Investments, Debt Securities, Amortized Cost and Fair Value by Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Available-for-Sale Debt Securities, Amortized Cost [Abstract]
Due in one year or less	$ 23,487
Due after one year through five years	77,822
Due after five years through ten years	110,884
Due after ten years	151,843
Amortized cost	364,036	$ 287,521
Available-for-Sale Debt Securities, Fair Value [Abstract]
Due in one year or less	23,744
Due after one year through five years	79,805
Due after five years through ten years	111,619
Due after ten years	153,834
Fair value	$ 369,002	$ 295,189