Note 7 - Offsetting Assets and Liabilities - Offsetting Liabilities (Details) - Liability [Member] - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Gross amount, recognized	$ 4,346,548	$ 3,718,343
Gross Amount, offset	0	0
Net Amount	4,346,548	3,718,343
Gross Amount, not recognized	(4,334,519)	(3,705,649)
Gross amount, not offset	(12,029)	(12,694)
Net amount, after deduction	0	0
Repurchase Agreements [Member]
Gross amount, recognized	4,345,704	3,705,649
Gross Amount, offset	0	0
Net Amount	4,345,704	3,705,649
Gross Amount, not recognized	(4,334,519)	(3,705,649)
Gross amount, not offset	(11,185)	0
Net amount, after deduction	0	0
TBA Contracts [Member]
Gross amount, recognized	844	12,694
Gross Amount, offset	0	0
Net Amount	844	12,694
Gross Amount, not recognized	0	0
Gross amount, not offset	(844)	(12,694)
Net amount, after deduction	$ 0	$ 0