CONSOLIDATED STATEMENT 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	$ 92,879	$ 101,299	$ 117,457
Adjustments to reconcile net income to cash flows from operating activities:
Unrealized loss (gain) on derivative instruments	35,789	36,876	(27,392)
Depreciation and amortization	41,643	35,200	33,192
Allowance for equity used during construction	(638)	(2,100)	(2,165)
Allowance for bad debt expense	3,932	4,865	3,307
Deferred income taxes	(5,323)	35,034	68,458
Manufactured gas plant remediation costs	(7,965)	(14,115)	(3,824)
Equity in earnings of affiliates, net of distributions received	6,799	2,791	839
Cost of removal - asset retirement obligations	(1,196)	(826)	(809)
Contributions to postemployment benefit plans	(25,874)	(11,496)	(19,567)
Changes in:
Components of working capital	(95,357)	43,748	(35,297)
Other noncurrent assets	(20,539)	7,081	3,525
Other noncurrent liabilities	26,931	11,744	1,691
Cash flows from operating activities	51,081	250,101	139,415
CASH FLOWS (USED IN) INVESTING ACTIVITIES
Utility plant expenditures	(104,277)	(93,624)	(86,620)
Solar equipment expenditures	(89,726)	(71,989)	(2,641)
Real estate properties and other expenditures	(1,334)	(3,549)	(917)
Cost of removal expenditures	(12,178)	(8,369)	(7,201)
Investments in equity investees	(8,800)	0	(4,300)
Withdrawal from (investment in) restricted cash construction fund	(802)	58	(445)
Proceeds from asset sales	0	2,396	0
Proceeds from available for sale investments	0	0	721
Cash flows (used in) investing activities	(217,117)	(175,077)	(101,403)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES
Proceeds from issuance of common stock	13,834	13,704	6,487
Tax benefit from stock options exercised	780	2,007	669
Proceeds from sale-leaseback transaction	6,522	5,901	4,925
Refinancing of long-term debt	0	97,045	0
Proceeds from long-term debt	100,000	0	0
Payments of long-term debt	(8,025)	(130,091)	(6,749)
Purchases of treasury stock	(8,768)	(10,193)	(29,650)
Payments of common stock dividends	(61,688)	(58,650)	(53,137)
Net proceeds of short-term debt	120,450	11,750	4,200
Cash flows from (used in) financing activities	163,105	(68,527)	(73,255)
Change in cash and cash equivalents	(2,931)	6,497	(35,243)
Cash and cash equivalents at beginning of period	7,440	943	36,186
Cash and cash equivalents at end of period	4,509	7,440	943
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	36,670	(49,473)	(66,189)
Inventories	28,814	40,363	(38,743)
Recovery of gas costs	(11,686)	41,118	(72,688)
Gas purchases payable	(70,277)	22,289	100,290
Prepaid and accrued taxes	23,036	(8,691)	(10,431)
Accounts payable and other	(3,418)	4,469	291
Restricted broker margin accounts	666	(31,813)	35,468
Customers' credit balances and deposits	(65,324)	21,819	18,740
Other current assets	(33,838)	3,667	(2,035)
Components of working capital	(95,357)	43,748	(35,297)
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION
Cash paid for Interest (net of amounts capitalized)	16,670	17,323	14,665
Cash paid for Income taxes	10,053	5,165	24,177
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING ACTIVITIES
Accrued capital expenditures	$ 8,257	$ 9,423	$ 1,575