RETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Net periodic benefit cost:
Service cost	$ 50	$ 53
Interest cost	93	89
Expected return on plan assets	(161)	(147)
Amortization of prior service cost (credit)	1	1
Amortization of net actuarial loss	3	21
Net periodic benefit (income) cost	(14)	17
Other disclosures
Estimated future Pension Plan contributions	150
SERP
Net periodic benefit cost:
Service cost	9	6
Interest cost	21	15
Amortization of prior service cost (credit)	(1)	(1)
Amortization of net actuarial loss	1	0
Net periodic benefit (income) cost	30	20
Postretirement Medical
Net periodic benefit cost:
Service cost	0	0
Interest cost	25	19
Amortization of prior service cost (credit)	0	0
Amortization of net actuarial loss	13	3
Net periodic benefit (income) cost	$ 38	$ 22