Acquisitions and Dispositions - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended		3 Months Ended								12 Months Ended
	Apr. 06, 2020	Jun. 28, 2019	Jan. 31, 2020	Nov. 30, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 01, 2019
Business Acquisition [Line Items]
Product revenues					$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Operating income from continuing operations													88,376	(3,306)	76,403
Interest Expense													63,235	58,196	34,024
Purchase of businesses, net of cash acquired													0	432,855	623,495
Proceeds from sale of businesses													0	37,219	658,414
Receivable with Imputed Interest, Face Amount			$ 40,000
Receivables, Fair Value Disclosure			34,300		32,300								32,300
Income (loss) from discontinued businesses													0	18,281	569,135
Revenues													1,848,399	1,534,033	1,204,369
Provision for Loss on Contracts					$ 33,400								$ 33,400
SBB
Business Acquisition [Line Items]
Revenues
SBB | Contract 2
Business Acquisition [Line Items]
Percentage Complete					78.00%								78.00%
Network Rail | Contract 2
Business Acquisition [Line Items]
Percentage Complete					42.00%								42.00%
Deutsche Bahn | Contract 2
Business Acquisition [Line Items]
Percentage Complete					18.00%								18.00%
Clean Earth
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Purchase price		$ 628,000
Business Combination, Additional Expense Related To Reimbursement of NOL, Fair Value													$ 8,000	11,000
Tax deductible Goodwill		16,300
Costs associated with the acquisition														15,200
Business Combination, Consideration Transferred		$ 625,000
Business Combination, Contingent Consideration Arrangements, Post-Closing Period		5 years
ESOL
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Purchase price	$ 429,000
Tax deductible Goodwill	$ 36,800
Costs associated with the acquisition													49,000	7,300
Harsco Industrial | Discontinued Operations, Held-for-sale
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Corporate Overhead															4,000
Income (loss) from discontinued businesses													0	18,281	569,135
Harsco Industrial Patterson-Kelley [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Net Gain on Disposal, After Tax				$ 33,000
Disposal Group, Net Gain on Disposal, Before Tax				41,200
Proceeds from sale of businesses				$ 60,000
Harsco Industrial IKG | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			85,000
Disposal Group, Net Gain on Disposal, After Tax			9,000
Receivable with Imputed Interest, Face Amount			40,000
Income (loss) from discontinued businesses			$ 18,400
Harsco Industrial Air-X-Changers Business [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Consideration																$ 600,000
Disposal Group, Net Gain on Disposal, After Tax																421,000
Disposal Group, Net Gain on Disposal, Before Tax																$ 527,900
Harsco Rail | Discontinued Operations, Held-for-sale
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Corporate Overhead													$ 4,200	$ 4,200	$ 4,200