Investments - Gains and proceeds (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Investments
Net realized losses from sale of investments	$ 2	$ 1,078
Proceeds from sale of available-for-sale debt securities	1,100	32,000
Maximum
Investments
Net realized losses from sale of investments	100
Purchases of investments - debt securities	$ 100	$ 100

Amount of realized gain (loss) 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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount of cash outflow to acquire 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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-Publisher FASB
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Amount of cash inflow from sale 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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