EMPLOYEE BENEFIT PLANS, AMOUNTS EXPECTED TO BE RECOGNIZED IN NET PERIODIC BENEFIT COST (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2016 USD ($)
Pension
Regulatory Assets
Net actuarial loss	$ 6,799
Prior service cost (credit)	108
Total	6,907
Accumulated Other Comprehensive Income (Loss)
Net actuarial loss	2,028
Prior service cost (credit)	3
Total	2,031
OPEB
Regulatory Assets
Net actuarial loss	4,210
Prior service cost (credit)	(311)
Total	3,899
Accumulated Other Comprehensive Income (Loss)
Net actuarial loss	160
Prior service cost (credit)	(54)
Total	$ 106