Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Pledged assets, Mortgage-backed securities	$ 11,338,541	$ 10,628,658
U.S. Treasury securities, available for sale, amortized cost	154,956	134,715
Pledged assets, available for sale	$ 155,095	$ 135,133
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)	400,000,000	400,000,000
Common stock, issued (in shares)	196,700,226	181,985,900
Common stock, outstanding (in shares)	196,700,226	181,985,900
Asset Pledged as Collateral [Member]
Pledged assets, Mortgage-backed securities	$ 11,259,049	$ 10,502,743
Pledged assets, available for sale	$ 149,585	$ 135,133