Note 5 - Derivative and Other Hedging Instruments (Details Textual) - Short [Member] $ in Thousands		Jun. 30, 2025 USD ($) $ / item	Dec. 31, 2024 USD ($) $ / item
Five Year Treasury Note Futures [Member]
Derivative, Forward Price (in USD per Per Share) | $ / item		109	106.3
Derivative, Fair Value, Net		$ 531,400	$ 332,200
Ten Year T-Note Futures [Member]
Derivative, Forward Price (in USD per Per Share) | $ / item		112.13	108.75
Derivative, Fair Value, Net		$ 256,200	$ 101,700
Ten Year Ultra Futures [Member]
Derivative, Forward Price (in USD per Per Share) | $ / item		114.27	111.31
Derivative, Fair Value, Net		$ 225,700	$ 36,200
TBA Contracts [Member]
Derivative, Fair Value, Net	[1]		(4,371)
Derivative Asset, Notional Amount		$ 0	$ 150,000	[2]

[1] Net carrying value represents the difference between the market value and the cost basis of the TBA securities as of period-end and is reported in derivative assets (liabilities), at fair value in the balance sheets.

[2] Notional amount represents the par value (or principal balance) of the underlying Agency RMBS.