Goodwill and Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2018

Goodwill and Intangible Assets

Schedule of goodwill by reporting unit

The change in goodwill by segment for the six months ended June 30, 2018 was as follows (in thousands):

	Power		Pipeline		Utilities		Transmission		Civil		Total
Balance at January 1, 2018	$	24,391	$	51,521	$	37,312	$	—	$	40,150	$	153,374
Goodwill acquired during the year		6,101		2,849		—		34,747		—		43,697
Balance at June 30, 2018	$	30,492	$	54,370	$	37,312	$	34,747	$	40,150	$	197,071

Summary of intangible asset categories, amounts and the average amortization periods

The table below summarizes the intangible asset categories, amounts and the average amortization periods, which are on a straight-line basis (in thousands):

		June 30, 2018				December 31, 2017
	Weighted Average Life	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Tradename	9 years	$	31,590	$	(23,451)	$	32,175	$	(22,238)
Customer relationships	16 years		102,550		(19,239)		49,900		(16,338)
Non-compete agreements	5 years		3,500		(1,037)		1,900		(820)
Other	3 years		275		(99)		275		(54)
Total	15 years	$	137,915	$	(43,826)	$	84,250	$	(39,450)

Schedule of estimated future amortization expense for intangible assets

Estimated future amortization expense for intangible assets is as follows (in thousands):

	Estimated
	Intangible
For the Years Ending	Amortization
December 31,	Expense
2018 (remaining six months)	$	6,280
2019		12,145
2020		9,394
2021		8,155
2022		6,989
Thereafter		51,126
	$	94,089