ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Changes in foreign currency translation
Beginning accumulated foreign currency translation	$ 512	$ 1,047	$ 925	$ 1,053
Change in cumulative translation adjustment before reclassifications	130	(181)	(283)	(187)
Income taxes	0	0	0	0
Net current period other comprehensive income (loss)	130	(181)	(283)	(187)
Ending accumulated foreign currency translation	642	866	642	866
Changes in retirement plans
Beginning accumulated retirement plans benefit cost	(1,422)	(2,087)	(1,439)	(2,111)
Amortization of net actuarial loss and prior service cost	16	39	33	63
Income taxes	0	0	0	0
Net current period other comprehensive income	16	39	33	63
Ending accumulated retirement plans benefit cost	(1,406)	(2,048)	(1,406)	(2,048)
Accumulated other comprehensive loss, net of taxes	$ (764)	$ (1,182)	$ (764)	$ (1,182)	$ (514)