Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 423,155	$ 351,563	$ 1,103,955	$ 1,015,910
On-site services and material logistics, product quality improvement and resource recovery for iron, steel and metals manufacturing; value- added environmental solutions for industrial co-products as well as aluminum dross and scrap processing systems
Disaggregation of Revenue [Line Items]
Total revenues	260,883	268,881	791,533	805,924
Specialty waste processing and beneficial reuse solutions for hazardous wastes, contaminated materials and dredged volumes
Disaggregation of Revenue [Line Items]
Total revenues	87,639	0	87,639	0
Railway track maintenance equipment; after-market parts; safety and diagnostic technology and contracting services
Disaggregation of Revenue [Line Items]
Total revenues	74,633	82,682	224,783	209,912
General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0		74
North America
Disaggregation of Revenue [Line Items]
Total revenues	222,638	141,667	489,742	380,620
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	103,835	108,131	321,085	330,223
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	35,678	37,295	110,305	118,305
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	41,279	44,855	123,788	128,217
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	15,302	12,370	44,959	36,073
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,423	7,245	14,076	22,472
Operating Segments | Harsco Environmental Segment
Disaggregation of Revenue [Line Items]
Total revenues	260,883	268,881	791,533	805,924
Operating Segments | Harsco Environmental Segment | On-site services and material logistics, product quality improvement and resource recovery for iron, steel and metals manufacturing; value- added environmental solutions for industrial co-products as well as aluminum dross and scrap processing systems
Disaggregation of Revenue [Line Items]
Total revenues	260,883	268,881	791,533	805,924
Operating Segments | Harsco Environmental Segment | Specialty waste processing and beneficial reuse solutions for hazardous wastes, contaminated materials and dredged volumes
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | Railway track maintenance equipment; after-market parts; safety and diagnostic technology and contracting services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0		0
Operating Segments | Harsco Environmental Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	78,076	78,844	229,537	229,771
Operating Segments | Harsco Environmental Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	93,426	97,411	290,125	291,742
Operating Segments | Harsco Environmental Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	35,127	36,165	108,390	115,011
Operating Segments | Harsco Environmental Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	34,529	36,846	104,446	110,855
Operating Segments | Harsco Environmental Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	15,302	12,370	44,959	36,073
Operating Segments | Harsco Environmental Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,423	7,245	14,076	22,472
Operating Segments | Harsco Clean Earth Segment
Disaggregation of Revenue [Line Items]
Total revenues	87,639	0	87,639	0
Operating Segments | Harsco Clean Earth Segment | On-site services and material logistics, product quality improvement and resource recovery for iron, steel and metals manufacturing; value- added environmental solutions for industrial co-products as well as aluminum dross and scrap processing systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Specialty waste processing and beneficial reuse solutions for hazardous wastes, contaminated materials and dredged volumes
Disaggregation of Revenue [Line Items]
Total revenues	87,639	0	87,639	0
Operating Segments | Harsco Clean Earth Segment | Railway track maintenance equipment; after-market parts; safety and diagnostic technology and contracting services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0		0
Operating Segments | Harsco Clean Earth Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	87,639	0	87,639	0
Operating Segments | Harsco Clean Earth Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment
Disaggregation of Revenue [Line Items]
Total revenues	74,633	82,682	224,783	209,912
Operating Segments | Harsco Rail Segment | On-site services and material logistics, product quality improvement and resource recovery for iron, steel and metals manufacturing; value- added environmental solutions for industrial co-products as well as aluminum dross and scrap processing systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Specialty waste processing and beneficial reuse solutions for hazardous wastes, contaminated materials and dredged volumes
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Railway track maintenance equipment; after-market parts; safety and diagnostic technology and contracting services
Disaggregation of Revenue [Line Items]
Total revenues	74,633	82,682	224,783	209,912
Operating Segments | Harsco Rail Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0		0
Operating Segments | Harsco Rail Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	56,923	62,823	172,566	150,775
Operating Segments | Harsco Rail Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	10,409	10,720	30,960	38,481
Operating Segments | Harsco Rail Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	551	1,130	1,915	3,294
Operating Segments | Harsco Rail Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	6,750	8,009	19,342	17,362
Operating Segments | Harsco Rail Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	74
Corporate | On-site services and material logistics, product quality improvement and resource recovery for iron, steel and metals manufacturing; value- added environmental solutions for industrial co-products as well as aluminum dross and scrap processing systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Specialty waste processing and beneficial reuse solutions for hazardous wastes, contaminated materials and dredged volumes
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Railway track maintenance equipment; after-market parts; safety and diagnostic technology and contracting services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0		74
Corporate | North America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	74
Corporate | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0