Segment Information - Components of Segment Revenues and Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Segment Revenues	$ 133,817	$ 61,031
Segment Adjusted EBITDA	16,800	5,553
Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	133,817	61,031
Segment Adjusted EBITDA	23,145	10,928
Assessment, Permitting and Response | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	75,262	4,530
Segment Adjusted EBITDA	15,804	1,442
Measurement and Analysis | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	33,440	36,440
Segment Adjusted EBITDA	4,860	7,379
Remediation and Reuse | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	25,115	20,061
Segment Adjusted EBITDA	2,481	2,107
Corporate and Other
Segment Reporting Information [Line Items]
Segment Adjusted EBITDA	$ (6,345)	$ (5,375)