Segment Information and Geographic Location Information - Components of Segment Revenues and Segment Adjusted EBITDA (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021
Segment Reporting Information [Line Items]
Segment Revenues		$ 624,208	$ 544,416		$ 546,413
Segment Adjusted EBITDA		78,576	68,450	[1]	77,642	[1]
Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		624,208	544,416		546,413
Segment Adjusted EBITDA		116,452	99,662	[1]	107,724	[1]
Corporate and Other
Segment Reporting Information [Line Items]
Segment Adjusted EBITDA		(37,876)	(31,212)	[1]	(30,082)	[1]
Assessment, Permitting and Response | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		220,727	187,234		261,865
Segment Adjusted EBITDA		52,148	37,458	[1]	57,128	[1]
Measurement and Analysis | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	[2]	197,095	172,432		153,208
Segment Adjusted EBITDA		37,217	31,588	[1],[3]	31,270	[1],[3]
Remediation and Reuse | Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues		206,386	184,750		131,340
Segment Adjusted EBITDA		$ 27,087	$ 30,616	[1]	$ 19,326	[1]

[1] Includes the add back of start-up losses and investment in new services of $2.3 million and $4.4 million for the year ended December 31, 2022 and 2021, respectively.

[2] Includes revenue of $8.8 million, $17.0 million and $23.9 million from the Discontinued Specialty Lab for the year ended December 31, 2023, 2022 and 2021, respectively.

[3] Includes Adjusted EBITDA of $2.1 million and $6.4 million from the Discontinued Specialty Lab for the year ended December 31, 2022 and 2021, respectively.