Information by Segment and Geographic Area (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) Customer segment	Dec. 31, 2020 USD ($) Customer	Dec. 31, 2019 USD ($) Customer
Revenue, Major Customer [Line Items]
Revenues	$ 1,848,399	$ 1,534,033	$ 1,204,369
Number of reportable segments | segment	2
Number of major customers | Customer	1
Harsco Environmental
Revenue, Major Customer [Line Items]
Number of major customers | Customer	1	1	1
Clean Earth
Revenue, Major Customer [Line Items]
Number of major customers | Customer	1	0
All Other
Revenue, Major Customer [Line Items]
Revenues	$ 722,181	$ 586,909	$ 656,753
U.S. Plans
Revenue, Major Customer [Line Items]
Revenues	1,008,689	830,699	420,956
United Kingdom
Revenue, Major Customer [Line Items]
Revenues	$ 117,529	$ 116,425	$ 126,660