Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenues	$ 452,797	$ 447,265
Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	190,746	189,279
Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	227,689	225,060
Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	31,965	29,785
Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	2,397	3,141
North America
Disaggregation of Revenue [Line Items]
Total revenues	261,825	256,460
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	102,079	112,171
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	35,805	30,653
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	28,068	23,370
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	19,886	20,121
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	5,134	4,490
Operating Segments | Harsco Environmental Segment
Disaggregation of Revenue [Line Items]
Total revenues	262,051	257,986
Operating Segments | Harsco Environmental Segment | Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0
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	227,689	225,060
Operating Segments | Harsco Environmental Segment | Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	31,965	29,785
Operating Segments | Harsco Environmental Segment | Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	2,397	3,141
Operating Segments | Harsco Environmental Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	71,079	67,181
Operating Segments | Harsco Environmental Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	102,079	112,171
Operating Segments | Harsco Environmental Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	35,805	30,653
Operating Segments | Harsco Environmental Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	28,068	23,370
Operating Segments | Harsco Environmental Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	19,886	20,121
Operating Segments | Harsco Environmental Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	5,134	4,490
Operating Segments | Harsco Clean Earth Segment
Disaggregation of Revenue [Line Items]
Total revenues	190,746	189,279
Operating Segments | Harsco Clean Earth Segment | Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	190,746	189,279
Operating Segments | Harsco 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 | Harsco Clean Earth Segment | Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	190,746	189,279
Operating Segments | Harsco Clean Earth Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | Harsco Clean Earth Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0