Investments, Debt Securities, Amortized Cost and Fair Value by Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Available-for-Sale Debt Securities, Amortized Cost [Abstract]
Due in one year or less	$ 10,484
Due after one year through five years	92,283
Due after five years through ten years	136,959
Due after ten years	153,439
Amortized cost	393,165	$ 287,521
Available-for-Sale Debt Securities, Fair Value [Abstract]
Due in one year or less	10,602
Due after one year through five years	93,835
Due after five years through ten years	137,577
Due after ten years	155,029
Fair value	$ 397,043	$ 295,189

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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