v3.26.1
Taxable/Distributable Income and Dividend Distributions - Narrative (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2025
Investments, Owned, Federal Income Tax Note [Line Items]          
Undistributed ordinary income, net         $ 699,900
Valuation allowance $ 9,400   $ 9,400    
Deferred income tax expense (benefit)     (205) $ 269  
Income tax expense 300   600    
Cost of investments         3,088,800
Unrealized appreciation         758,800
Unrealized depreciation         1,000,600
Unrealized appreciation (depreciation)         241,800
Net Investment Income          
Investments, Owned, Federal Income Tax Note [Line Items]          
Deferred income tax expense (benefit) (200)   (200)    
Income tax expense 300 $ 100 300 600  
Current income tax $ 500   $ 800    
Realized and Unrealized Gains (Losses)          
Investments, Owned, Federal Income Tax Note [Line Items]          
Deferred income tax expense (benefit)       300  
Income tax expense       400  
Current income tax       $ 100  
Short-Term Capital Loss Carryforward          
Investments, Owned, Federal Income Tax Note [Line Items]          
Undistributed ordinary income, net         62,800
Long-Term Capital Loss Carryforward          
Investments, Owned, Federal Income Tax Note [Line Items]          
Undistributed ordinary income, net         $ 637,100