v3.25.4
Organization - Additional Information (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Dec. 31, 2022
Jan. 31, 2022
Oct. 31, 2021
Apr. 30, 2021
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Debt Instrument [Line Items]              
Holding transferred 100.00%            
Net realized gain (loss) on investments         $ (52,460) $ (33,833) $ (151,516)
PennantPark-TSO Senior Loan Fund II, LP              
Debt Instrument [Line Items]              
Sale of investments to wholly owned subsidiary   $ 82,300          
Sale of investments to wholly owned subsidiary in cash   75,700          
Sale of investments to wholly owned subsidiary in equity interest   $ 6,600          
Percentage of outstanding class A units   23.10%     23.10%    
Net realized gain (loss) on investments   $ 200          
Capital commitment         $ 15,000    
Funded percentage         100.00%    
Voting interest in general partnership         4.99%    
2026 Notes              
Debt Instrument [Line Items]              
Aggregate principal amount of notes issued       $ 150,000      
Percentage of public offering price per notes issued       99.40%      
Debt instrument, maturity date       May 01, 2026      
Debt instrument, periodic payment       semi-annually      
Debt instrument, interest rate       4.50%      
Basis points       4.62      
2026 Notes-2              
Debt Instrument [Line Items]              
Aggregate principal amount of notes issued     $ 165,000        
Percentage of public offering price per notes issued     99.40%        
Debt instrument, maturity date     Nov. 01, 2026        
Debt instrument, periodic payment     semi-annually        
Debt instrument, interest rate     4.00%        
Basis points     4.12