ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Changes in foreign currency translation
Beginning accumulated foreign currency translation	$ 1,047	$ 836	$ 1,053	$ 906
Change in cumulative translation adjustment before reclassifications	(181)	22	(187)	(48)
Income taxes	0	0	0	0
Net current period other comprehensive (loss) income	(181)	22	(187)	(48)
Ending accumulated foreign currency translation	866	858	866	858
Changes in retirement plans
Beginning accumulated retirement plans benefit cost	(2,087)	(4,729)	(2,111)	(4,826)
Amortization of net actuarial loss and prior service cost	39	96	63	193
Income taxes	0	0	0	0
Net current period other comprehensive income	39	96	63	193
Ending accumulated retirement plans benefit cost	(2,048)	(4,633)	(2,048)	(4,633)
Accumulated other comprehensive loss, net of taxes	$ (1,182)	$ (3,775)	$ (1,182)	$ (3,775)	$ (1,058)