Note 2 - Ownership Interests and Advances (Details Textual) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended	24 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2023	Dec. 31, 2020
Equity Securities without Readily Determinable Fair Value, Amount	$ 11,564		$ 11,564		$ 19,951
Impairment of Other Method Securities	2,500		2,500
Preferred Equity in Acquiror in Connection with Sale of Zipnosis, Inc [Member]
Equity Securities without Readily Determinable Fair Value, Amount	$ 15,300		15,300
Zipnosis [Member]
Proceeds from Sale of Equity Method Investments			3,500
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 17,300
Investment Owned, Balance, Shares (in shares)		1.3
Bright Health [Member]
Investment Owned, Balance, Shares (in shares)	1.3		1.3
Trading Security, Unrealized Gain (Loss)	$ (11,900)	$ 7,400
Flashtalking [Member]
Proceeds From Sale of Other Method Investment			$ 44,800
Other Method Investment, Realized Gain (Loss)			32,300
Flashtalking [Member] | Forecast [Member]
Contingent Proceeds from Other Method Investment				$ 700
WebLinc, Inc. [Member]
Proceeds from Sale of Equity Method Investments			3,600
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 100
Disposal Group, Including Discontinued Operation, Period of Contingent Proceeds (Month)			15 months
T-Rex Group, Inc [Member]
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 900
Proceeds From Sale of Other Method Investment			3,000
Velano Vascular [Member]
Proceeds from Sale of Equity Method Investments			3,500
Equity Method Investment, Realized Gain (Loss) on Disposal, Total			$ 1,900
Disposal Group, Including Discontinued Operation, Period of Contingent Proceeds (Month)			12 months