Goodwill and Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2021

Amounts related to goodwill are as follows:

	Assessment, Permitting and Response		Measurement and Analysis		Remediation and Reuse		Total
Balance as of December 31, 2020	$	162,156	$	69,054	$	43,457	$	274,667
Goodwill acquired during the period		—		5,013		7,613		12,626
Balance as of June 30, 2021	$	162,156	$	74,067	$	51,070	$	287,293

Amounts related to finite-lived intangible assets are as follows:

June 30, 2021	Estimated Useful Life	Gross Balance		Accumulated Amortization		Total Intangible Assets—Net
Finite lived intangible assets
Customer relationships	2-15 years	$	175,158	$	63,157	$	112,001
Covenants not to compete	4-5 years		31,104		23,403		7,701
Trade names	1-5 years		18,743		13,920		4,823
Proprietary software	3-5 years		21,272		8,592		12,680
Patent	16 years		17,479		1,944		15,535
Total other intangible assets —net		$	263,756	$	111,016	$	152,740

December 31, 2020	Estimated Useful Life	Gross Balance		Accumulated Amortization		Total Intangible Assets—Net
Finite lived intangible assets
Customer relationships	7-15 years	$	164,782	$	53,446	$	111,336
Covenants not to compete	4-5 years		29,942		21,469		8,473
Trade names	1-5 years		16,938		12,849		4,089
Proprietary software	3-5 years		21,007		6,132		14,875
Patent	16 years		17,479		1,398		16,081
Total other intangible assets —net		$	250,148	$	95,294	$	154,854

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