Goodwill and Identifiable Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill and Identifiable Intangible Assets, Net

Schedule of changes in the carrying amount of goodwill

The changes in the carrying amount of goodwill are as follows (in thousands):

	Mechanical Services		Electrical Services
	Segment		Segment		Total
Balance at December 31, 2017	$	200,584	$	—	$	200,584
Acquisitions and purchase price adjustments (See Note 4)		34,598		—		34,598
Impairment adjustment		—		—		—
Balance at December 31, 2018		235,182		—		235,182
Acquisitions and purchase price adjustments (See Note 4)		579		96,686		97,265
Impact of segment reorganization		(1,101)		1,101		—
Impairment adjustment		—		—		—
Balance at December 31, 2019	$	234,660	$	97,787	$	332,447

Schedule of components of identifiable intangible assets

Identifiable intangible assets consist of the following (dollars in thousands):

		December 31,
	Estimated	2019				2018
	Useful Lives	Gross Book		Accumulated		Gross Book		Accumulated
	in Years	Value		Amortization		Value		Amortization
Customer relationships	1 - 15	$	183,061	$	(80,813)	$	128,480	$	(60,731)
Backlog	1 - 2		7,400		(6,388)		9,100		(8,260)
Tradenames	2 - 25		71,995		(15,281)		39,395		(12,709)
Total		$	262,456	$	(102,482)	$	176,975	$	(81,700)

Schedule of future amortization expense of identifiable intangible assets

At December 31, 2019, future amortization expense of identifiable intangible assets is as follows (in thousands):

Year ended December 31—
2020	$	23,246
2021		19,191
2022		16,545
2023		15,082
2024		13,732
Thereafter		72,178
Total	$	159,974