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INVESTMENTS - Schedule of Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024
Total |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | $ 796,222 | $ 704,562
New investments, repayments and settlements: |  |
Issuances/originations | 396,706 | 183,175
Settlements/repayments | (261,907) | (133,641)
Net proceeds from sales | (89,564) | (2,776)
Transfers | 0 | 0
Ending balance | 854,013 | 796,222
Total | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 55,368 | 2,006
Total | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 6,345 | 43,124
Reversal of prior period net depreciation (appreciation) on realization | (49,157) | (228)
Secured First Lien Debt |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | 554,937 | 510,701
New investments, repayments and settlements: |  |
Issuances/originations | 322,603 | 131,462
Settlements/repayments | (240,195) | (80,102)
Net proceeds from sales | 0 | 50
Transfers | (8,500) | 0
Ending balance | 622,371 | 554,937
Secured First Lien Debt | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | (8,513) | (50)
Secured First Lien Debt | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | (7,573) | (7,071)
Reversal of prior period net depreciation (appreciation) on realization | 9,612 | (53)
Secured second lien debt |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | 113,716 | 127,854
New investments, repayments and settlements: |  |
Issuances/originations | 57,958 | 36,978
Settlements/repayments | (21,712) | (53,539)
Net proceeds from sales | 0 | 0
Transfers | 0 | 0
Ending balance | 150,542 | 113,716
Secured second lien debt | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 0 | 0
Secured second lien debt | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 285 | 2,445
Reversal of prior period net depreciation (appreciation) on realization | 295 | (22)
Unsecured debt |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | 32 | 24
New investments, repayments and settlements: |  |
Issuances/originations | 357 | 0
Settlements/repayments | 0 | 0
Net proceeds from sales | 0 | 0
Transfers | 0 | 0
Ending balance | 333 | 32
Unsecured debt | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 0 | 0
Unsecured debt | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | (56) | 8
Reversal of prior period net depreciation (appreciation) on realization | 0 | 0
Preferred equity |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | 31,346 | 26,855
New investments, repayments and settlements: |  |
Issuances/originations | 12,762 | 10,150
Settlements/repayments | 0 | 0
Net proceeds from sales | (19,404) | (1,082)
Transfers | 0 | 0
Ending balance | 31,214 | 31,346
Preferred equity | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | (946) | 332
Preferred equity | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 6,510 | (5,039)
Reversal of prior period net depreciation (appreciation) on realization | 946 | 130
Common Equity/ Equivalents |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Beginning balance | 96,191 | 39,128
New investments, repayments and settlements: |  |
Issuances/originations | 3,026 | 4,585
Settlements/repayments | 0 | 0
Net proceeds from sales | (70,160) | (1,744)
Transfers | 8,500 | 0
Ending balance | 49,553 | 96,191
Common Equity/ Equivalents | Net realized gain (loss) |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 64,827 | 1,724
Common Equity/ Equivalents | Net unrealized appreciation (depreciation) and Reversal of prior period net depreciation (appreciation) on realization |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Total gain (loss) | 7,179 | 52,781
Reversal of prior period net depreciation (appreciation) on realization | $ (60,010) | $ (283)

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