XML 26 R12.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Impairment of long-lived assets | 9 Months Ended
--- | ---
Sep. 30, 2016
Asset Impairment Charges [Abstract] |
Impairment of long-lived assets | Impairment of long-lived assets During the second quarter of 2015, the Company recognized an impairment of coalbed natural gas gathering assets at the pipeline and midstream segment of $3.0 million, which is recorded in operation and maintenance expense on the Consolidated Statements of Income. The impairment is related to coalbed natural gas gathering assets located in Wyoming where there had been continued decline in natural gas development and production activity due to low natural gas prices. The coalbed natural gas gathering assets were written down to their estimated fair value that was determined using the income approach. The Company negotiated a purchase and sale agreement for the sale of certain non-strategic natural gas gathering assets at the pipeline and midstream segment and, as a result, recognized an impairment during the third quarter of 2015 of $14.1 million, largely related to these assets, which is recorded in operation and maintenance expense on the Consolidated Statements of Income. The natural gas gathering assets were written down to their estimated fair value that was determined using the market approach. For more information on these nonrecurring fair value measurements, see Note 13. For information regarding impairments related to the Company's discontinued operations, see Note 10.

X
- References No definition available. + Details
Name: | us-gaap_AssetImpairmentChargesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for the details of the charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value. Disclosure may also include a description of the impaired asset and facts and circumstances leading to the impairment, amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired asset is reported. + References No definition available. + Details
Name: | us-gaap_AssetImpairmentChargesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration