Fair Value	68,893
Estimated Fair Value	$ 68,893	$ 59,227