Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

The information in the following table is derived from the segment’s internal financial reports used for corporate management purposes:  

	For the Year Ended December 31,
(in thousands)	2017			2016			2015
Contract revenues:
T&D	$	879,372		$	818,972		$	794,898
C&I		523,945			323,515			266,783
	$	1,403,317		$	1,142,487		$	1,061,681
Income from operations:
T&D	$	39,631		$	63,459		$	63,155
C&I		25,048			13,920			13,592
General Corporate		(35,121	)		(38,625	)		(31,906	)
	$	29,558		$	38,754		$	44,841

Reconciliation of Assets from Segment to Consolidated [Table Text Block]

Identifiable assets, consisting of contract receivables, costs and estimated earnings in excess of billings on uncompleted contracts, construction materials inventory, goodwill and intangibles for each segment are as follows as of December 31:

(in thousands)	2017		2016
T&D	$	257,834	$	235,548
C&I		152,207		125,696
General Corporate		193,747		212,251
	$	603,788	$	573,495

Schedule Of Segment Reporting Information Related To Allocation Of Depreciation And Amortization By Segment [Table Text Block]

An allocation of total depreciation, including depreciation of shared construction equipment, and amortization to each segment is as follows:

	For the Year Ended December 31,
(in thousands)	2017		2016		2015
Depreciation and amortization
T&D	$	34,990	$	35,947	$	35,456
C&I		3,586		3,175		2,573
	$	38,576	$	39,122	$	38,029