Investments, Contractual Maturities of Available-for-sale Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Amortized Cost [Abstract]
Due in one year or less, Amortized Cost	$ 9,940
Due after one year through five years, Amortized Cost	115,480
Due after five years through ten years, Amortized Cost	79,235
Due after ten years, Amortized Cost	142,054
Total fixed maturities, Amortized Cost	714,817	$ 514,237
Estimated Fair Value [Abstract]
Due in one year or less, Estimated Fair Value	9,990
Due after one year through five years, Estimated Fair Value	118,611
Due after five years through ten years, Estimated Fair Value	82,314
Due after ten years, Estimated Fair Value	146,858
Estimated Fair Value	729,532	510,251
Asset-backed Securities [Member]
Amortized Cost [Abstract]
Without single maturity date, Amortized Cost	195,750
Total fixed maturities, Amortized Cost	195,750	151,137
Estimated Fair Value [Abstract]
Without single maturity date, Estimated Fair Value	197,970
Estimated Fair Value	197,970	149,867
Residential Mortgage-backed Securities [Member]
Amortized Cost [Abstract]
Without single maturity date, Amortized Cost	172,358
Total fixed maturities, Amortized Cost	172,358	110,717
Estimated Fair Value [Abstract]
Without single maturity date, Estimated Fair Value	173,789
Estimated Fair Value	$ 173,789	$ 108,421