Investments - Available-for-sale Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less	$ 13,861
Due after one year through five years	26,881
Due after five years through ten years	15,191
Due after ten years	17,459
Securities with contractual maturities	73,392
Total debt securities	148,699	$ 149,954
Estimated Fair Value
Due in one year or less	13,944
Due after one year through five years	27,319
Due after five years through ten years	15,234
Due after ten years	17,674
Securities with contractual maturities	74,171
Total debt securities	149,188	151,999
Asset-backed securities
Amortized Cost
Total debt securities	31,691	20,987
Estimated Fair Value
Total debt securities	31,627	20,963
Mortgage-backed securities
Amortized Cost
Total debt securities	34,811	38,512
Estimated Fair Value
Total debt securities	34,457	38,854
Commercial mortgage-backed securities
Amortized Cost
Total debt securities	1,844	2,083
Estimated Fair Value
Total debt securities	1,906	2,126
Collateralized mortgage obligations
Amortized Cost
Total debt securities	6,961	6,361
Estimated Fair Value
Total debt securities	$ 7,027	$ 6,521