v3.26.3
Investments - Investments at Fair Value and Amortized Cost (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Amortized Cost [1],[2] $ 15,107,313 $ 14,127,213
Fair Value 14,814,824 14,286,039
First-lien senior secured debt investments    
Schedule of Investments [Line Items]    
Amortized Cost 11,738,092 10,983,810
Fair Value 11,555,643 10,979,070
Second-lien senior secured debt investments    
Schedule of Investments [Line Items]    
Amortized Cost 608,898 601,494
Fair Value 502,234 568,641
Unsecured debt investments    
Schedule of Investments [Line Items]    
Amortized Cost 474,595 467,464
Fair Value 478,830 477,128
Specialty finance debt investments    
Schedule of Investments [Line Items]    
Amortized Cost 42,563 37,449
Fair Value 42,568 37,452
Preferred equity investments    
Schedule of Investments [Line Items]    
Amortized Cost 1,167,252 1,127,105
Fair Value 990,315 1,072,481
Common equity investments    
Schedule of Investments [Line Items]    
Amortized Cost 542,607 504,733
Fair Value 688,504 722,100
Specialty finance equity investments    
Schedule of Investments [Line Items]    
Amortized Cost 478,684 351,675
Fair Value 504,789 375,812
Joint ventures    
Schedule of Investments [Line Items]    
Amortized Cost 54,622 53,483
Fair Value $ 51,941 $ 53,355
[1] The amortized cost represents the original cost adjusted for the amortization or accretion of premium or discount, as applicable, on debt investments using the effective interest method.
[2] As of September 30, 2026, the net estimated unrealized loss for U.S. federal income tax purposes was $71.3 million based on a tax cost basis of $14.9 billion. As of September 30, 2026, the estimated aggregate gross unrealized loss for U.S. federal income tax purposes was $754.7 million and the estimated aggregate gross unrealized gain for U.S. federal income tax purposes was $683.3 million.