Quarterly report pursuant to Section 13 or 15(d)

SUBSEQUENT EVENTS - Narrative (Details)

v3.23.3
SUBSEQUENT EVENTS - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Oct. 30, 2023
Apr. 10, 2023
Mar. 08, 2021
Oct. 31, 2023
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2023
Sep. 30, 2022
Mar. 31, 2023
Oct. 29, 2023
Subsequent Event [Line Items]                    
Purchase of investments             $ 114,788 $ 102,046    
Cost         $ 834,798   834,798   $ 720,630 [1]  
Success fee income         0 $ 1,733 0 6,733    
Principal repayments of investments             $ 0 $ 48,000    
Revolving Line of Credit | Line of Credit                    
Subsequent Event [Line Items]                    
Unused fee percentage                 1.00%  
Credit Facility                    
Subsequent Event [Line Items]                    
Term     2 years              
Credit Facility | Line of Credit                    
Subsequent Event [Line Items]                    
Unused fee percentage             0.75%      
Credit Facility | Revolving Line of Credit | Line of Credit                    
Subsequent Event [Line Items]                    
Commitment amount         $ 180,000   $ 180,000   $ 180,000  
Credit Facility | Revolving Line of Credit | Line of Credit | Less than or Equal to 50% of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage             0.50%      
Credit Facility | Revolving Line of Credit | Line of Credit | Greater Than 50% But Less Than or Equal to 65% of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage             0.75%      
Credit Facility | Revolving Line of Credit | Line of Credit | Greater Than 65% Of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage             1.00%      
Credit Facility | Revolving Line of Credit | Line of Credit | Secured Overnight Financing Rate (SOFR)                    
Subsequent Event [Line Items]                    
Debt instrument, variable rate floor             0.35%   0.50%  
Debt instrument, basis spread on variable rate   0.11%         3.25%      
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche One                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate             2.85%      
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche Two                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate             3.10%      
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Thereafter                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate             3.35%      
Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Thereafter, Adjustment                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate             0.11%      
Subsequent Event | Credit Facility                    
Subsequent Event [Line Items]                    
Term 2 years                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit                    
Subsequent Event [Line Items]                    
Commitment amount $ 135,000                 $ 180,000
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | Less than or Equal to 50% of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage 0.50%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | Greater Than 50% But Less Than or Equal to 65% of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage 0.75%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | Greater Than 65% Of Commitment                    
Subsequent Event [Line Items]                    
Unused fee percentage 1.00%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | Secured Overnight Financing Rate (SOFR)                    
Subsequent Event [Line Items]                    
Debt instrument, variable rate floor 0.35%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche One                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate 3.15%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Tranche Two                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate 3.40%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Thereafter                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate 3.65%                  
Subsequent Event | Credit Facility | Revolving Line of Credit | Line of Credit | SOFR, Thereafter, Adjustment                    
Subsequent Event [Line Items]                    
Debt instrument, basis spread on variable rate 0.10%                  
Subsequent Event | SFEG Holdings, Inc                    
Subsequent Event [Line Items]                    
Purchase of investments       $ 64,700            
Cost       4,800            
Subsequent Event | Counsel Press, Inc.,                    
Subsequent Event [Line Items]                    
Success fee income       1,400            
Realized gain on preferred equity       43,500            
Principal repayments of investments       $ 27,500            
[1] Cumulative gross unrealized appreciation for federal income tax purposes is $150.4 million; cumulative gross unrealized depreciation for federal income tax purposes is $119.3 million. Cumulative net unrealized appreciation is $31.1 million, based on a tax cost of $722.4 million.