General - Investments - Amortized Cost (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Amortized cost
Amortized Cost	$ 155,579	$ 143,561
Gross Unrealized Gains	3	14
Gross Unrealized Losses	(64)	(116)
Estimated Fair Value	155,518	143,459
U.S. Government and agency securities
Amortized cost
Amortized Cost	16,529	42,389
Gross Unrealized Gains	1	11
Gross Unrealized Losses		(1)
Estimated Fair Value	16,530	42,399
Corporate debt securities
Amortized cost
Amortized Cost	125,452	99,861
Gross Unrealized Gains		3
Gross Unrealized Losses	(63)	(115)
Estimated Fair Value	125,389	99,749
Taxable municipal bonds
Amortized cost
Amortized Cost	12,298
Gross Unrealized Gains	2
Gross Unrealized Losses	(1)
Estimated Fair Value	12,299
Certificates of deposit
Amortized cost
Amortized Cost	1,300	1,311
Estimated Fair Value	$ 1,300	$ 1,311

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on 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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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount 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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