CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (15,175)	$ 472,872	$ 689,899
Other comprehensive (loss) income, net of tax:
Change in foreign currency translation adjustment	1,112	14,453	10,212
Change in unrecognized income related to pension benefit plans	(6)	393	5,994
Total other comprehensive income	1,106	14,846	16,206
Comprehensive (loss) income	$ (14,069)	$ 487,718	$ 706,105