Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 49,888	$ 68,303
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	22,474	20,354
Deferred income taxes, net	6,721	4,328
Provision for uncollectible accounts	5,029	3,459
Other, net	11,451	1,161
Net change in:
Accounts receivable and accrued utility revenues	(99,882)	(136,036)
Inventories	1,615	3,592
Deferred fuel and power costs, net of changes in unsettled derivatives	(12,501)	11,572
Accounts payable	42,936	21,655
Other current assets	(8,150)	(6,661)
Other current liabilities	(4,142)	1,172
Net cash provided (used) by operating activities	15,439	(7,101)
CASH FLOWS FROM INVESTING ACTIVITIES
Expenditures for property, plant and equipment	(98,717)	(88,686)
Net costs of property, plant and equipment disposals	(1,691)	(2,382)
Net cash used by investing activities	(100,408)	(91,068)
CASH FLOWS FROM FINANCING ACTIVITIES
Payment of dividends	(5,000)	(15,000)
Issuances of long-term debt, net of issuance costs	0	124,374
Repayments of long-term debt	(2,433)	(20,000)
Other	(779)	0
Increase in short-term borrowings	106,500	11,500
Net cash provided by financing activities	98,288	100,874
CASH AND CASH EQUIVALENTS
Cash, cash equivalents, and restricted cash, period end	24,823	10,954
Cash, cash equivalents, and restricted cash, period beginning	11,504	8,249
Cash, cash equivalents and restricted cash increase	$ 13,319	$ 2,705