Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 6,989	$ (1,654)	$ 19,782	$ (4,640)
Unrecognized income tax benefits including interest and penalties	4,300		4,300
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 300		$ 300
Harsco Clean Earth Segment
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards		$ 2,800		$ 2,800