Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 781,095	$ 805,770	$ 716,583	$ 713,399	$ 805,770	$ 713,399
Other comprehensive income (loss) before reclassifications					(26,117)	6,465
Amounts reclassified from accumulated other comprehensive loss					8,999	12,677
Total other comprehensive income (loss)	(29,126)	12,008	17,913	1,229	(17,118)	19,142
Less: OCI attributable to noncontrolling interests					(3,385)	(393)
Other comprehensive income (loss) attributable to Harsco Corporation					(13,733)	19,535
Ending balance	651,703	781,095	749,383	716,583	651,703	749,383
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(134,889)		(125,392)	(134,889)	(125,392)
Other comprehensive income (loss) before reclassifications					(61,493)	12,150
Amounts reclassified from accumulated other comprehensive loss					0	0
Total other comprehensive income (loss)					(61,493)	12,150
Less: OCI attributable to noncontrolling interests					(3,385)	(393)
Other comprehensive income (loss) attributable to Harsco Corporation					(58,108)	12,543
Ending balance	(192,997)		(112,849)		(192,997)	(112,849)
Effective Portion of Deriviatives Designated as Hedging Instruments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(3,024)		(5,840)	(3,024)	(5,840)
Other comprehensive income (loss) before reclassifications					1,692	(259)
Amounts reclassified from accumulated other comprehensive loss					168	1,182
Total other comprehensive income (loss)					1,860	923
Less: OCI attributable to noncontrolling interests					0	0
Other comprehensive income (loss) attributable to Harsco Corporation					1,860	923
Ending balance	(1,164)		(4,917)		(1,164)	(4,917)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(422,248)		(514,500)	(422,248)	(514,500)
Other comprehensive income (loss) before reclassifications					33,697	(5,451)
Amounts reclassified from accumulated other comprehensive loss					8,831	11,495
Total other comprehensive income (loss)					42,528	6,044
Less: OCI attributable to noncontrolling interests					0	0
Other comprehensive income (loss) attributable to Harsco Corporation					42,528	6,044
Ending balance	(379,720)		(508,456)		(379,720)	(508,456)
Unrealized Loss on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		22		(9)	22	(9)
Other comprehensive income (loss) before reclassifications					(13)	25
Amounts reclassified from accumulated other comprehensive loss					0	0
Total other comprehensive income (loss)					(13)	25
Less: OCI attributable to noncontrolling interests					0	0
Other comprehensive income (loss) attributable to Harsco Corporation					(13)	25
Ending balance	9		16		9	16
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(547,649)	(560,139)	(643,446)	(645,741)	(560,139)	(645,741)
Total other comprehensive income (loss)	(26,223)	12,490	17,240	2,295
Ending balance	$ (573,872)	$ (547,649)	$ (626,206)	$ (643,446)	$ (573,872)	$ (626,206)