Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Total revenues	$ 548,284	$ 600,317
Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	227,205	258,128
Ecoproducts
Disaggregation of Revenue [Line Items]
Total revenues	10,692	36,264
Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Total revenues	5,209	4,727
Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	33,068	29,918
After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	22,915	30,876
Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	13,964	14,374
Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Total revenues	197,971	191,910
Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Total revenues	37,260	34,120
North America
Disaggregation of Revenue [Line Items]
Total revenues	327,433	354,671
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	124,868	131,647
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	33,924	43,961
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	32,511	37,240
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	25,349	28,349
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,199	4,449
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	548,284	600,317
Operating Segments | Harsco Environmental Segment
Disaggregation of Revenue [Line Items]
Total revenues	243,106	299,119
Operating Segments | Harsco Environmental Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	227,205	258,128
Operating Segments | Harsco Environmental Segment | Ecoproducts
Disaggregation of Revenue [Line Items]
Total revenues	10,692	36,264
Operating Segments | Harsco Environmental Segment | Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Total revenues	5,209	4,727
Operating Segments | Harsco Environmental Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Environmental Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Environmental Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Environmental Segment | Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Environmental Segment | Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Environmental Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	55,226	84,210
Operating Segments | Harsco Environmental Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	97,644	110,275
Operating Segments | Harsco Environmental Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	32,124	42,921
Operating Segments | Harsco Environmental Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	28,564	28,915
Operating Segments | Harsco Environmental Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	25,349	28,349
Operating Segments | Harsco Environmental Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,199	4,449
Operating Segments | Clean Earth Segment
Disaggregation of Revenue [Line Items]
Total revenues	235,231	226,030
Operating Segments | Clean Earth Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Ecoproducts
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Total revenues	197,971	191,910
Operating Segments | Clean Earth Segment | Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Total revenues	37,260	34,120
Operating Segments | Clean Earth Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	235,231	226,030
Operating Segments | Clean Earth Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Clean Earth Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment
Disaggregation of Revenue [Line Items]
Total revenues	69,947	75,168
Operating Segments | Harsco Rail Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | Ecoproducts
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	33,068	29,918
Operating Segments | Harsco Rail Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	22,915	30,876
Operating Segments | Harsco Rail Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	13,964	14,374
Operating Segments | Harsco Rail Segment | Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	36,976	44,431
Operating Segments | Harsco Rail Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	27,224	21,372
Operating Segments | Harsco Rail Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	1,800	1,040
Operating Segments | Harsco Rail Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	3,947	8,325
Operating Segments | Harsco Rail Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Rail Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0