Note 4 - Investments - Cash Flows (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Investments, net | $ (44.8) | $ (9.9) |
| Seeded Investment Products [Member] | ||
| Purchases and settlements | (204.2) | (41.1) |
| Sales, settlements and maturities | 22.5 | 3.0 |
| Investments, net | (181.7) | (38.1) |
| Securities Investment [Member] | ||
| Purchases and settlements | (119.1) | (65.7) |
| Sales, settlements and maturities | 74.3 | 55.8 |
| Investments, net | $ (44.8) | $ (9.9) |