General - Investments by Maturity Date (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Investments amortized cost maturity dates 2020	$ 321,201
Investments amortized cost maturity dates 2021	35,356
Amortized Cost	356,557	$ 344,965
Estimated Fair Value
Investments fair value maturity dates 2020	321,197
Investments fair value maturity dates 2020	35,284
Estimated Fair Value	$ 356,481	$ 345,157

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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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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