v3.26.1
Fair Value Measurements - Schedule of Fair Value, Assets Measured on Recurring Basis (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Sep. 30, 2024
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value $ 2,209,174 [1] $ 1,311,001 [2]
Money market funds 46,041 20,893
Total assets, at fair value: 2,255,215 1,331,894
Forward currency contracts (864)  
Total liabilities, at fair value: (864)  
Level 1    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Money market funds 46,041 [1] 20,893
Total assets, at fair value: 46,041 20,893
Forward currency contracts 0  
Total liabilities, at fair value: 0  
Level 2    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Money market funds 0 0
Total assets, at fair value: 0 0
Forward currency contracts (864)  
Total liabilities, at fair value: (864)  
Level 3    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Money market funds 0 0
Total assets, at fair value: 2,209,174 1,311,001
Forward currency contracts 0  
Total liabilities, at fair value: 0  
Debt Investments    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 2,174,044 1,294,931
Debt Investments | Level 1    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 0 0
Debt Investments | Level 2    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 0 0
Debt Investments | Level 3    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 2,174,044 1,294,931
Equity Investments    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 35,130 16,070
Equity Investments | Level 1    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 0 0
Equity Investments | Level 2    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value 0 0
Equity Investments | Level 3    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Fair Value $ 35,130 $ 16,070
[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.