ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Foreign currency translation:
Balance at beginning of period	$ 545	$ 691
Change in cumulative translation adjustment before reclassifications	(283)	(146)
Foreign currency translation adjustments, taxes	0	0
Net current period other comprehensive loss	(283)	(146)
Balance at end of the period	262	545
Retirement plans:
Balance at beginning of period	(1,980)	(3,608)
Amortization of net actuarial loss and prior service cost	101	120
Net actuarial gains arising during the period	1,108	1,508
Gain on termination of post-retirement medical plan	541	0
Amortization of accumulated other comprehensive loss into net periodic benefit costs, taxes	0	0
Net current period other comprehensive income	1,750	1,628
Balance at end of the period	(230)	(1,980)
Accumulated other comprehensive income (loss), net	$ 32	$ (1,435)