Goodwill and Intangible Assets - Schedule of Amounts Related to Goodwill (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Goodwill [Line Items]
Balance	$ 127,058
Goodwill acquired during the period	146,038
Balance	273,096
Assessment, Permitting and Response
Goodwill [Line Items]
Balance	15,173
Goodwill acquired during the period	146,038
Balance	161,211
Measurement and Analysis
Goodwill [Line Items]
Balance	68,628
Balance	68,628
Remediation and Reuse Segment
Goodwill [Line Items]
Balance	43,257
Balance	$ 43,257