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BORROWINGS - Schedule of Debt (Details) $ in Thousands | Mar. 31, 2025 USD ($) note | Dec. 31, 2024 USD ($) | Mar. 31, 2024 USD ($) note | May 31, 2023 USD ($) | Mar. 31, 2023 USD ($) | Mar. 31, 2022 USD ($) | Aug. 31, 2021 USD ($) | Mar. 31, 2021 USD ($) | Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2018 USD ($) | Mar. 31, 2017 USD ($) | Mar. 31, 2016 USD ($)
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 463,738 |  | $ 404,238 |  | $ 297,688 | $ 267,584 |  | $ 155,434 | $ 54,296 | $ 58,096 | $ 112,096 | $ 74,796 | $ 100,096
Total borrowings | $ 455,709 |  | $ 398,345 |  |  |  |  |  |  |  |  |  |
Indebtedness asset coverage on our senior securities | 204.40% |  | 219.00% |  |  |  |  |  |  |  |  |  |
Notes Payable |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Outstanding | note | 18,549,500 |  | 13,489,500 |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 463,738 |  | $ 337,238 |  |  |  |  |  |  |  |  |  |
Less: Unamortized Discounts | (8,029) |  | (5,893) |  |  |  |  |  |  |  |  |  |
Total borrowings | $ 455,709 |  | $ 331,345 |  |  |  |  |  |  |  |  |  |
Notes Payable | 5.00% Notes Due 2026 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate | 5.00% |  | 5.00% |  |  |  |  | 5.00% |  |  |  |  |
Notes Outstanding | note | 5,117,500 |  | 5,117,500 |  |  |  |  |  |  |  |  |  |
Principal Amount per Note | 25.00 |  | 25.00 |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 127,938 |  | $ 127,938 |  |  |  |  | $ 127,900 |  |  |  |  |
Notes Payable | 4.875% Notes due 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate | 4.875% |  | 4.875% |  |  |  | 4.875% |  |  |  |  |  |
Notes Outstanding | note | 5,382,000 |  | 5,382,000 |  |  |  |  |  |  |  |  |  |
Principal Amount per Note | 25.00 |  | 25.00 |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 134,550 |  | $ 134,550 |  |  |  | $ 134,600 |  |  |  |  |  |
Notes Payable | 8.00% Notes due 2028 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate | 8.00% |  | 8.00% | 8.00% |  |  |  |  |  |  |  |  |
Notes Outstanding | note | 2,990,000 |  | 2,990,000 |  |  |  |  |  |  |  |  |  |
Principal Amount per Note | 25.00 |  | 25.00 |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 74,750 |  | $ 74,750 | $ 74,800 |  |  |  |  |  |  |  |  |
Notes Payable | 7.875% Notes Due 2030 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Interest Rate | 7.875% | 7.875% |  |  |  |  |  |  |  |  |  |  |
Notes Outstanding | note | 5,060,000 |  |  |  |  |  |  |  |  |  |  |  |
Principal Amount per Note | 25.00 |  |  |  |  |  |  |  |  |  |  |  |
Aggregate Principal Amount | $ 126,500 | $ 126,500 |  |  |  |  |  |  |  |  |  |  |

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