Fair Value of Financial Instruments - Fair Value Measurements of Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other investments	$ 155,600	$ 167,685
Structured credit investments	55,842	51,426
Total investments at fair value	3,283,065	2,787,925
Interest rate swaps	(31,840)	(55,314)
Total	3,251,225	2,732,611
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other investments	5,180	7,498
Total investments at fair value	5,180	7,498
Total	5,180	7,498
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other investments	10,089	13,128
Structured credit investments	55,842	51,426
Total investments at fair value	68,928	86,489
Interest rate swaps	(31,840)	(55,314)
Total	37,088	31,175
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity and other investments	140,331	147,059
Total investments at fair value	3,208,957	2,693,938
Total	3,208,957	2,693,938
First-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	2,996,177	2,517,894
First-lien Debt Investments | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	2,391	21,935
First-lien Debt Investments | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	2,993,786	2,495,959
Second-lien Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	35,975	40,762
Second-lien Debt Investments | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	35,975	40,762
Mezzanine Debt Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	39,471	10,158
Mezzanine Debt Investments | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	606
Mezzanine Debt Investments | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments	$ 38,865	$ 10,158