EMPLOYEE BENEFIT PLANS, ASSUMED HCCTR (Details) - OPEB [Member] - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
HCCTR	6.70%	7.10%	7.30%
Ultimate HCCTR	4.80%	4.80%	4.80%
Year ultimate HCCTR reached	2022	2022	2022
Effect of a 1 percentage point increase in the HCCTR on:
Year-end benefit obligation	$ 26,025	$ 20,965	$ 18,008
Total service and interest cost	2,026	1,885	2,156
Effect of a 1 percentage point decrease in the HCCTR on:
Year-end benefit obligation	(20,427)	(16,932)	(14,629)
Total service and interest costs	$ (1,593)	$ (1,493)	$ (1,675)