Note 5 - Derivative and Other Hedging Instruments - Schedule of Derivative Positions (Details) - Short [Member] - USD ($) $ in Thousands		Sep. 30, 2024	Dec. 31, 2023
Ten Year Ultra Futures [Member]
Average contract notional amount	[1]	$ 12,500	$ 320,000
Weighted average entry rate	[1]	3.73%	4.38%
Average receive rate	[1]	3.62%	4.39%
Open Equity	[1],[2]	$ (88)	$ (11,393)
Five Year Treasury Note Futures [Member]
Average contract notional amount	[1]		$ 421,500
Weighted average entry rate	[1]		4.36%
Average receive rate	[1]		4.04%
Open Equity	[1],[2]		$ (9,936)
Three Month SOFR Futures Ending in December 2024 [Member]
Average contract notional amount		$ 241,250	$ 25,000
Weighted average entry rate		4.78%	4.27%
Average receive rate		4.73%	4.10%
Open Equity	[2]	$ (110)	$ (44)
Three Month SOFR Futures Ending in March 2025 [Member]
Average contract notional amount		$ 129,250	$ 25,000
Weighted average entry rate		4.23%	3.90%
Average receive rate		4.04%	3.73%
Open Equity	[2]	$ (242)	$ (43)
Three Month SOFR Futures, Ending June 2024 [Member}
Average contract notional amount			$ 25,000
Weighted average entry rate			5.08%
Average receive rate			4.99%
Open Equity	[2]		$ (24)
Three Month SOFR Futures Ending in June 2025 [Member]
Average contract notional amount		$ 129,000	$ 25,000
Weighted average entry rate		3.77%	3.58%
Average receive rate		3.52%	3.42%
Open Equity	[2]	$ (333)	$ (41)
Three Month SOFR Futures Ending September 2024 [Member]
Average contract notional amount			$ 25,000
Weighted average entry rate			4.67%
Average receive rate			4.52%
Open Equity	[2]		$ (39)
Three Month SOFR Futures Ending in September 2025 [Member]
Average contract notional amount		$ 129,000	$ 25,000
Weighted average entry rate		3.49%	3.37%
Average receive rate		3.21%	3.21%
Open Equity	[2]	$ (356)	$ (39)
Three Month SOFR Futures Ending in December 2025 [Member]
Average contract notional amount		$ 129,000	$ 25,000
Weighted average entry rate		3.31%	3.25%
Average receive rate		3.07%	3.10%
Open Equity	[2]	$ (320)	$ (37)
Three Month SOFR Futures Ending in March 2026 [Member]
Average contract notional amount		$ 129,000	$ 25,000
Weighted average entry rate		3.21%	3.21%
Average receive rate		3.00%	3.07%
Open Equity	[2]	$ (275)	$ (35)
Three Month SOFR Futures Ending in June 2026 [Member]
Average contract notional amount		$ 104,000
Weighted average entry rate		3.15%
Average receive rate		2.97%
Open Equity		$ (178)
Three Month SOFR Futures Ending in September 2026 [Member]
Average contract notional amount		$ 104,000
Weighted average entry rate		3.11%
Average receive rate		2.98%
Open Equity		$ (137)
Three Month SOFR Futures Ending in December 2026 [Member]
Average contract notional amount		$ 29,000
Weighted average entry rate		3.34%
Average receive rate		3.01%
Open Equity		$ (96)
Three Month SOFR Futures Ending in March 2027 [Member]
Average contract notional amount		$ 16,250
Weighted average entry rate		3.10%
Average receive rate		3.04%
Open Equity		$ (10)

[1] 10-Year T-Note futures contracts were valued at a price of $114.28 at September 30, 2024 and $112.89 at December 31, 2023. The contract values of the short positions were $14.3 million and $361.2 million at September 30, 2024 and December 31, 2023, respectively. 5-Year T-Note futures contracts were valued at a price of $108.77 at December 31, 2023. The contract value of the short position was $458.5 million at December 31, 2023.

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