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Note 5 - Transactions With Affiliated Companies - Investments in Controlled Affiliated Companies (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Investments, fair value | $ 697,891 |
Net unrealized appreciation (depreciation) on investments | (32,156) | $ (3,960)
Net realized gain (loss) | 1 | 8
Investments, fair value | 689,553 |
Interest Income, Operating, Paid in Kind | 285 | 1,382
Investment, Affiliated Issuer, Noncontrolled [Member] |  |
Investments, fair value | 8,307 | 1,132
Purchases | 2 | 15
Reductions | 0 | 0
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 0 | 0
Net unrealized appreciation (depreciation) on investments | (2) | 11,433
Net realized gain (loss) | 0 | (3)
Investments, fair value | 8,307 | 12,577
Interest Income, Net | 0 | 0
Investment, Affiliated Issuer, Noncontrolled [Member] | Aulea Medical, Inc. [Member] |  |
Investments, fair value | 0 | 0
Purchases | 0 | 3
Reductions | 0 | 0
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 0 | 0
Net unrealized appreciation (depreciation) on investments | 0 | 0
Net realized gain (loss) | 0 | (3)
Investments, fair value | 0 | 0
Interest Income, Net | 0 | 0
Investment, Affiliated Issuer, Noncontrolled [Member] | Evelo Biosciences, Inc. [Member] |  |
Investments, fair value | 8,307 | 1,132
Purchases | 2 | 12
Reductions | 0 | 0
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 0 | 0
Net unrealized appreciation (depreciation) on investments | (2) | 11,433
Net realized gain (loss) | 0 | 0
Investments, fair value | 8,307 | 12,577
Interest Income, Net | 0 | 0
Investment, Affiliated Issuer, Controlled [Member] |  |
Investments, fair value | 31,819 | 14,223
Purchases | 2,950 | 977
Reductions | 0 | (547)
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 9 | 4
Net unrealized appreciation (depreciation) on investments | (20,117) | (1,179)
Net realized gain (loss) | 0 | 0
Investments, fair value | 14,869 | 13,644
Interest Income, Net | (61) | 177
Interest Income, Operating, Paid in Kind | 208 | 166
Investment, Affiliated Issuer, Controlled [Member] | Better Place Forests Co. [Member] |  |
Investments, fair value | 0 | 7,993
Purchases | 941 | 750
Reductions | 0 | 0
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 0 | 4
Net unrealized appreciation (depreciation) on investments | (62) | (1,114)
Net realized gain (loss) | 0 | 0
Investments, fair value | 879 | 7,799
Interest Income, Net | 0 | 177
Interest Income, Operating, Paid in Kind | 0 | 166
Investment, Affiliated Issuer, Controlled [Member] | HIMV LLC [Member] |  |
Investments, fair value | 6,230 | 6,230
Purchases | 0 | 227
Reductions | 0 | (547)
Transfers in/(out) at fair value | 0 | 0
Discount accretion | 0 | 0
Net unrealized appreciation (depreciation) on investments | (940) | (65)
Net realized gain (loss) | 0 | 0
Investments, fair value | 5,290 | 5,845
Interest Income, Net | 0 | 0
Interest Income, Operating, Paid in Kind | 0 | $ 0
Investment, Affiliated Issuer, Controlled [Member] | Nexii Building Solutions, Inc [Member] |  |
Investments, fair value | 8,547 |
Purchases | 0 |
Reductions | 0 |
Transfers in/(out) at fair value | 0 |
Discount accretion | 0 |
Net unrealized appreciation (depreciation) on investments | 153 |
Net realized gain (loss) | 0 |
Investments, fair value | 8,700 |
Interest Income, Net | 20 |
Interest Income, Operating, Paid in Kind | 0 |
Investment, Affiliated Issuer, Controlled [Member] | Swift Health Systems Inc. [Member] |  |
Investments, fair value | 17,042 |
Purchases | 2,009 |
Reductions | 0 |
Transfers in/(out) at fair value | 0 |
Discount accretion | 9 |
Net unrealized appreciation (depreciation) on investments | (19,268) |
Net realized gain (loss) | 0 |
Investments, fair value | 0 |
Interest Income, Net | (81) |
Interest Income, Operating, Paid in Kind | $ 208 |

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