v3.26.1
Borrowings - Narrative (Details)
12 Months Ended
Aug. 16, 2027
Mar. 29, 2027
Mar. 28, 2027
Sep. 30, 2025
USD ($)
portfolioCompany
Sep. 29, 2025
Jun. 20, 2025
USD ($)
Jun. 13, 2025
Jun. 12, 2025
Aug. 15, 2024
Mar. 28, 2024
Sep. 30, 2025
USD ($)
portfolioCompany
Sep. 30, 2024
USD ($)
Sep. 30, 2023
USD ($)
Jun. 03, 2025
USD ($)
Jun. 02, 2025
USD ($)
Sep. 30, 2022
Apr. 02, 2022
Debt Instrument [Line Items]                                  
Minimum asset coverage ratio required                                 1.50
Asset coverage ratio       188.47%             188.47% 192.32% 201.79%     206.27%  
Investments, at fair value       $ 2,209,174,000 [1]             $ 2,209,174,000 [1] $ 1,311,001,000 [2]          
Outstanding debt       1,181,274,000             1,181,274,000 684,114,000          
Other short-term borrowings       $ 0             0 0          
Average outstanding balance                     $ 939,931,000 $ 465,362,000 $ 101,802,000        
Annualized average stated interest rate                     6.90% 8.20% 7.10%        
2025 Debt Securitization                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           $ 1,154,900,000                      
Number of investment portfolio company | portfolioCompany       126             126            
Investments, at fair value       $ 1,139,381,000             $ 1,139,381,000            
Annualized average stated interest rate                     6.10%            
2025 Debt Securitization | Subordinated Debt                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           286,650,000                      
2025 Debt Securitization | Class A-1 2025 Notes                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           $ 667,000,000                      
Debt instrument, basis spread on variable rate       1.63%   1.63%                      
Outstanding debt       $ 667,000,000             $ 667,000,000            
2025 Debt Securitization | Class A-2 2025 Notes                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           $ 40,250,000                      
Debt instrument, basis spread on variable rate       1.80%   1.80%                      
Outstanding debt       $ 40,250,000             40,250,000            
2025 Debt Securitization | Class B 2025 Notes                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           $ 92,000,000                      
Debt instrument, basis spread on variable rate       2.00%   2.00%                      
Outstanding debt       $ 92,000,000             $ 92,000,000            
2025 Debt Securitization | Class C Notes                                  
Debt Instrument [Line Items]                                  
Debt instrument, face amount           $ 69,000,000                      
Debt instrument, basis spread on variable rate           2.80%                      
PNC Facility                                  
Debt Instrument [Line Items]                                  
Annualized average stated interest rate                     6.70% 7.70% 6.80%        
PNC Facility | Line of Credit | Revolving Credit Facility                                  
Debt Instrument [Line Items]                                  
Line of credit facility, maximum borrowing capacity                           $ 100,000,000 $ 250,000,000    
Outstanding debt                       $ 240,428,000          
PNC Facility | Line of Credit | Revolving Credit Facility | Minimum                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate         2.15%                        
PNC Facility | Line of Credit | Revolving Credit Facility | Maximum                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate         2.45%                        
DB Credit Facility                                  
Debt Instrument [Line Items]                                  
Annualized average stated interest rate                     6.50% 7.70%          
DB Credit Facility | Sterling Overnight Index Average                                  
Debt Instrument [Line Items]                                  
Debt instrument, credit spread adjustment                   0.1193%              
DB Credit Facility | Line of Credit | Revolving Credit Facility                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate             1.75% 2.35%                  
Line of credit facility, maximum borrowing capacity       300,000,000             $ 300,000,000            
Outstanding debt       $ 198,117,000             $ 198,117,000 $ 299,557,000          
Debt instrument, term                   3 years              
Line of credit facility, non-usage fee, percentage                   0.25%              
Line of credit facility, prepayment fee, year one, percentage                   0.50%              
Line of credit facility, prepayment fee, year two, percentage                   0.25%              
DB Credit Facility | Line of Credit | Revolving Credit Facility | Forecast                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate   2.25% 2.85%                            
DB Credit Facility | Line of Credit | Revolving Credit Facility | Base Rate                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate       1.75%                          
DB Credit Facility | Line of Credit | Revolving Credit Facility | Base Rate | Forecast                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate   2.25%                              
DB Credit Facility | Line of Credit | Revolving Credit Facility | Canadian Overnight Repo Rate Average                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate                   0.32138%              
BNP Credit Facility                                  
Debt Instrument [Line Items]                                  
Annualized average stated interest rate                     6.30% 7.30%          
BNP Credit Facility | Line of Credit | Revolving Credit Facility                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate       0.15%                          
Line of credit facility, maximum borrowing capacity       $ 750,000,000             $ 750,000,000            
Outstanding debt       $ 192,188,000             $ 192,188,000 $ 152,000,000          
Debt instrument, term                 36 months                
BNP Credit Facility | Line of Credit | Revolving Credit Facility | Base Rate                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate       2.10%                          
BNP Credit Facility | Line of Credit | Revolving Credit Facility | Base Rate | Forecast                                  
Debt Instrument [Line Items]                                  
Debt instrument, basis spread on variable rate 2.35%                                
Adviser Revolver                                  
Debt Instrument [Line Items]                                  
Annualized average stated interest rate                     4.10% 5.00% 5.00%        
Adviser Revolver | Revolving Credit Facility | Short-term Applicable Federal Rate                                  
Debt Instrument [Line Items]                                  
Debt instrument, interest rate, stated percentage       3.90%             3.90%            
Adviser Revolver | Line of Credit | Revolving Credit Facility                                  
Debt Instrument [Line Items]                                  
Line of credit facility, maximum borrowing capacity       $ 100,000,000             $ 100,000,000 $ 100,000,000          
Outstanding debt       $ 0             $ 0 $ 0          
[1] The fair values of investments were valued using significant unobservable inputs, unless otherwise noted. See Note 7. The fair value of loan investments may include the impact of the unfunded commitment being valued below par.
[2] The fair values of investments were valued using significant unobservable inputs, unless otherwise noted. See Note 7. The fair value of loan investments may include the impact of the unfunded commitment being valued below par.