EMPLOYEE BENEFIT PLANS - COMPONENTS OF NET PERIODIC COST (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1,350	$ 2,073
Interest cost	3,794	2,408
Expected return on plan assets	(4,993)	(5,319)
Recognized actuarial loss	75	2,186
Prior service cost (credit) amortization	25	25
Net periodic benefit cost	251	1,373
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	618	1,076
Interest cost	2,286	1,589
Expected return on plan assets	(1,680)	(1,894)
Recognized actuarial loss	0	1,421
Prior service cost (credit) amortization	0	(36)
Net periodic benefit cost	$ 1,224	$ 2,156