Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

The change in goodwill by segment for 2018 and 2017 was as follows (in thousands):


	Power		Pipeline		Utilities		Transmission		Civil		Total
Balance at January 1, 2017	$	24,512	$	42,252	$	20,312	$	—	$	40,150	$	127,226
Goodwill acquired during the year		—		9,269		17,000		—		—		26,269
Purchase price allocation adjustments		(121)		—		—		—		—		(121)
Balance at January 1, 2018	$	24,391	$	51,521	$	37,312	$	—	$	40,150	$	153,374
Goodwill acquired during the year		1,542		764		—		50,479		—		52,785
Balance at December 31, 2018	$	25,933	$	52,285	$	37,312	$	50,479	$	40,150	$	206,159

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 generally on a straight-line basis (in thousands):


		December 31, 2018						December 31, 2017
	Weighted Average Life	Gross Carrying Amount		Accumulated Amortization		Intangible assets, net		Gross Carrying Amount		Accumulated Amortization		Intangible assets, net
Tradename	9 years	$	31,390	$	(25,156)	$	6,234	$	32,175	$	(22,238)	$	9,937
Customer relationships	16 years		97,400		(23,079)		74,321		49,900		(16,338)		33,562
Non-compete agreements	5 years		1,900		(1,387)		513		1,900		(820)		1,080
Other	3 years		275		(145)		130		275		(54)		221
Total	15 years	$	130,965	$	(49,767)	$	81,198	$	84,250	$	(39,450)	$	44,800

Schedule of estimated future amortization expense for intangible assets

In the second quarter of 2017, we recorded a $0.5 million impairment charge related to a tradename intangible asset in our Pipeline segment. The impairment charge is included in “Selling, general and administrative expenses” in the Consolidated Statements of Income. Estimated future amortization expense for intangible assets as of December 31, 2018 is as follows (in thousands):


	Estimated
	Intangible
	Amortization
For the Years Ending December 31,	Expense
2019	$	11,559
2020		8,814
2021		7,577
2022		6,416
2023		5,394
Thereafter		41,438
	$	81,198