Reconciliation of Basic and Diluted Shares - Reconciliation of Basic and Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Income (loss) from continuing operations attributable to Harsco Corporation common stockholders	$ (9,557)	$ (7,333)
Weighted-average shares outstanding - basic (in shares)	79,633	79,363
Dilutive effect of stock-based compensation (in shares)	0	0
Weighted-average shares outstanding - diluted (in shares)	79,633	79,363
Earnings (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders:
Basic (in dollars per share)	$ (0.12)	$ (0.09)
Diluted (in dollars per share)	$ (0.12)	$ (0.09)