Note 5 - Derivative and Other Hedging Instruments - Schedule of Derivative Instruments in Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Restricted Cash and Cash Equivalents, Current	$ 119,614	$ 31,568
Other liabilities	(14,888)	(25,119)
Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative assets, at fair value	20,605	40,172
Derivative liabilities, at fair value	2,731	7,161
Total margin balances on derivative contracts	(6,305)	5,206
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Swap [Member]
Derivative assets, at fair value	5,286	4,983
Not Designated as Hedging Instrument, Economic Hedge [Member] | Payer Swaptions [Member] | Long [Member]
Derivative assets, at fair value	1,418	33,398
Not Designated as Hedging Instrument, Economic Hedge [Member] | Payer Swaptions [Member] | Short [Member]
Derivative liabilities, at fair value	0	5,982
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Cap [Member]
Derivative assets, at fair value	704	1,119
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Floor [Member]
Derivative assets, at fair value	3,981	0
Derivative liabilities, at fair value	2,500	0
Not Designated as Hedging Instrument, Economic Hedge [Member] | TBA Contracts [Member]
Derivative assets, at fair value	9,216	672
Derivative liabilities, at fair value	231	1,179
Restricted Cash and Cash Equivalents, Current	1,670	1,734
Other liabilities	(11,052)	(532)
Not Designated as Hedging Instrument, Economic Hedge [Member] | Eurodollar Future Margin [Member]
Restricted Cash and Cash Equivalents, Current	3,067	16,493
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Rate Swaption [Member]
Restricted Cash and Cash Equivalents, Current	1,530	0
Other liabilities	$ (1,520)	$ (12,489)