Investments - Schedule of Investments Excluding Investments in Money Market Funds (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Schedule Of Investments [Line Items]
Cost	$ 3,395,166	$ 3,673,582
Fair Value	3,261,721	3,475,258
1st Lien/Senior Secured Debt
Schedule Of Investments [Line Items]
Cost	3,088,308	3,301,746
Fair Value	3,028,788	3,179,820
1st Lien/Last-Out Unitranche
Schedule Of Investments [Line Items]
Cost	138,148	168,709
Fair Value	135,156	165,905
2nd Lien/Senior Secured Debt
Schedule Of Investments [Line Items]
Cost	50,613	57,161
Fair Value	47,914	46,786
Unsecured Debt
Schedule Of Investments [Line Items]
Cost	29,603	39,124
Fair Value	8,476	16,790
Preferred Stock
Schedule Of Investments [Line Items]
Cost	33,101	35,513
Fair Value	26,426	31,246
Common Stock
Schedule Of Investments [Line Items]
Cost	53,544	69,480
Fair Value	14,714	34,290
Warrants
Schedule Of Investments [Line Items]
Cost	1,849	1,849
Fair Value	$ 247	$ 421