Note 5 - Marketable Securities - Change in Equity sold and Change in Unrealized Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Net gain/(losses) recognized on equity securities	$ 2,927	$ (4,369)
Less: net gains/(losses) recognized during the period on equity securities sold during the period	(81)	1,661
Unrealized gain/(losses) during the reporting period on equity securities held at the reporting date	$ 3,008	$ (6,030)

Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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