Investments - Schedule of Investments Excluding Investments in Money Market Funds (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Schedule Of Investments [Line Items]
Cost	$ 3,403,111	$ 3,395,166
Fair Value	3,228,940	3,261,721
1st Lien/Senior Secured Debt
Schedule Of Investments [Line Items]
Cost	3,096,064	3,088,308
Fair Value	3,002,029	3,028,788
1st Lien/Last-Out Unitranche
Schedule Of Investments [Line Items]
Cost	137,070	138,148
Fair Value	130,886	135,156
2nd Lien/Senior Secured Debt
Schedule Of Investments [Line Items]
Cost	51,353	50,613
Fair Value	52,766	47,914
Unsecured Debt
Schedule Of Investments [Line Items]
Cost	30,022	29,603
Fair Value	8,521	8,476
Preferred Stock
Schedule Of Investments [Line Items]
Cost	33,209	33,101
Fair Value	20,124	26,426
Common Stock
Schedule Of Investments [Line Items]
Cost	53,544	53,544
Fair Value	14,153	14,714
Warrants
Schedule Of Investments [Line Items]
Cost	1,849	1,849
Fair Value	$ 461	$ 247