Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 87,898	$ 105,196	$ 90,258
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	52,792	52,546	53,476
Deferred income taxes, net	53,247	50,823	63,654
Pension expense, net of contributions paid	(17,431)	(6,292)	6,698
Provision for uncollectible accounts	6,286	9,137	10,651
Other, net	2,490	(4,526)	10,257
Net change in:
Accounts receivable and accrued utility revenues	5,461	(4,583)	2,847
Inventories	36,929	14,596	77,740
Deferred fuel costs, net of changes in unsettled derivatives	(8,190)	12,842	(18,500)
Accounts payable	(6,718)	9,229	7,424
Storage agreement security deposits	0	0	3,500
Other current assets	(5,063)	(3,817)	(15,511)
Other current liabilities	2,041	(14,401)	(889)
Net cash provided by operating activities	209,742	220,750	291,605
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for property, plant and equipment	(114,090)	(98,856)	(81,595)
Net costs of property, plant and equipment disposals	(4,922)	(3,537)	(3,980)
Decrease (increase) in restricted cash	4,308	390	(4,698)
Net cash used by investing activities	(114,704)	(102,003)	(90,273)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of dividends	(70,615)	(99,490)	(74,008)
Increase (decrease) in bank loans	9,200	(17,000)	(137,000)
Repayments of long-term debt	(40,000)	0	0
Excess tax benefits from equity-based payment arrangements	369	692	471
Net cash used by financing activities	(101,046)	(115,798)	(210,537)
Cash and cash equivalents (decrease) increase	(6,008)	2,949	(9,205)
CASH AND CASH EQUIVALENTS:
End of year	1,259	7,267	4,318
Beginning of year	7,267	4,318	13,523
(Decrease) increase	(6,008)	2,949	(9,205)
Cash paid for:
Interest	29,902	39,151	39,917
Income taxes	$ 6,728	$ 13,856	$ 6,217