Goodwill and Intangible Assets - Schedule of Amounts Related to Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Goodwill [Line Items]
Balance	$ 274,667
Goodwill acquired during the period	7,532
Balance	282,199
Assessment, Permitting and Response
Goodwill [Line Items]
Balance	162,156
Balance	162,156
Measurement and Analysis
Goodwill [Line Items]
Balance	69,054
Balance	69,054
Remediation and Reuse Segment
Goodwill [Line Items]
Balance	43,457
Goodwill acquired during the period	7,532
Balance	$ 50,989