EMPLOYEE BENEFIT PLANS - COMPONENTS OF NET PERIODIC COST (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income, net
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 4,976	$ 5,402	$ 8,291
Interest cost	16,240	15,174	9,632
Expected return on plan assets	(20,346)	(19,972)	(21,275)
Recognized actuarial loss	117	300	8,745
Prior service cost (credit) amortization	61	103	101
Net periodic benefit cost recognized as expense	1,048	1,007	5,494
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,406	2,471	4,305
Interest cost	8,327	9,146	6,355
Expected return on plan assets	(7,920)	(6,721)	(7,575)
Recognized actuarial loss	4,262	0	5,684
Prior service cost (credit) amortization	(10,013)	0	(144)
Net periodic benefit cost recognized as expense	$ (3,938)	$ 4,896	$ 8,625