Note 5 - Derivative and Other Hedging Instruments - Schedule of Derivative Positions (Details) - Short [Member] - USD ($) $ in Thousands		Mar. 31, 2025	Dec. 31, 2024
Five Year Treasury Note Futures [Member]
Average contract notional amount	[1]	$ 377,500	$ 312,500	[2]
Weighted average entry rate	[1]	4.16%	4.22%
Average receive rate	[1]	3.94%	4.37%
Open Equity	[1],[3]	$ (3,371)	$ 1,890
Ten Year T-Note Futures [Member]
Average contract notional amount		$ 193,500	$ 93,500
Weighted average entry rate		4.23%	4.30%
Average receive rate		4.09%	4.49%
Open Equity		$ (1,692)	$ 1,119
Ten Year Ultra Futures [Member]
Average contract notional amount		$ 137,500	$ 32,500
Weighted average entry rate		4.37%	4.25%
Average receive rate		4.24%	4.58%
Open Equity		$ (1,611)	$ 914
Three Month SOFR Futures, Ending June 2024 [Member}
Average contract notional amount		$ 28,750
Weighted average entry rate		4.05%
Average receive rate		4.08%
Open Equity	[3]	$ 9
Three Month SOFR Futures Ending September 2024 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.83%
Average receive rate		3.81%
Open Equity	[3]	$ (4)
Three Month SOFR Futures Ending in December 2024 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.69%
Average receive rate		3.63%
Open Equity	[3]	$ (19)
Three Month SOFR Futures Ending in March 2025 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.61%
Average receive rate		3.51%
Open Equity	[3]	$ (29)
Three Month SOFR Futures Ending in June 2025 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.57%
Average receive rate		3.44%
Open Equity	[3]	$ (35)
Three Month SOFR Futures Ending in September 2025 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.55%
Average receive rate		3.43%
Open Equity	[3]	$ (37)
Three Month SOFR Futures Ending in December 2025 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.56%
Average receive rate		3.44%
Open Equity	[3]	$ (35)
Three Month SOFR Futures Ending in March 2026 [Member]
Average contract notional amount		$ 28,750
Weighted average entry rate		3.56%
Average receive rate		3.46%
Open Equity	[3]	$ (30)

[1] 5-Year T-Note futures contracts were valued at a price of $108.16 at March 31, 2025 and $106.30 at December 31, 2024. The contract values of the short positions were $408.3 million and $332.2 million at March 31, 2025 and December 31, 2024, respectively. 10-Year T-Note futures contracts were valued at a price of $111.22 at March 31, 2025 and $108.75 at December 31, 2024. The contract values of the short positions were $215.2 million and $101.6 million at March 31, 2025 and December 31, 2024, respectively. 10-Year Ultra futures contracts were valued at a price of $114.13 at March 31, 2025 and $111.31 at December 31, 2024. The contract values of the short positions were $156.9 million and $36.2 million at March 31, 2025 and December 31, 2024, respectively.

[2] 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.

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