Quarterly report [Sections 13 or 15(d)]

BORROWINGS - Schedule of Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details)

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BORROWINGS - Schedule of Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Sep. 30, 2024
Debt Instrument [Line Items]          
Credit Facility $ 27,500   $ 27,500   $ 70,600
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring          
Debt Instrument [Line Items]          
Credit Facility 27,500   27,500   $ 70,600
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Long-Term Debt          
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]          
Beginning balance 25,149 $ 117,200 70,600 $ 47,800  
Borrowings 63,500 45,200 212,000 179,500  
Repayments (61,100) (96,600) (255,100) (161,500)  
Net unrealized appreciation (49) 0 0 0  
Ending balance $ 27,500 $ 65,800 $ 27,500 $ 65,800