Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 889,048	$ 725,343
Changes to goodwill	1,232	153,897
Foreign currency translation	(7,171)	9,808
Balance at the end of the period	883,109	889,048
Harsco Environmental
Goodwill [Roll Forward]
Balance at the beginning of the period	406,401	395,113
Changes to goodwill	0	1,480
Foreign currency translation	(7,171)	9,808
Balance at the end of the period	399,230	406,401
Clean Earth
Goodwill [Roll Forward]
Balance at the beginning of the period	482,647	330,230
Changes to goodwill	1,232	(152,417)
Foreign currency translation	0	0
Balance at the end of the period	$ 483,879	$ 482,647