DEFINED BENEFIT PLAN - Net periodic benefit costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Components of net periodic (benefit) expense:
Interest cost	$ 187	$ 207	$ 551	$ 344
Expected return on assets	(203)	(352)	(600)	(681)
Amortization of prior (gain) loss	(39)	177	(114)	454
Net periodic (benefit) expense	$ (55)	$ 32	$ (163)	$ 117
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	General and Administrative Expense	General and Administrative Expense	General and Administrative Expense	General and Administrative Expense