Fair Value of Financial Instruments - Net Change in Unrealized Gains or Losses on Investments for Which Level 3 Inputs were Used in Determining Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	$ 79,859		$ 61,325
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	18,893	$ 13,761
Level 3 | First-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	13,833	$ 13,761
Level 3 | Second-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	(227)
Level 3 | Mezzanine Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	1,804
Level 3 | Equity and Other Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	$ 3,483