| **Regulatory Matters Regulatory Matters (Tables)** | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
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| **Regulated Operations [Abstract]**                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Schedule of Regulatory Assets                      | Regulatory assets and liabilities in the Condensed Consolidated Balance Sheets as of July 31, 2016 and October 31, 2015 are as follows.In thousandsJuly 31, 2016 October 31, 2015Regulatory Assets:   Current:   Unamortized debt expense on reacquired debt$238 $238Amounts due from customers34,621 —Environmental costs1,516 1,513Deferred operations and maintenance expenses889 847Deferred pipeline integrity expenses3,470 3,470Deferred pension and other retirement benefit costs2,757 2,757Robeson liquefied natural gas (LNG) development costs223 381Derivatives - gas supply contracts held for utility operations33,300 —Other1,406 1,730Total current78,420 10,936Noncurrent:   Unamortized debt expense on reacquired debt4,488 4,666Environmental costs3,989 5,107Deferred operations and maintenance expenses3,325 3,997Deferred pipeline integrity expenses31,533 29,824Deferred pension and other retirement benefit costs17,509 17,861Amounts not yet recognized as a component of pension and other retirement benefit costs109,884 114,854Regulatory cost of removal asset19,925 19,087Robeson LNG development costs— 127Derivatives - gas supply contracts held for utility operations149,600 —Other871 1,203Total noncurrent341,124 196,726Total$419,544 $207,662 |
| Schedule of Regulatory Liabilities                 | Regulatory Liabilities:   Current:   Amounts due to customers$3,908 $13,367Noncurrent:   Regulatory cost of removal obligations533,844 521,478Deferred income taxes64,827 68,738Amounts not yet recognized as a component of pension and other retirement benefit costs78 85Total noncurrent598,749 590,301Total$602,657$603,668Regulatory assets and liabilities in the Condensed Consolidated Balance Sheets as of July 31, 2016 and October 31, 2015 are as follows.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |

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| - Definition
Tabular disclosure of assets that are created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet.
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| - Definition
Tabular disclosure of regulatory liabilities. Detailed information about liabilities that result from rate actions of a regulator. Rate actions of a regulator can impose a liability on a regulated enterprise resulting in a regulatory liability.
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