Change in Net Assets from Operations Per Common Share - Summary of Information Sets Forth for Computation of Basic and Diluted Per Share Net Increase in Net Assets Resulting from Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Income (Loss)	$ 32,726	$ 48,851	$ (33,807)
Denominator for basic weighted average shares	65,296,094	65,246,011	65,224,500
Denominator for diluted weighted average shares	65,296,094	65,246,011	65,224,500
Basic and diluted net increase (decrease) in net assets per share resulting from operations	$ 0.5	$ 0.75	$ (0.52)