Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

9. GOODWILL AND INTANGIBLE ASSETS

Amounts related to goodwill as of December 31, are as follows:


	Assessment, Permitting and Response			Measurements and Analysis			Remediation and Reuse			Total
Balance as of December 31, 2022	$	185,116		$	86,205		$	52,547		$	323,868
Goodwill acquired during the year		—			7,691			33,095			40,786
Prior year acquisitions measurement period adjustments (Note 8)		(170	)		(6	)		17			(159	)
Foreign currency translation impact		—			—			(46	)		(46	)
Balance as of December 31, 2023	$	184,946		$	93,890		$	85,613		$	364,449

Amounts related to finite-lived intangible assets as of December 31, are as follows:


2023	Estimated Useful Life	Gross Balance		Accumulated Amortization		Total Intangible Assets—Net
Finite lived intangible assets
Customer relationships	2–15 years	$	227,986	$	116,226	$	111,760
Covenants not to compete	4–5 years		36,250		30,889		5,361
Trade names	1–5 years		24,434		20,719		3,714
Proprietary software	3–5 years		26,486		19,309		7,177
Patent	16 years		17,479		4,678		12,801
Total other intangible assets—net		$	332,635	$	191,821	$	140,813


2022	Estimated Useful Life	Gross Balance		Accumulated Amortization		Total Intangible Assets—Net
Finite lived intangible assets
Customer relationships	2–15 years	$	208,024	$	95,768	$	112,256
Covenants not to compete	4–5 years		33,542		28,280		5,262
Trade names	1–5 years		22,061		18,256		3,805
Proprietary software	3–5 years		22,698		15,810		6,888
Patent	16 years		17,479		3,583		13,896
Total other intangible assets—net		$	303,804	$	161,697	$	142,107

Intangible assets with finite lives are stated at cost, less accumulated amortization and impairment losses, if any. These intangible assets are amortized using the straight-line method over the estimated useful lives of the assets.

Amortization expense for the years ended December 31, 2023, 2022, and 2021 was $30.1 million, $36.1 million and $35.2 million, respectively.

Future amortization expense is estimated to be as follows for each of the five following years and thereafter ending December 31:


2024		28,119
2025		20,815
2026		16,266
2027		15,597
2028		12,795
Thereafter		47,221
Total	$	140,813