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Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Income tax expense (benefit)	$ (1,654)	$ 12,601	$ (4,640)	$ 17,814
Unrecognized income tax benefits including interest and penalties	4,000		4,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	300		300
Deferred Tax Assets, Valuation Allowance	2,800		2,800
ESOL
Business Acquisition [Line Items]
Acquisition Costs, Period Cost	8,100		23,900
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Operating Loss Carryforwards	$ 2,800		$ 2,800