Note 5 - Derivative and Other Hedging Instruments - Schedule of Derivative Instruments Gain (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
(Losses) gains on derivative and other hedging instruments	$ (53,286)	$ 26,068	$ (127,945)	$ 113,967
Treasury Note Future [Member] | Short [Member]
(Losses) gains on derivative and other hedging instruments	(8,688)	11,678	(23,630)	30,768
Interest Rate Swap [Member]
(Losses) gains on derivative and other hedging instruments	(37,408)	11,518	(100,251)	70,616
Payer Swaptions [Member] | Short [Member]
(Losses) gains on derivative and other hedging instruments	0	(14)	0	(72)
Dual Digital Option [Member]
(Losses) gains on derivative and other hedging instruments	0	(156)	0	(395)
TBA Contracts [Member] | Short [Member]
(Losses) gains on derivative and other hedging instruments	(7,662)	3,042	(4,636)	12,945
TBA Contracts [Member] | Long [Member]
(Losses) gains on derivative and other hedging instruments	$ 472	$ 0	$ 572	$ 105