Acquisitions and Dispositions - Preliminary Valuation of Identifiable Intangible Assets and Amortization Periods (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 06, 2020	Mar. 31, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 523,318	$ 523,048
Permits and rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		308,779	308,705
Non-compete agreement
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		2,500	$ 2,500
ESOL | Permits and rights
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	22 years
Preliminary Valuation	$ 138,000	138,000
ESOL | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	10 years
Preliminary Valuation	$ 23,000	23,000
ESOL | Non-compete agreement
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	4 years
Harsco Clean Earth Segment | ESOL
Acquired Finite-Lived Intangible Assets [Line Items]
Preliminary Valuation	$ 161,000	161,000
Gross Carrying Amount	2,500	2,500
Total identifiable intangible assets acquired	$ 163,500	163,500
Measurement Period Adjustments
Intangible assets		0
Harsco Clean Earth Segment | ESOL | Non-compete agreement
Measurement Period Adjustments
Permits and rights		0
Customer relationships		0
Intangible assets		0
Total identifiable intangible assets acquired		$ 0