Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013
Statement of Comprehensive Income [Abstract]
Operating Revenues (1)	[1]	$ 1,371,718	$ 1,469,988	$ 1,278,229
Cost of Gas (1)	[1]	644,424	779,780	656,739
Margin		727,294	690,208	621,490
Operating Expenses:
Operations and maintenance		294,517	270,877	253,120
Depreciation		128,704	118,996	112,207
General taxes		42,110	37,294	34,635
Utility income taxes		76,934	83,176	77,334
Total operating expenses		542,265	510,343	477,296
Operating Income		185,029	179,865	144,194
Other Income (Expense):
Income from equity method investments		34,461	32,753	26,056
Non-operating income		3,164	1,842	2,839
Non-operating expense		(3,724)	(4,331)	(5,122)
Income taxes		(13,288)	(11,642)	(8,612)
Total other income (expense)		20,613	18,622	15,161
Utility Interest Charges:
Interest on long-term debt		70,619	61,562	54,158
Allowance for borrowed funds used during construction		(11,106)	(16,427)	(30,975)
Other		9,118	9,551	1,755
Total utility interest charges		68,631	54,686	24,938
Net Income		137,011	143,801	134,417
Other Comprehensive Income (Loss), net of tax:
Unrealized gain (loss) from hedging activities of equity method investments, net of tax of ($1,028), $225 and ($69) for the years ended October 31, 2015, 2014 and 2013, respectively		(1,601)	355	(109)
Reclassification adjustment of realized (gain) loss from hedging activities of equity method investments included in net income, net of tax of $652, ($177) and $85 for the years ended October 31, 2015, 2014 and 2013, respectively		1,018	(284)	130
Net current period benefit activities of equity method investments, net of tax of ($23) and ($16) for the years ended October 31, 2015 and 2014, respectively		(35)	(24)
Total other comprehensive income (loss)		(618)	47	21
Comprehensive Income		$ 136,393	$ 143,848	$ 134,438
Average Shares of Common Stock:
Basic (in shares)		78,942	77,883	74,884
Diluted (in shares)		79,231	78,193	75,333
Earnings Per Share of Common Stock:
Basic (usd per share)		$ 1.74	$ 1.85	$ 1.80
Diluted (usd per share)		$ 1.73	$ 1.84	$ 1.78

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