Note 4 - Derivative and Other Hedging Instruments - Schedule of Derivative Positions (Details) - Short [Member] - USD ($) $ in Thousands		Dec. 31, 2022	Dec. 31, 2021
Five Year Treasury Note Futures [Member]
Average contract notional amount		$ 750,500	$ 369,000
Weighted average entry rate		4.20%	1.56%
Average receive rate		4.22%	1.62%
Open Equity		$ (100)	$ 1,013
Ten Year Ultra Future [Member]
Average contract notional amount		$ 174,500	$ 220,000
Weighted average entry rate	[1]	3.66%	1.22%
Average receive rate		3.79%	1.09%
Open Equity	[2]	$ 965	$ (3,861)

[1] 5-Year T-Note futures contracts were valued at a price of $120.98 at December 31, 2022 and $126.16 at December 31, 2021. The contract values of the short positions were $446.4 million and $87.1 million at December 31, 2022 and December 31, 2021, respectively. 10-Year Ultra futures contracts were valued at price of $146.44 at December 31, 2022. The contract value of the short position was $322.2 million at December 31, 2022.

[2] Open equity represents the cumulative gains (losses) recorded on open futures positions from inception.