Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Statement of Comprehensive Income [Abstract]
Operating Revenues (1)	[1]	$ 350,186	$ 424,924	$ 811,523	$ 1,032,196
Cost of Gas (1)	[1]	125,822	199,303	300,910	536,505
Margin		224,364	225,621	510,613	495,691
Operating Expenses:
Operations and maintenance		75,508	71,424	146,808	137,574
Depreciation		34,045	31,689	67,730	63,583
General taxes		10,882	10,976	20,804	20,972
Utility income taxes		32,089	36,409	93,999	92,680
Total operating expenses		152,524	150,498	329,341	314,809
Operating Income		71,840	75,123	181,272	180,882
Other Income (Expense):
Income from equity method investments		14,586	15,842	23,787	24,107
Non-operating income		936	631	1,265	1,261
Non-operating expense		(1,511)	(1,197)	(2,238)	(1,897)
Income taxes		(5,835)	(5,916)	(9,212)	(9,180)
Total other income (expense)		8,176	9,360	13,602	14,291
Utility Interest Charges:
Interest on long-term debt		18,823	17,460	37,662	34,950
Allowance for borrowed funds used during construction		(3,292)	(2,804)	(6,097)	(5,076)
Other		1,053	3,425	2,087	5,919
Total utility interest charges		16,584	18,081	33,652	35,793
Net Income		63,432	66,402	161,222	159,380
Other Comprehensive Income (Loss), net of tax:
Unrealized loss from hedging activities of equity method investments, net of tax of ($202) and ($201) for the three months ended April 30, 2016 and 2015, respectively, and ($293) and ($801) for the six months ended April 30, 2016 and 2015, respectively		(324)	(316)	(462)	(1,260)
Reclassification adjustment of realized loss from hedging activities of equity method investments included in net income, net of tax of $107 and $286 for the three months ended April 30, 2016 and 2015, respectively, and $434 and $361 for the six months ended April 30, 2016 and 2015, respectively		170	449	675	566
Net current period benefit activities of equity method investments, net of tax of $1 and ($25) for the three months ended April 30, 2016 and 2015, respectively, and $2 and ($25) for the six months ended April 30, 2016 and 2015, respectively		1	(39)	2	(39)
Total other comprehensive income (loss)		(153)	94	215	(733)
Comprehensive Income		$ 63,279	$ 66,496	$ 161,437	$ 158,647
Average Shares of Common Stock:
Basic (in shares)		81,109	78,818	81,035	78,717
Diluted (in shares)		81,388	79,115	81,324	79,048
Earnings Per Share of Common Stock:
Basic (usd per share)		$ 0.78	$ 0.84	$ 1.99	$ 2.02
Diluted (usd per share)		$ 0.78	$ 0.84	$ 1.98	$ 2.02

[1] See Note 13 for amounts attributable to affiliates.