Segment Information - Components of Segment Revenues and Adjusted EBITDA (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Segment Revenues		$ 131,428	$ 134,680
Segment Adjusted EBITDA		16,603	16,451	[1]
Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		131,428	134,680
Segment Adjusted EBITDA		25,931	23,938	[1]
Assessment, Permitting and Response | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		52,214	45,600
Segment Adjusted EBITDA		14,266	9,623	[1]
Measurement and Analysis | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	[2]	42,527	39,761
Segment Adjusted EBITDA		6,387	6,322	[1],[3]
Remediation and Reuse | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		36,687	49,319
Segment Adjusted EBITDA		5,278	7,993	[1]
Corporate and Other
Segment Reporting Information [Line Items]
Segment Adjusted EBITDA		$ (9,328)	$ (7,487)	[1]

[1] Includes the add back of start-up losses and investment in new services of $0.8 million.

[2] Includes revenue of $1.4 million and $5.6 million from the Discontinuing Specialty Lab, for the three months ended March 31, 2023 and March 31, 2022, respectively.

[3] Includes Adjusted EBITDA of $1.3 million from the Discontinuing Specialty Lab.