Quarterly report [Sections 13 or 15(d)]

Fair Value of Financial Instruments - Schedule of Quantitative Information of Fair Value Measurements (Details)

v3.25.2
Fair Value of Financial Instruments - Schedule of Quantitative Information of Fair Value Measurements (Details) - Significant Unobservable Inputs (Level 3)
$ in Thousands
Jun. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Debt investments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 3,978,695 $ 3,494,601
Debt investments | Debt Investments originated within 6 months    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments 860,350 242,833
Debt investments | Debt Investments Maturing in Less than One Year    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments 128,323 36,185
Debt investments | Debt Investments in Wholly-Owned Subsidiaries    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments 37,388 48,212
Debt investments | Imminent Payoffs    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments 122,740 4,141
Escrow and Other Investment Receivables | Expected Proceeds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments 211  
Accounts payable and accrued liabilities | Liquidation    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ (349) $ (1,012)
Accounts payable and accrued liabilities | Liquidation | Minimum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2000 0.2000
Accounts payable and accrued liabilities | Liquidation | Maximum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.5000 0.5000
Accounts payable and accrued liabilities | Liquidation | Weighted Average | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.4385 0.3844
Total Level Three Debt Investments and Other Investment Receivables (Payables)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 3,978,557 $ 3,493,589
Equity Investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 51,729 $ 45,420
Equity Investments | Market Comparable Companies | Minimum | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.3 0.4
Equity Investments | Market Comparable Companies | Minimum | Tangible Book Value Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 1.5 1.7
Equity Investments | Market Comparable Companies | Minimum | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1313 0.1764
Equity Investments | Market Comparable Companies | Maximum | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 17.6 16.8
Equity Investments | Market Comparable Companies | Maximum | Tangible Book Value Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 1.5 1.7
Equity Investments | Market Comparable Companies | Maximum | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.9228 0.9280
Equity Investments | Market Comparable Companies | Weighted Average | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 7.9 9.1
Equity Investments | Market Comparable Companies | Weighted Average | Tangible Book Value Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 1.5 1.7
Equity Investments | Market Comparable Companies | Weighted Average | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2985 0.3612
Equity Investments | Market Adjusted OPM Backsolve    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 9,538 $ 12,374
Equity Investments | Market Adjusted OPM Backsolve | Minimum | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.8988) (0.9657)
Equity Investments | Market Adjusted OPM Backsolve | Maximum | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1022 0.2476
Equity Investments | Market Adjusted OPM Backsolve | Weighted Average | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.2016) (0.1757)
Equity Investments | Discounted Cash Flow    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 54,164 $ 34,677
Equity Investments | Discounted Cash Flow | Minimum | Discount Rate    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1191 0.1217
Equity Investments | Discounted Cash Flow | Maximum | Discount Rate    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.3453 0.3334
Equity Investments | Discounted Cash Flow | Weighted Average | Discount Rate    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2994 0.3021
Equity Investments | Other    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 3,394 $ 5,924
Warrants | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 22,159 $ 18,302
Warrants | Market Comparable Companies | Minimum | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.5 0.8
Warrants | Market Comparable Companies | Minimum | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0672 0.1472
Warrants | Market Comparable Companies | Maximum | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 15.1 14.1
Warrants | Market Comparable Companies | Maximum | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.3284 0.3435
Warrants | Market Comparable Companies | Weighted Average | Revenue Multiple    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 4.7 4.5
Warrants | Market Comparable Companies | Weighted Average | Discount for Lack of Marketability    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2494 0.2676
Warrants | Market Adjusted OPM Backsolve    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 2,320 $ 3,521
Warrants | Market Adjusted OPM Backsolve | Minimum | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.6324) (0.5636)
Warrants | Market Adjusted OPM Backsolve | Maximum | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.0156) 0.2476
Warrants | Market Adjusted OPM Backsolve | Weighted Average | Market Equity Adjustment    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.1782) 0.0133
Equity and Warrant Investments    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 143,304 $ 120,218
Pharmaceuticals | Debt investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 700,903 $ 947,065
Pharmaceuticals | Debt investments | Market Comparable Companies | Minimum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0883 0.0842
Pharmaceuticals | Debt investments | Market Comparable Companies | Minimum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.0250) (0.0250)
Pharmaceuticals | Debt investments | Market Comparable Companies | Maximum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1639 0.1619
Pharmaceuticals | Debt investments | Market Comparable Companies | Maximum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0300 0.0300
Pharmaceuticals | Debt investments | Market Comparable Companies | Weighted Average | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1334 0.1203
Pharmaceuticals | Debt investments | Market Comparable Companies | Weighted Average | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0057 0.0013
Pharmaceuticals | Debt investments | Liquidation    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments   $ 55,344
Pharmaceuticals | Debt investments | Liquidation | Minimum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input   0.2000
Pharmaceuticals | Debt investments | Liquidation | Maximum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input   0.8000
Pharmaceuticals | Debt investments | Liquidation | Weighted Average | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input   0.7553
Technology | Debt investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 1,309,186 $ 1,365,943
Technology | Debt investments | Market Comparable Companies | Minimum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0968 0.1021
Technology | Debt investments | Market Comparable Companies | Minimum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.0150) (0.0075)
Technology | Debt investments | Market Comparable Companies | Maximum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2155 0.2058
Technology | Debt investments | Market Comparable Companies | Maximum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0550 0.0450
Technology | Debt investments | Market Comparable Companies | Weighted Average | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1314 0.1310
Technology | Debt investments | Market Comparable Companies | Weighted Average | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0012 0.0020
Technology | Debt investments | Convertible Note Analysis    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 28,869 $ 26,869
Technology | Debt investments | Convertible Note Analysis | Minimum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0100 0.0100
Technology | Debt investments | Convertible Note Analysis | Maximum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.7000 0.7000
Technology | Debt investments | Convertible Note Analysis | Weighted Average | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.5095 0.5066
Technology | Debt investments | Liquidation    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 43,706 $ 51,004
Technology | Debt investments | Liquidation | Minimum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.2000 0.2200
Technology | Debt investments | Liquidation | Maximum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.8000 0.7800
Technology | Debt investments | Liquidation | Weighted Average | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.7473 0.6634
Medical Devices | Debt investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 74,663 $ 59,645
Medical Devices | Debt investments | Market Comparable Companies | Minimum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1198 0.1179
Medical Devices | Debt investments | Market Comparable Companies | Minimum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0000 0.0000
Medical Devices | Debt investments | Market Comparable Companies | Maximum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1326 0.1275
Medical Devices | Debt investments | Market Comparable Companies | Maximum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0050 0.0050
Medical Devices | Debt investments | Market Comparable Companies | Weighted Average | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1259 0.1224
Medical Devices | Debt investments | Market Comparable Companies | Weighted Average | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0021 0.0026
Lower Middle Market | Debt investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 627,782 $ 636,258
Lower Middle Market | Debt investments | Market Comparable Companies | Minimum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1012 0.1027
Lower Middle Market | Debt investments | Market Comparable Companies | Minimum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input (0.0025) (0.0025)
Lower Middle Market | Debt investments | Market Comparable Companies | Maximum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1815 0.2100
Lower Middle Market | Debt investments | Market Comparable Companies | Maximum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0300 0.0500
Lower Middle Market | Debt investments | Market Comparable Companies | Weighted Average | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1407 0.1412
Lower Middle Market | Debt investments | Market Comparable Companies | Weighted Average | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0059 0.0107
Lower Middle Market | Debt investments | Liquidation    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 24,603  
Lower Middle Market | Debt investments | Liquidation | Minimum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.4000  
Lower Middle Market | Debt investments | Liquidation | Maximum | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.6000  
Lower Middle Market | Debt investments | Liquidation | Weighted Average | Probability weighting of alternative outcomes    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.6000  
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investments $ 20,182 $ 21,102
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Minimum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1545 0.1241
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Minimum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0050 0.0025
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Maximum | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1545 0.1544
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Maximum | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0050 0.0350
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Weighted Average | Hypothetical Market Yield    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.1545 0.1525
Sustainable and Renewable Technology | Debt investments | Market Comparable Companies | Weighted Average | Premium/(Discount)    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]    
Investment company, investment owned, measurement input 0.0050 0.0045