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Number of separate joint ventures.

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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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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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Nature of Business (Details) $ in Thousands					6 Months Ended
Nature of Business (Details) $ in Thousands	Jun. 01, 2018 USD ($) segment	Jun. 16, 2017 USD ($)	May 30, 2017 USD ($)	May 26, 2017 USD ($)	Jun. 30, 2018 USD ($) segment item	Jun. 30, 2017 USD ($)
Nature of Business
Number of reportable segments \| segment					5
Number of joint ventures \| item					2
Number of variable interest entities \| item					2
Purchase consideration, net of cash acquired					$ 111,030	$ 66,205
Willbros Group, Inc
Nature of Business
Number of reportable segments \| segment	3
Purchase consideration, net of cash acquired	$ 111,030
Total purchase consideration	164,758
Transmission \| Willbros Group, Inc
Nature of Business
Purchase consideration, net of cash acquired	$ 111,000
Utilities \| FGC
Nature of Business
Total purchase consideration				$ 37,700
Pipeline \| Coastal
Nature of Business
Total purchase consideration		$ 27,500
Power \| Engineering Assets
Nature of Business
Total purchase consideration			$ 2,300
Carlsbad
Nature of Business
Ownership percentage					50.00%
Wilmington
Nature of Business
Ownership percentage					50.00%