2. Short-Term Investments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Cost	$ 102,300	$ 37,032
Gross unrealized gain	537	45
Gross unrealized loss	(367)	(423)
Fair value	102,470	36,654
Trading securities - Debt [Member]
Cost	86,157	33,643
Gross unrealized gain	240	18
Gross unrealized loss	(7)	(19)
Fair value	86,390	33,642
Trading securities - Equity [Member]
Cost	16,143	3,389
Gross unrealized gain	297	27
Gross unrealized loss	(360)	(404)
Fair value	$ 16,080	$ 3,012

Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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