EMPLOYEE BENEFIT PLANS, Defined Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension [Member]
Components of net periodic cost
Service cost	$ 1,344,000	$ 1,194,000	$ 4,032,000	$ 3,582,000
Interest cost	2,206,000	2,094,000	6,618,000	6,283,000
Expected return on plan assets	(3,171,000)	(2,873,000)	(9,513,000)	(8,618,000)
Recognized actuarial loss	1,254,000	987,000	3,762,000	2,960,000
Prior service cost amortization	11,000	12,000	33,000	36,000
Recognized net initial obligation	0	0	0	0
Net periodic cost	1,644,000	1,414,000	4,932,000	4,243,000
Pension Plans Excluding Pension Equalization Plan, Defined Benefit [Member]
Components of net periodic cost
Defined Benefit Plan, Contributions by Employer			20,000,000
OPEB [Member]
Components of net periodic cost
Service cost	896,000	836,000	2,688,000	2,508,000
Interest cost	1,283,000	1,211,000	3,849,000	3,634,000
Expected return on plan assets	(687,000)	(618,000)	(2,059,000)	(1,854,000)
Recognized actuarial loss	724,000	653,000	2,172,000	1,959,000
Prior service cost amortization	6,000	19,000	18,000	57,000
Recognized net initial obligation	89,000	89,000	267,000	267,000
Net periodic cost	$ 2,311,000	$ 2,190,000	$ 6,935,000	$ 6,571,000