v3.26.3
Revolving Credit Facility - Narrative (Details) - USD ($)
 3 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Line of Credit Facility [Line Items]      
Credit facility outstanding balance $ 287,152,000   $ 562,328,000
Debt financing costs $ 12,940,000   14,128,000
Investments Held Benchmark | Net Assets | Affiliated Entity | Prospect Capital Funding LLC      
Line of Credit Facility [Line Items]      
Percentage of total assets at fair value 33.50%    
Revolving Credit Facility | Credit Facility      
Line of Credit Facility [Line Items]      
Maximum borrowing capacity $ 2,121,500,000    
Accordion feature, increase limit $ 2,250,000,000    
Basis spread 2.05%    
Collateralized financings $ 2,003,998,000    
Remaining borrowing capacity 777,956,000   623,891,000
Credit facility outstanding balance 287,152,000   562,328,000
Debt issuance costs, gross 38,278,000    
Debt financing costs 12,940,000   $ 14,128,000
Interest expense $ 14,507,000 $ 18,411,000  
Revolving Credit Facility | Credit Facility | More than 60% Drawn      
Line of Credit Facility [Line Items]      
Unused capacity fee rate 0.40%    
Revolving Credit Facility | Credit Facility | More Than 35% and An Amount Less Than or Equal to 60%      
Line of Credit Facility [Line Items]      
Unused capacity fee rate 0.70%    
Revolving Credit Facility | Credit Facility | Less Than 35% or Equal to 35%      
Line of Credit Facility [Line Items]      
Unused capacity fee rate 1.50%