CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2015		Mar. 31, 2014
OPERATING REVENUES
Utility	$ 374,703		$ 394,528		$ 583,430		$ 627,997
Nonutility	638,387		1,185,041		1,253,784		1,829,977
Total operating revenues	1,013,090		1,579,569		1,837,214		2,457,974
OPERATING EXPENSES
Gas Purchases - Utility	129,281		146,449		213,544		255,937
Gas Purchases - Nonutility	662,573		1,046,328		1,135,544		1,708,272
Gas Purchases - Related parties	3,124		3,039		6,388		6,339
Operation and maintenance	52,778		61,273		97,537		103,296
Regulatory rider expenses	42,692		38,211		64,155		58,043
Depreciation and amortization	15,204		12,828		29,590		25,394
Energy and other taxes	24,632		24,429		38,953		41,457
Total operating expenses	930,284		1,332,557		1,585,711		2,198,738
OPERATING INCOME	82,806		247,012		251,503		259,236
Other income, net	1,137		712		1,027		1,839
Interest expense, net of capitalized interest	6,483		6,306		13,678		12,601
INCOME BEFORE INCOME TAXES AND EQUITY IN EARNINGS OF AFFILIATES	77,460		241,418		238,852		248,474
Income tax provision	20,144		71,680		61,011		73,185
Equity in earnings of affiliates	3,587		3,233		6,382		5,375
NET INCOME	$ 60,903		$ 172,971		$ 184,223		$ 180,664
EARNINGS PER COMMON SHARE
BASIC (usd per share)	$ 0.71		$ 2.06		$ 2.17		$ 2.15
DILUTED (usd per share)	$ 0.71	[1]	$ 2.04	[1]	$ 2.14	[1]	$ 2.13	[1]
DIVIDENDS DECLARED PER COMMON SHARE (usd per share)	$ 0.23		$ 0.21		$ 0.45		$ 0.42
WEIGHTED AVERAGE SHARES OUTSTANDING
BASIC (in shares)	85,328		84,158		84,940		84,100
DILUTED (in shares)	86,370		84,914		85,982		84,856

[1] There were no anti-dilutive shares excluded from the calculation of diluted earnings per share for the three and six months ended March 31, 2015, and 2014.