v3.26.3
Fair Value of Financial Instruments - Schedule of Fair Value Hierarchy of Investments (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Cash (including foreign cash) $ 220,796 $ 282,924
Fair Value 14,814,824 14,286,039
First-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 11,555,643 10,979,070
Second-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 502,234 568,641
Unsecured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 478,830 477,128
Specialty finance debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 42,568 37,452
Preferred equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 990,315 1,072,481
Common equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 688,504 722,100
Specialty finance equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 504,789 375,812
Interest Rate Swaps    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Derivative assets 6,687 26,732
Cash collateral received 0 0
Derivative liabilities 54,979 1,941
Cash collateral posted 21,690 0
Level 1    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Cash (including foreign cash) 220,796 282,924
Fair Value 125,369 706
Level 1 | First-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Second-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Unsecured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Specialty finance debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Preferred equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Common equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 125,369 706
Level 1 | Specialty finance equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 1 | Interest Rate Swaps    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Derivative assets 0 0
Cash collateral received 0 0
Derivative liabilities 0 0
Cash collateral posted 21,690 0
Level 2    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Cash (including foreign cash) 0 0
Fair Value 415,695 481,386
Level 2 | First-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 274,172 318,098
Level 2 | Second-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 111,282 125,924
Level 2 | Unsecured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 2 | Specialty finance debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 2 | Preferred equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 2 | Common equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 30,241 37,364
Level 2 | Specialty finance equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 0 0
Level 2 | Interest Rate Swaps    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Derivative assets 6,687 26,732
Cash collateral received 0 0
Derivative liabilities 54,979 1,941
Cash collateral posted 0 0
Level 3    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Cash (including foreign cash) 0 0
Fair Value 13,845,101 13,590,644
Level 3 | First-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 11,281,471 10,660,972
Level 3 | Second-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 390,952 442,717
Level 3 | Unsecured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 478,830 477,128
Level 3 | Specialty finance debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 42,568 37,452
Level 3 | Preferred equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 990,315 1,072,481
Level 3 | Common equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 490,196 684,030
Level 3 | Specialty finance equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 170,769 215,864
Level 3 | Interest Rate Swaps    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Derivative assets 0 0
Cash collateral received 0 0
Derivative liabilities 0 0
Cash collateral posted 0 0
Levels 1, Level 2, and Level 3    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 14,386,165 14,072,736
Levels 1, Level 2, and Level 3 | First-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 11,555,643 10,979,070
Levels 1, Level 2, and Level 3 | Second-lien senior secured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 502,234 568,641
Levels 1, Level 2, and Level 3 | Unsecured debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 478,830 477,128
Levels 1, Level 2, and Level 3 | Specialty finance debt investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 42,568 37,452
Levels 1, Level 2, and Level 3 | Preferred equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 990,315 1,072,481
Levels 1, Level 2, and Level 3 | Common equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 645,806 722,100
Levels 1, Level 2, and Level 3 | Specialty finance equity investments    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value 170,769 215,864
Investments measured at NAV    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair Value $ 428,659 $ 213,303