Acquisitions and Dispositions - Summary of Unaudited Pro Forma Results of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]
Pro forma revenues	$ 1,872,334	$ 1,779,550	$ 1,957,897
Pro forma net loss	$ (116,230)	$ (6,535)	$ (38,024)