EMPLOYEE BENEFIT PLANS (Details) - USD ($)	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Components of net periodic cost
Discretionary contribution	$ 0
Pension
Components of net periodic cost
Service cost	2,035,000	$ 2,087,000
Interest cost	2,623,000	2,443,000
Expected return on plan assets	(4,910,000)	(4,828,000)
Recognized actuarial loss	1,884,000	2,207,000
Prior service cost amortization	27,000	27,000
Net periodic benefit cost	1,659,000	1,936,000
OPEB
Components of net periodic cost
Service cost	1,152,000	1,095,000
Interest cost	1,591,000	1,386,000
Expected return on plan assets	(1,338,000)	(1,192,000)
Recognized actuarial loss	1,165,000	1,093,000
Prior service cost amortization	(91,000)	(91,000)
Net periodic benefit cost	$ 2,479,000	$ 2,291,000