Note 2 - Mortgage-backed Securities, at Fair Value (Details Textual) - USD ($) $ in Thousands |
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2025 |
|
| Notional Balance, Interest Only Securities Portfolio, Amount | $ 66,100 | $ 72,900 | |
| Notional Balance, Inverse Interest Only Securities Portfolio, Amount | 12,800 | $ 17,700 | |
| Investment Sold at Carrying Value | (768,857) | $ (743,192) | |
| Collateralized Mortgage-Backed Securities [Member] | |||
| Investment Sold at Carrying Value | $ 413,300 | ||