Goodwill and Intangible Assets (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets

Schedule of goodwill by reporting unit

The change in goodwill by segment for the nine months ended September 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		7,645		3,570		—		43,541		—		54,756
Balance at September 30, 2018	$	32,036	$	55,091	$	37,312	$	43,541	$	40,150	$	208,130

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):

		September 30, 2018				December 31, 2017
	Weighted Average Life	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Tradename	9 years	$	31,390	$	(24,272)	$	32,175	$	(22,238)
Customer relationships	16 years		97,400		(21,146)		49,900		(16,338)
Non-compete agreements	5 years		3,500		(1,212)		1,900		(820)
Other	3 years		275		(122)		275		(54)
Total	15 years	$	132,565	$	(46,752)	$	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 three months)	$	3,015
2019		11,879
2020		9,134
2021		7,897
2022		6,736
Thereafter		47,152
	$	85,813