Number of customers acquired through acquisition

No definition available.

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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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).

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Summary of Accounting Policies Acquisitions Additional information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Revenues	$ 227,616	$ 239,356
Operating Income (Loss)	43,993	40,406
Marlin and Ohl [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred			$ 18,400
Unregulated Energy [Member]
Business Acquisition [Line Items]
Operating Income (Loss)	$ 15,127	$ 13,684
Unregulated Energy [Member] \| Ohl [Member]
Business Acquisition [Line Items]
Goodwill, Acquired During Period			$ 1,500
Number of customers acquired through acquisition			2,500
Unregulated Energy [Member] \| Marlin [Member]
Business Acquisition [Line Items]
Goodwill, Acquired During Period			$ 4,800