Goodwill and Identifiable Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2020

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, 2018	$	235,182	$	—	$	235,182
Acquisitions and purchase price adjustments (See Note 5)		579		96,686		97,265
Impact of segment reorganization		(1,101)		1,101		—
Balance at December 31, 2019		234,660		97,787		332,447
Acquisitions and purchase price adjustments (See Note 5)		72,788		59,157		131,945
Balance at December 31, 2020	$	307,448	$	156,944	$	464,392

Schedule of components of identifiable intangible assets

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

	Weighted-Average	December 31, 2020				December 31, 2019
	Remaining Useful Lives	Gross Book		Accumulated		Gross Book		Accumulated
	in Years	Value		Amortization		Value		Amortization
Customer Relationships	8.0	$	255,692	$	(103,919)	$	183,061	$	(80,813)
Backlog	2.0		19,800		(12,600)		7,400		(6,388)
Trade Names	20.5		91,495		(18,661)		71,995		(15,281)
Total	11.7	$	366,987	$	(135,180)	$	262,456	$	(102,482)

Schedule of future amortization expense of identifiable intangible assets

As of December 31, 2020, future amortization expense of identifiable intangible assets was as follows (in thousands):

Year ended December 31—
2021	$	32,344
2022		27,412
2023		23,514
2024		22,164
2025		19,977
Thereafter		106,396
Total	$	231,807