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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands | 6 Months Ended |
--- | --- | ---
Sep. 30, 2025 USD ($) segment | Mar. 31, 2025 USD ($)
Summary of Investment Holdings [Line Items] |  |  |
Investments, cost | $ 1,037,200 | $ 939,066 | [1]
Investments at fair value | $ 1,130,859 | 979,320 | [1]
Number of reportable segments | segment | 1 |  |
B+T Group Acquisition, Inc. ("B+T"), Diligent Delivery Systems ("Diligent") and Edge Adhesives Holdings, Inc. ("Edge") |  |  |
Summary of Investment Holdings [Line Items] |  |  |
Investments, cost | $ 40,300 |  |
Cost percentage | 5.50% |  |
Investments at fair value | $ 18,700 |  |
Fair value percentage | 2.70% |  |
B+T, Diligent, Edge and J.R. Hobbs Co. – Atlanta, LLC (“J.R. Hobbs”) |  |  |
Summary of Investment Holdings [Line Items] |  |  |
Investments, cost |  | $ 90,200 |
Cost percentage |  | 13.10% |
Investments at fair value |  | $ 50,900 |
Fair value percentage |  | 8.20% |
[1] | Cumulative gross unrealized appreciation for federal income tax purposes is $183.3 million; cumulative gross unrealized depreciation for federal income tax purposes is $144.9 million. Cumulative net unrealized appreciation is $38.5 million, based on a tax cost of $940.9 million.

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