Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 623,042	$ 805,770
OCI before reclassifications	2,536	7,136
Amounts reclassified from AOCI, net of tax	4,616	4,872
Total other comprehensive income (loss)	7,152	12,008
Less: OCI attributable to noncontrolling interests	(358)	482
OCI attributable to Harsco Corporation	6,794	12,490
Ending balance	623,952	781,095
Cumulative Foreign Exchange Translation Adjustments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(213,104)	(134,889)
OCI before reclassifications	12,446	(2,847)
Amounts reclassified from AOCI, net of tax	0	0
Total other comprehensive income (loss)	12,446	(2,847)
Less: OCI attributable to noncontrolling interests	(358)	482
OCI attributable to Harsco Corporation	12,088	(2,365)
Ending balance	(201,016)	(137,254)
Effective Portion of Derivatives Designated as Hedging Instruments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	157	(3,024)
OCI before reclassifications	(2,684)	802
Amounts reclassified from AOCI, net of tax	124	338
Total other comprehensive income (loss)	(2,560)	1,140
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	(2,560)	1,140
Ending balance	(2,403)	(1,884)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(354,699)	(422,248)
OCI before reclassifications	(7,227)	9,184
Amounts reclassified from AOCI, net of tax	4,492	4,534
Total other comprehensive income (loss)	(2,735)	13,718
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	(2,735)	13,718
Ending balance	(357,434)	(408,530)
Unrealized Gain (Loss) on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	10	22
OCI before reclassifications	1	(3)
Amounts reclassified from AOCI, net of tax	0	0
Total other comprehensive income (loss)	1	(3)
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	1	(3)
Ending balance	11	19
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(567,636)	(560,139)
Total other comprehensive income (loss)	6,794	12,490
Ending balance	$ (560,842)	$ (547,649)