Investments - Available-for-sale Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less	$ 9,583
Due after one year through five years	31,619
Due after five years through ten years	14,762
Due after ten years	9,352
Securities with contractual maturities	65,316
Total debt securities	124,046	$ 122,678
Estimated Fair Value
Due in one year or less	9,588
Due after one year through five years	32,158
Due after five years through ten years	15,314
Due after ten years	9,741
Securities with contractual maturities	66,801
Total debt securities	125,704	120,440
Asset-backed securities
Amortized Cost
Total debt securities	20,167	24,468
Estimated Fair Value
Total debt securities	20,194	24,284
Mortgage-backed securities
Amortized Cost
Total debt securities	30,206	30,377
Estimated Fair Value
Total debt securities	30,132	29,240
Commercial mortgage-backed securities
Amortized Cost
Total debt securities	4,271	4,025
Estimated Fair Value
Total debt securities	4,464	3,953
Collateralized mortgage obligations
Amortized Cost
Total debt securities	4,086	2,178
Estimated Fair Value
Total debt securities	$ 4,113	$ 2,144