v3.25.2
Borrowings - GBDC 3 2022 Debt Securitization (Narrative) (Details)
$ in Thousands
4 Months Ended 9 Months Ended
Jun. 03, 2024
USD ($)
Sep. 30, 2024
USD ($)
portfolioCompany
Jun. 30, 2025
USD ($)
portfolioCompany
Debt Instrument [Line Items]      
Investments, at fair value   $ 8,235,411 [1] $ 8,961,549 [2]
GBDC 3 2022 Debt Securitization      
Debt Instrument [Line Items]      
Debt instrument, face amount $ 401,750    
Debt instrument, basis spread on variable rate     4.30%
Repayments of debt   $ 14,751  
Number of investment portfolio company | portfolioCompany   55 47
Investments, at fair value   $ 377,755 $ 293,120
GBDC 3 2022 Debt Securitization | Subordinated debt      
Debt Instrument [Line Items]      
Debt instrument, face amount 149,750    
GBDC 3 2022 Debt Securitization | Class A Senior Secured Floating Rate Notes      
Debt Instrument [Line Items]      
Debt instrument, face amount $ 252,000    
Debt instrument, basis spread on variable rate 2.00%    
[1] The fair values of investments were valued using significant unobservable inputs, unless noted otherwise. See Note 6.
[2] The fair values of investments were valued using significant unobservable inputs, unless noted otherwise. See Note 6.