Note 9 - Fair Value Disclosures - Level 3 Rollforward (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Beginning of Period		$ 2,522	$ 2,756
Net trading		(57)
Gains & losses (1)	[1]	(604)	(123)
Accretion of income (1)	[1]	124	414
Purchases		638
Sales and returns of capital		(5,601)	(525)
Reclassification of RTLs		5,278
Transfer out of Level 3 (2)	[2]	(2,300)
End of Period			2,522
Change in unrealized gains / (losses) (3)	[3]		$ (4)

[1] Gains and losses on and accretion of income on other investments, at fair value are recorded as a component of principal transactions and other income in the consolidated statements of operations.

[2] RTL was reclassified from level 3 to level 2 due to availability of observable inputs.

[3] Represents the change in unrealized gains and losses for the period included in earnings for assets held at the end of the reporting period.