CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
OPERATING REVENUES
Utility	$ 295,546	$ 242,536	$ 481,102	$ 394,142
Nonutility	438,000	331,657	793,472	624,309
Total operating revenues	733,546	574,193	1,274,574	1,018,451
OPERATING EXPENSES
Gas Purchases - Utility	112,445	82,374	173,765	129,039
Gas Purchases - Nonutility	367,328	287,883	705,260	541,971
Gas Purchases - Related parties	2,072	2,077	4,183	4,151
Operation and maintenance	52,342	53,125	104,570	99,358
Regulatory rider expenses	19,893	21,215	32,494	30,843
Depreciation and amortization	20,328	17,744	39,588	34,226
Energy and other taxes	19,485	15,842	33,586	25,479
Total operating expenses	593,893	480,260	1,093,446	865,067
OPERATING INCOME	139,653	93,933	181,128	153,384
Other income, net	5,338	2,202	9,114	4,126
Interest expense, net of capitalized interest	11,436	7,369	22,051	14,146
INCOME BEFORE INCOME TAXES AND EQUITY IN EARNINGS OF AFFILIATES	133,555	88,766	168,191	143,364
Income tax provision	23,932	17,815	25,950	24,537
Equity in earnings of affiliates	5,079	2,402	7,390	4,808
NET INCOME	$ 114,702	$ 73,353	$ 149,631	$ 123,635
EARNINGS PER COMMON SHARE
Basic (usd per share)	$ 1.33	$ 0.85	$ 1.74	$ 1.44
Diluted (usd per share)	1.32	0.84	1.72	1.42
DIVIDENDS DECLARED PER COMMON SHARE (usd per share)	$ 0.255	$ 0.24	$ 0.51	$ 0.48
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)	86,275	85,834	86,182	85,754
Diluted (in shares)	87,101	86,858	86,993	86,778