RETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Pension Plan
Net periodic benefit cost:
Service cost	$ 55	$ 72	$ 108	$ 144
Interest cost	89	87	178	174
Expected return on plan assets	(148)	(141)	(296)	(282)
Amortization of prior service cost (credit)	2	1	3	2
Amortization of net actuarial loss	27	41	49	82
Net periodic benefit cost	25	60	42	120
Other disclosures
Contribution by the entity to the Pension Plan			200
Estimated future employer contributions	300		300
SERP
Net periodic benefit cost:
Service cost	13	15	20	31
Interest cost	23	20	38	41
Amortization of prior service cost (credit)	(1)	(1)	(3)	(2)
Amortization of net actuarial loss	7	8	7	17
Net periodic benefit cost	42	42	62	87
Postretirement Medical
Net periodic benefit cost:
Service cost	0	0	0	0
Interest cost	19	22	38	44
Amortization of prior service cost (credit)	0	0	0	0
Amortization of net actuarial loss	3	47	6	94
Net periodic benefit cost	$ 22	$ 69	$ 44	$ 138