Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Pledged assets, Mortgage-backed securities	$ 6,738,094	$ 5,253,310
U.S. Treasury securities, available for sale, amortized cost	125,154	100,412
Pledged assets, available for sale	$ 125,543	$ 100,551
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	20,000,000	20,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	107,786,614	82,622,464
Common stock, outstanding (in shares)	107,786,614	82,622,464
Asset Pledged as Collateral [Member]
Pledged assets, Mortgage-backed securities	$ 6,692,991	$ 5,209,068
Pledged assets, available for sale	$ 120,581	$ 100,551