Investments, Debt Securities, Amortized Cost and Fair Value by Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Available-for-Sale Debt Securities, Amortized Cost [Abstract]
Due in one year or less	$ 22,771
Due after one year through five years	92,295
Due after five years through ten years	40,656
Due after ten years	88,120
Amortized cost	243,842	$ 242,242
Available-for-Sale Debt Securities, Fair Value [Abstract]
Due in one year or less	22,742
Due after one year through five years	94,069
Due after five years through ten years	41,115
Due after ten years	89,101
Fair value	$ 247,027	$ 241,010

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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