Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 125,735	$ 128,286
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	46,982	43,985
Deferred income taxes, net	(10,417)	18,747
Provision for uncollectible accounts	10,997	11,657
Other, net	526	(2,809)
Net change in:
Accounts receivable and accrued utility revenues	(27,817)	(44,530)
Inventories	61,843	30,911
Deferred fuel and power costs, net of changes in unsettled derivatives	59,397	(17,611)
Accounts payable	(14,884)	4,070
Other current assets	631	4,690
Other current liabilities	47,939	27,947
Net cash provided by operating activities	300,932	205,343
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for property, plant and equipment	(141,884)	(104,117)
Net costs of property, plant and equipment disposals	(6,358)	(5,222)
(Increase) decrease in restricted cash	(91)	2,072
Net cash used by investing activities	(148,333)	(107,267)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of dividends	(45,600)	(57,549)
Issuances of long-term debt	0	175,000
Repayments of long-term debt	(20,000)	(175,000)
Decrease in short-term borrowings	(83,600)	(17,500)
Other	722	746
Net cash used by financing activities	(148,478)	(74,303)
Cash and cash equivalents increase	4,121	23,773
CASH AND CASH EQUIVALENTS:
End of period	16,522	28,480
Beginning of period	$ 12,401	$ 4,707