Fair Value Measurement - Summary of Assets Categorized Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	$ 3,440,114	$ 3,414,329
Debt investments, Fair Value	3,440,613
Foreign Currency Forward Contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unrealized appreciation (depreciation) on foreign currency forward contracts	(581)	(726)
1st Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	3,162,664	3,107,469
1st Lien/Last-Out Unitranche
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	158,514	144,743
2nd Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	33,636	66,562
Unsecured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	20,550	27,314
Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	38,002	37,296
Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	26,501	30,701
Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	247	244
Affiliated Money Market Fund
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	499
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value		190
Debt investments, Fair Value	697
Level 1 | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	198	190
Level 1 | Affiliated Money Market Fund
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	499
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	62,848	70,504
Level 2 | Foreign Currency Forward Contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unrealized appreciation (depreciation) on foreign currency forward contracts	(581)	(726)
Level 2 | 1st Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	62,848	70,504
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	3,377,068	3,343,635
Level 3 | 1st Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	3,099,816	3,036,965
Level 3 | 1st Lien/Last-Out Unitranche
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	158,514	144,743
Level 3 | 2nd Lien/Senior Secured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	33,636	66,562
Level 3 | Unsecured Debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	20,550	27,314
Level 3 | Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	38,002	37,296
Level 3 | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	26,303	30,511
Level 3 | Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt investments, Fair Value	$ 247	$ 244