CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Consolidated net loss	$ (104,902)	$ (337,262)
Foreign currency translation	4,940	(8,115)
Cumulative currency translation realized through sale of subsidiary	762	0
Defined benefit plans:
Actuarial (loss) gains, net of tax	(28)	2,725
Other	(219)	0
Foreign currency translation	375	(110)
Other comprehensive income (loss), net of tax	5,830	(5,500)
Consolidated comprehensive loss	(99,072)	(342,762)
Less: Comprehensive income (loss) attributable to non-controlling interests	238	(244)
Comprehensive loss attributable to common stockholders	$ (99,310)	$ (342,518)