v3.26.1
Borrowings - GBDC 3 DB Credit Facility (Details) - Revolving Credit Facility - GBDC 3 DB Credit Facility - Line of Credit
$ in Thousands
 6 Months Ended
Nov. 18, 2024
USD ($)
Debt Instrument [Line Items]  
Line of credit facility, maximum borrowing capacity $ 625,000
Line of credit facility, commitment fee percentage 0.06944%
Line of credit facility, non-usage fee, percentage 0.25%
Line of credit facility, prepayment fee, first year after effective date, percentage 0.50%
Line of credit facility, prepayment fee, second year after effective date, percentage 0.25%
Base Rate  
Debt Instrument [Line Items]  
Line of credit facility, interest rate during period 2.30%
Line of credit facility, interest rate at period end 2.80%
Canadian Overnight Repo Rate Average  
Debt Instrument [Line Items]  
Debt instrument, basis spread on variable rate 0.32138%