Portfolio Investments - Schedule of Composition of Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025
Schedule of Investments [Line Items]
Fair Value	$ 7,404,628	$ 6,867,378
% of Debt Investments	100.00%	100.00%
Floating rate
Schedule of Investments [Line Items]
Fair Value	$ 6,930,878	$ 6,413,837
% of Debt Investments	93.60%	93.40%
Fixed rate
Schedule of Investments [Line Items]
Fair Value	$ 473,750	$ 453,541
% of Debt Investments	6.40%	6.60%