Fair Value of Financial Instruments - Fair Value of Level 3 Investments at Fair Value Significant Unobservable Inputs Used in Valuations (Details) - Level 3 $ in Thousands	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair Value	$ 7,847,447	$ 7,099,575
Income Approach | First-lien Debt Investments | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair Value	$ 7,398,928	$ 6,728,411
Income Approach | First-lien Debt Investments | Discount Rate | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.066	0.077
Income Approach | First-lien Debt Investments | Discount Rate | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.175	0.171
Income Approach | First-lien Debt Investments | Discount Rate | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.098	0.106
Income Approach | Second-lien Debt Investments | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair Value	$ 37,160	$ 93,469
Income Approach | Second-lien Debt Investments | Discount Rate | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.125	0.147
Income Approach | Second-lien Debt Investments | Discount Rate | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.141	0.181
Income Approach | Second-lien Debt Investments | Discount Rate | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.136	0.178
Income Approach | Mezzanine Debt Investments | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair Value	$ 222,366	$ 123,184
Income Approach | Mezzanine Debt Investments | Discount Rate | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.108	0.122
Income Approach | Mezzanine Debt Investments | Discount Rate | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.108	0.122
Income Approach | Mezzanine Debt Investments | Discount Rate | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.108	0.122
Market Multiple | Equity and Other Investments | Comparable Multiple
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair Value	$ 188,993	$ 154,511
Market Multiple | Equity and Other Investments | Comparable Multiple | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.028	0.048
Market Multiple | Equity and Other Investments | Comparable Multiple | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.25	0.20
Market Multiple | Equity and Other Investments | Comparable Multiple | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Investment measurement input	0.135	0.11