Quarterly report [Sections 13 or 15(d)]

Investments - Schedule of Realized Gains and Losses and Changes in Unrealized Appreciation and Depreciation on Control and Affiliate investments (Details)

v3.25.1
Investments - Schedule of Realized Gains and Losses and Changes in Unrealized Appreciation and Depreciation on Control and Affiliate investments (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Dec. 31, 2023
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) $ 3,924,450   $ 3,659,978  
Interest & Dividend Income 115,572 $ 115,779    
Fee Income 3,939 5,774    
Net Change in Unrealized Appreciation (Depreciation) (25,565) 3,634    
Control investments        
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) 115,734 112,215 $ 113,179 $ 115,004
Interest & Dividend Income 3,637 2,957    
Fee Income 39 36    
Net Change in Unrealized Appreciation (Depreciation) 1,977 (2,829)    
Realized Gain (Loss) 0 0    
Control investments | Coronado Aesthetics, LLC        
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) 47 283    
Interest & Dividend Income 0 0    
Fee Income 0 0    
Net Change in Unrealized Appreciation (Depreciation) (22) 21    
Realized Gain (Loss) 0 0    
Control investments | Gibraltar Business Capital, LLC        
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) 58,900 57,931    
Interest & Dividend Income 1,567 1,033    
Fee Income 39 36    
Net Change in Unrealized Appreciation (Depreciation) (941) (4,621)    
Realized Gain (Loss) 0 0    
Control investments | Hercules Adviser LLC        
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) 45,017 41,884    
Interest & Dividend Income 1,900 1,752    
Fee Income 0 0    
Net Change in Unrealized Appreciation (Depreciation) 2,827 1,171    
Realized Gain (Loss) 0 0    
Control investments | Tectura Corporation        
Schedule Of Investments [Line Items]        
Fair value of investments (in millions) 11,770 12,117    
Interest & Dividend Income 170 172    
Fee Income 0 0    
Net Change in Unrealized Appreciation (Depreciation) 113 600    
Realized Gain (Loss) $ 0 $ 0