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INVESTMENT IN RELATED PARTY INVESTMENT FUND - Schedule of Summarized Statements of Assets, Liabilities and Net Assets of SILP (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Expenses |  |  |  |
Interest | $ (1,144) | $ (1,560) | $ (2,608) | $ (2,809)
Total expenses | (159,431) | (166,450) | (341,824) | (330,225)
Net investment income (loss) | 10,470 | 10,948 | 18,757 | 24,126
Realized and change in unrealized gains (losses) |  |  |  |
Net gain (loss) on investment transactions | 33 | 89 | 144 | (324)
Net increase in Partners' capital | 329 | 7,978 | 29,956 | 34,997
Income (loss) from investment in related party investment fund (Note 3) | (18,276) | 4,330 | 13,921 | 22,578
Management fees | 1,756 | 1,408 | 3,486 | 2,731
Performance allocation | (2,031) | 481 | 1,547 | 2,509
Total | (275) | 1,889 | 5,033 | 5,240
Solasglas Investments, LP (SILP) |  |  |  |
Realized and change in unrealized gains (losses) |  |  |  |
Income (loss) from investment in related party investment fund (Note 3) | (18,276) | 4,330 | 13,921 | 22,578
Solasglas Investments, LP (SILP) |  |  |  |
Investment income |  |  |  |
Dividend income (net of withholding taxes) | 2,687 | 941 | 4,177 | 1,772
Interest income | 4,822 | 2,148 | 8,449 | 6,500
Total Investment income | 7,509 | 3,089 | 12,626 | 8,272
Expenses |  |  |  |
Management fee | (1,756) | (1,408) | (3,486) | (2,731)
Interest | (3,770) | (736) | (5,471) | (2,070)
Dividends | (916) | (731) | (1,677) | (1,435)
Research and operating | (486) | (335) | (971) | (659)
Total expenses | (6,928) | (3,210) | (11,605) | (6,895)
Net investment income (loss) | 581 | (121) | 1,021 | 1,377
Realized and change in unrealized gains (losses) |  |  |  |
Net realized gain | 36,584 | 20,085 | 55,689 | 63,030
Net change in unrealized appreciation (depreciation) | (62,256) | (13,138) | (35,238) | (29,383)
Net gain (loss) on investment transactions | (25,672) | 6,947 | 20,451 | 33,647
Net increase in Partners' capital | $ (25,091) | $ 6,826 | $ 21,472 | $ 35,024

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