CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 233,436	$ 132,065	$ 131,672
Adjustments to reconcile net income to cash flows from operating activities
Unrealized loss (gain) on derivative instruments	26,770	(11,241)	46,883
Gain on sale of available for sale securities	(5,332)	(7,287)	0
Gain on sale of businesses	(4,663)	0	0
Depreciation and amortization	85,701	81,841	72,748
Amortization of acquired wholesale energy contracts	18,222	762	0
Allowance for equity used during construction	(5,531)	(3,867)	(4,375)
Allowance for doubtful accounts	2,579	2,023	1,616
Deferred income taxes	15,590	41,442	27,721
Deferred income tax benefit due to tax legislation	(75,736)	0	0
Manufactured gas plant remediation costs	(16,171)	(10,934)	(8,106)
Equity in earnings, net of distributions received from equity investees	(1,725)	(462)	4,534
Cost of removal - asset retirement obligations	(298)	(484)	(403)
Contributions to postemployment benefit plans	(6,359)	(6,077)	(33,359)
Tax benefit of delivered shares from stock based compensation	2,950	1,285	1,755
Changes in:
Components of working capital	97,004	17,081	(123,325)
Other noncurrent assets	17,860	13,978	3,933
Other noncurrent liabilities	13,989	(2,079)	21,336
Cash flows from operating activities	398,286	248,046	142,630
Expenditures for:
Utility plant	(206,880)	(144,106)	(176,067)
Solar and wind equipment	(123,421)	(149,400)	(149,063)
Midstream and other	(6,644)	(2,434)	(1,896)
Cost of removal	(47,643)	(32,143)	(29,066)
Acquisition of retail and wholesale energy contracts	0	(55,661)	0
Investments in equity investees	(16,151)	(27,070)	(11,176)
Distributions from equity investees in excess of equity in earnings	3,117	2,749	2,351
Acquisition of retail and wholesale energy contracts	(10,000)	0	0
(Deposits to) withdrawal from restricted cash construction fund	(9)	1,322	979
Proceeds from sale of property, net of closing costs	0	9,443	748
Proceeds from sale of businesses, net of closing costs	27,916	0	0
Proceeds from sale of available for sale securities, net	6,616	6,639	0
Cash flows used in investing activities	(373,099)	(390,661)	(363,190)
CASH FLOWS (USED IN) FROM FINANCING ACTIVITIES
Proceeds from long-term debt	225,000	100,000	275,000
Payments of long-term debt	(165,486)	(97,854)	(13,289)
(Payments of) proceeds from short-term debt, net	(114,050)	144,300	55,350
Proceeds from sale-leaseback transaction - solar	71,538	32,901	0
Proceeds from sale-leaseback transaction - gas meters	7,820	9,587	7,107
Payments of common stock dividends	(95,835)	(87,988)	(82,445)
Proceeds from waiver discount issuance of common stock	41,677	0	0
Proceeds from issuance of common stock	17,136	17,492	16,010
Purchases of treasury stock	0	(6,355)	(1,008)
Tax withholding payments related to net settled stock compensation	(13,755)	(4,788)	(3,547)
Cash flows (used in) from financing activities	(25,955)	107,295	253,178
Change in cash and cash equivalents	(768)	(35,320)	32,618
Cash and cash equivalents at beginning of period	2,226	37,546	4,928
Cash and cash equivalents at end of period	1,458	2,226	37,546
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	(7,524)	(56,974)	11,303
Inventories	15,464	3,022	(45,986)
Recovery of gas costs	30,439	(90)	(39,642)
Gas purchases payable	51,187	20,663	(11,963)
Gas purchases payable - related parties	(1)	2	(411)
Prepaid and accrued taxes	1,254	10,366	2,385
Accounts payable and other	40,422	13,086	(15,656)
Restricted broker margin accounts	(30,974)	22,570	(38,752)
Customers’ credit balances and deposits	368	(5,877)	12,044
Other current assets	(3,631)	10,313	3,353
Components of working capital	97,004	17,081	(123,325)
Cash paid (received) for:
Interest (net of amounts capitalized)	44,821	44,362	31,996
Income taxes	5,577	(6,877)	(3,516)
Accrued capital expenditures	30,559	21,769	48,881
Inception gain on natural gas swap contract recognized as non-cash proceeds from sale of business	$ 14,579	$ 0	$ 0