Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	$ 713,399	$ 789,659	$ 313,376
OCI before reclassifications	58,995	(92,545)
Amounts reclassified from AOCI, net of tax	25,110	37,238
Total OCI	84,105	(55,307)	(58)
Plus: OCI attributable to noncontrolling interests	1,497	(2,812)
OCI attributable to Harsco Corporation	85,602	(58,119)
Balances	805,770	713,399	789,659
Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances			0
Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(587,622)
Balances			(587,622)
Cumulative Foreign Exchange Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(125,392)
OCI before reclassifications	(10,994)	7,854
Amounts reclassified from AOCI, net of tax		12,906
Total OCI	(10,994)	20,760
Plus: OCI attributable to noncontrolling interests	1,497	(2,812)
OCI attributable to Harsco Corporation	(9,497)	17,948
Balances	(134,889)	(125,392)
Cumulative Foreign Exchange Translation Adjustments | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(143,340)
Balances			(143,340)
Effective Portion of Derivatives Designated as Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(5,840)
OCI before reclassifications	441	(3,709)
Amounts reclassified from AOCI, net of tax	2,375	1,586
Total OCI	2,816	(2,123)
Plus: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	2,816	(2,123)
Balances	(3,024)	(5,840)
Effective Portion of Derivatives Designated as Hedging Instruments | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(3,717)
Balances			(3,717)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(514,500)
OCI before reclassifications	69,517	(96,684)
Amounts reclassified from AOCI, net of tax	22,735	22,746
Total OCI	92,252	(73,938)
Plus: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	92,252	(73,938)
Balances	(422,248)	(514,500)
Cumulative Unrecognized Actuarial Losses on Pension Obligations | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(440,562)
Balances			(440,562)
Unrealized Loss on Marketable Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(9)
OCI before reclassifications	31	(6)
Amounts reclassified from AOCI, net of tax		0
Total OCI	31	(6)
Plus: OCI attributable to noncontrolling interests		0
OCI attributable to Harsco Corporation	31	(6)
Balances	22	(9)
Unrealized Loss on Marketable Securities | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(3)
Balances			(3)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(645,741)	(587,622)	(567,107)
Total OCI	85,602	(58,119)	914
Balances	$ (560,139)	$ (645,741)	(587,622)
Total | Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances			$ (21,429)