Note 4 - Investments (Details Textual) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Debt Securities, Trading, Unrealized Gain (Loss) | $ 61.5 | $ 35.6 |
| European Smaller Companies Trust PLC [Member] | ||
| Other Investments | $ 53.7 | |
| Privacore [Member] | ||
| Equity Method Investment, Ownership Percentage | 49.00% | |
| Long Tail Alpha Investment [Member] | ||
| Equity Method Investment, Ownership Percentage | 20.00% | |
| X | ||||||||||
- Definition Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading). Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of investments classified as other. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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