CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
OPERATING REVENUES
Utility		$ 695,637	$ 594,346	$ 781,970
Nonutility		1,572,980	1,286,559	1,952,017
Total operating revenues		2,268,617	1,880,905	2,733,987
Gas purchases:
Utility		258,687	205,034	304,953
Nonutility		1,436,740	1,139,301	1,767,841
Related parties		8,340	8,351	12,851
Operation and maintenance		226,356	208,421	209,453
Regulatory rider expenses		40,243	39,300	75,779
Depreciation and amortization		81,841	72,748	61,399
Energy and other taxes		49,366	40,215	53,260
Total operating expenses		2,101,573	1,713,370	2,485,536
OPERATING INCOME		167,044	167,535	248,451
Other income, net		14,437	9,196	6,545
Interest expense, net of capitalized interest		44,886	31,044	27,721
INCOME BEFORE INCOME TAXES AND EQUITY IN EARNINGS OF AFFILIATES		136,595	145,687	227,275
Income tax provision		18,343	23,530	59,724
Equity in earnings of affiliates		13,813	9,515	13,409
NET INCOME		$ 132,065	$ 131,672	$ 180,960
EARNINGS PER COMMON SHARE
Basic (in dollars per share)		$ 1.53	$ 1.53	$ 2.12
Diluted (in dollars per share)	[1]	1.52	1.52	2.10
DIVIDENDS DECLARED PER COMMON SHARE (in usd per share)		$ 1.0375	$ 0.975	$ 0.915
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)		86,321	85,884	85,186
Diluted (in shares)		87,144	86,731	86,265

[1] There were no anti-dilutive shares excluded from the calculation of diluted earnings per share for fiscal 2017, 2016 and 2015.