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		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)			$ 27,899		$ 13,199
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	$ 10,318	$ (13,265)	25,103	$ (47,135)
Level 3 | First-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	11,306	(8,880)	40,214	(39,664)
Level 3 | Second-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	1	(344)	(6,140)	(1,629)
Level 3 | Mezzanine Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	411	(494)	976	(6,639)
Level 3 | Equity and Other Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Net Unrealized Gain (Loss)	$ (1,400)	$ (3,547)	$ (9,947)	$ 797