DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Part 1 (Details) (USD $)	6 Months Ended
	Mar. 31, 2013 MMBTU gal	Sep. 30, 2012	Mar. 31, 2012
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Maximum percentage of normal volumes hedged	70.00%
Maximum number of months normal volumes can be hedged (in months)	36-month
Derivative [Line Items]
Gasoline futures contracts notional amount (in gallons)	500,000
Average price of gasoline futures contracts (dollars per gallon)	$ 2.30
Contract volumes of NYMEX natural gas option used to mitigate price risk (in MMBtu)	14,200,000
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	300,000
Derivative instrument assets reconciliation [Abstract]
Fair value of asset derivatives presented above	11,184,000	7,682,000	790,000
Fair value of cash margin receivables offset with derivatives	0	1,964,000	35,647,000
Netting of assets and liabilities with the same counterparty	(7,879,000)	(9,646,000)	(36,437,000)
Derivative Assets	3,305,000	0	0
Derivative Instrument Assets, per Balance Sheets: [Abstract]
Fair value of liability derivatives presented above	339,000	9,563,000	36,437,000
Fair value of cash margin payables offset with derivatives	7,540,000	83,000	0
Netting of assets and liabilities with the same counterparty	(7,879,000)	(9,646,000)	(36,437,000)
Derivative instrument liabilities, per Balance Sheets	0	0	0
Cash margin receivables not offset with derivatives		8,000,000	8,200,000
Fiscal 2013 [Member] | Open Long Futures Positions [Member]
Derivative [Line Items]
MMBtu	7,580,000
Avg. Price Per MMBtu	3.40
Fiscal 2014 [Member] | Open Long Futures Positions [Member]
Derivative [Line Items]
MMBtu	4,870,000
Avg. Price Per MMBtu	$ 3.97