Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

The total amount of other operating income, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operation.

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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 299,369		$ 710,510		$ 905,063
Other	902		2,270		3,866
Total operating revenues	300,271	$ 297,470	712,780	$ 720,648	908,929	$ 908,685
Retail
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	265,971		633,578		807,626
Wholesale
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	28,253		63,354		79,456
Wheeling (transmission)
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 5,145		$ 13,578		$ 17,981