Investments Contractual Maturities of Available-for-Sale Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less, Amortized Cost	$ 3,914
Due after one year through five years, Amortized Cost	95,702
Due after five years through ten years, Amortized Cost	50,116
Due after ten years, Amortized Cost	101,870
Total fixed maturities, Amortized Cost	577,183	$ 514,237
Estimated Fair Value
Due in one year or less, Estimated Fair Value	3,922
Due after one year through five years, Estimated Fair Value	98,079
Due after five years through ten years, Estimated Fair Value	52,709
Due after ten years, Estimated Fair Value	106,580
Estimated Fair Value	590,077	510,251
Commercial mortgage and asset-backed securities [Member]
Amortized Cost
Without single maturity date, Amortized Cost	175,355
Total fixed maturities, Amortized Cost	175,355	151,137
Estimated Fair Value
Without single maturity date, Estimated Fair Value	177,865
Estimated Fair Value	177,865	149,867
Residential mortgage-backed securities [Member]
Amortized Cost
Without single maturity date, Amortized Cost	150,226
Total fixed maturities, Amortized Cost	150,226	110,717
Estimated Fair Value
Without single maturity date, Estimated Fair Value	150,922
Estimated Fair Value	$ 150,922	$ 108,421