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DISTRIBUTIONS TO COMMON STOCKHOLDERS - Narrative (Details) - USD ($) | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Mar. 31, 2025 | Dec. 31, 2024
Equity [Abstract] |  |  |  |  |  |
Investment company, cash distributions paid to common stockholders from ordinary income | 51.30% |  | 51.30% |  |  | 52.90%
Investment company, cash distributions paid to common stockholders from capital gains | 48.70% |  | 48.70% |  |  | 47.10%
Cash distributions to common stockholders |  |  | $ 38,100,000 | $ 43,300,000 |  |
Payments of dividends |  |  |  | 17,600,000 |  |
Distributions payable | $ 0 | $ 25,682,000 | 0 | 25,682,000 |  |
Investment company, distributions paid subsequent to fiscal year-end, classified in prior year, ordinary income |  |  |  |  | $ 36,700,000 |
Investment company, distribution paid subsequent to fiscal year-end, classified in prior year, capital gains |  |  |  |  | $ 18,700,000 |
Investment company, net adjustments for tax difference to capital distribution | $ 2,200 | $ 600,000 | $ 300,000 | $ 800,000 |  |

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