Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 447,288	$ 408,038
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	261,312	264,723
Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	68,591	59,678
Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	76,203	44,267
Industrial grating and fencing products
Disaggregation of Revenue [Line Items]
Total revenues	33,376	30,097
Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	7,806	9,234
General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		39
North America
Disaggregation of Revenue [Line Items]
Total revenues	235,814	190,367
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	108,234	111,641
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	42,868	47,031
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	41,759	39,941
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	13,915	11,553
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,698	7,505
Harsco Metals & Minerals Segment
Disaggregation of Revenue [Line Items]
Total revenues	261,312	264,723
Harsco Metals & Minerals 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	261,312	264,723
Harsco Metals & Minerals Segment | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Metals & Minerals Segment | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Metals & Minerals Segment | Industrial grating and fencing products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Metals & Minerals Segment | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Metals & Minerals Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0
Harsco Metals & Minerals Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	73,349	71,065
Harsco Metals & Minerals Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	98,221	96,921
Harsco Metals & Minerals Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	36,991	41,458
Harsco Metals & Minerals Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	34,138	36,221
Harsco Metals & Minerals Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	13,915	11,553
Harsco Metals & Minerals Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,698	7,505
Harsco Industrial Segment
Disaggregation of Revenue [Line Items]
Total revenues	117,385	83,598
Harsco Industrial 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
Harsco Industrial Segment | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Industrial Segment | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	76,203	44,267
Harsco Industrial Segment | Industrial grating and fencing products
Disaggregation of Revenue [Line Items]
Total revenues	33,376	30,097
Harsco Industrial Segment | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	7,806	9,234
Harsco Industrial Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0
Harsco Industrial Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	112,099	78,858
Harsco Industrial Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Industrial Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	5,286	4,740
Harsco Industrial Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Industrial Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Industrial Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Rail Segment
Disaggregation of Revenue [Line Items]
Total revenues	68,591	59,678
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
Harsco Rail Segment | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	68,591	59,678
Harsco Rail Segment | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Rail Segment | Industrial grating and fencing products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Rail Segment | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Rail Segment | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		0
Harsco Rail Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	50,366	40,405
Harsco Rail Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	10,013	14,720
Harsco Rail Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	591	833
Harsco Rail Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	7,621	3,720
Harsco Rail Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Harsco Rail Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	39
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
Corporate | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Industrial grating and fencing products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues		39
Corporate | North America
Disaggregation of Revenue [Line Items]
Total revenues	0	39
Corporate | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Corporate | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0