Investments - Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less, Amortized Cost	$ 31,705
Due after one year through five years, Amortized Cost	281,016
Due after five years though ten years, Amortized Cost	318,596
Due after ten years through twenty years, Amortized Cost	46,525
Due after twenty years, Amortized Cost	693
Asset-backed securities, Amortized Cost	472,832
Totals, Amortized Cost	1,151,367	$ 1,187,857
Estimated Fair Value
Due in one year or less, Fair Value	31,649
Due after one year through five years, Fair Value	266,832
Due after five years through ten years, Fair Value	288,221
Due after ten years through twenty years, Fair Value	43,241
Due after twenty years, Fair Value	653
Asset-backed securities, Fair Value	441,645
Totals, Fair Value	$ 1,072,241	$ 1,218,279