Financial Instruments & Related Fair Value (Details) MMBTU in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2015 USD ($) MMBTU	Jul. 31, 2014 USD ($)	Jul. 31, 2015 USD ($) MMBTU	Jul. 31, 2014 USD ($)	Oct. 31, 2014 USD ($) MMBTU
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long gas purchase options providing total coverage | MMBTU	27.4		27.4		29.2
Fair value measurement transfers between levels activity	$ 0	$ 0
Derivative Liability	0		$ 0		$ 0
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0		0		0
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0		0		0
ASSETS
Debt and equity securities held as trading securities	5,005,000		5,005,000		3,941,000
Long-term debt, carry amount	1,425,000,000		1,425,000,000		1,425,000,000
Long-term debt, fair value	1,615,953,000		1,615,953,000		1,617,453,000
Discount on issuance of notes	550,000		550,000		570,000
Current Assets, Gas purchase derivative assets	1,140,000		1,140,000		4,898,000
Gas purchase options	(1,007,000)	(515,000)	(3,296,000)	$ 7,311,000
Amount Of Gain (Loss) Deferred Under PGA Procedures	(1,007,000)	$ (515,000)	$ (3,296,000)	$ 7,311,000
Percentage of annual gas costs approved for recovery under TIP			1.00%
Concentration Risk [Line Items]
Concentration risk, description			“Trade accounts receivable” in “Current Assets” in the Condensed Consolidated Balance Sheets
Fair Value, Measurements, Recurring
ASSETS
Derivatives held for utility operations	1,140,000		$ 1,140,000		4,898,000
Total fair value assets	6,145,000		6,145,000		8,839,000
Money markets | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	503,000		503,000		469,000
Mutual funds | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	4,502,000		4,502,000		3,472,000
Quoted Prices in Active Markets (Level 1) | Fair Value, Measurements, Recurring
ASSETS
Derivatives held for utility operations	1,140,000		1,140,000		4,898,000
Total fair value assets	6,145,000		6,145,000		8,839,000
Quoted Prices in Active Markets (Level 1) | Money markets | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	503,000		503,000		469,000
Quoted Prices in Active Markets (Level 1) | Mutual funds | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	4,502,000		4,502,000		3,472,000
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
ASSETS
Derivatives held for utility operations	0		0		0
Total fair value assets	0		0		0
Significant Other Observable Inputs (Level 2) | Money markets | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	0		0		0
Significant Other Observable Inputs (Level 2) | Mutual funds | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	0		0		0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
ASSETS
Derivatives held for utility operations	0		0		0
Total fair value assets	0		0		0
Significant Unobservable Inputs (Level 3) | Money markets | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	0		0		0
Significant Unobservable Inputs (Level 3) | Mutual funds | Fair Value, Measurements, Recurring
ASSETS
Debt and equity securities held as trading securities	0		0		$ 0
Accounts Receivable
Concentration Risk [Line Items]
Concentration risk amount	$ 7,100,000		$ 7,100,000
Accounts Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%