Revenue Recognition - Summary of Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,722,380	$ 1,607,062	$ 1,451,223
Revenues	1,722,380	1,607,062	1,451,223
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	1,068,304	1,011,328	965,540
Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	279,294	295,999	238,107
Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	207,184	144,955	93,616
Industrial grating products
Disaggregation of Revenue [Line Items]
Total revenues	127,419	116,598	115,914
Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	40,105	38,039	38,012
General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	74	143	34
North America
Disaggregation of Revenue [Line Items]
Total revenues	862,082	744,961	654,369
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	438,856	448,461	418,606
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	176,013	183,326	164,341
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	167,850	160,666	136,862
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	50,003	42,700	46,731
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	27,576	26,948	30,314
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	74	143	34
Revenues	74	143	34
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
Corporate | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Industrial grating products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	74	143	34
Corporate | North America
Disaggregation of Revenue [Line Items]
Total revenues	74	143	34
Corporate | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	1,068,304	1,011,328	965,540
Revenues	1,068,304	1,011,328	965,540
Harsco Metals & Minerals | Operating segments | 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	1,068,304	1,011,328	965,540
Harsco Metals & Minerals | Operating segments | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments | Industrial grating products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Metals & Minerals | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	302,238	274,476	247,287
Harsco Metals & Minerals | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	390,840	369,763	388,336
Harsco Metals & Minerals | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	151,886	159,130	134,071
Harsco Metals & Minerals | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	145,761	138,311	119,873
Harsco Metals & Minerals | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	50,003	42,700	45,659
Harsco Metals & Minerals | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	27,576	26,948	30,314
Harsco Industrial | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	374,708	299,592	247,542
Revenues	374,708	299,592	247,542
Harsco Industrial | Operating segments | 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
Harsco Industrial | Operating segments | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Industrial | Operating segments | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	207,184	144,955	93,616
Harsco Industrial | Operating segments | Industrial grating products
Disaggregation of Revenue [Line Items]
Total revenues	127,419	116,598	115,914
Harsco Industrial | Operating segments | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	40,105	38,039	38,012
Harsco Industrial | Operating segments | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Industrial | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	354,558	273,775	215,322
Harsco Industrial | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Industrial | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	20,150	21,369	28,256
Harsco Industrial | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	4,448	3,964
Harsco Industrial | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Industrial | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	279,294	295,999	238,107
Revenues	279,294	295,999	238,107
Harsco Rail | Operating segments | 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
Harsco Rail | Operating segments | Railway track maintenance services and equipment
Disaggregation of Revenue [Line Items]
Total revenues	279,294	295,999	238,107
Harsco Rail | Operating segments | Air-cooled heat exchangers
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Industrial grating products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Heat transfer products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	205,212	196,567	191,726
Harsco Rail | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	48,016	78,698	30,270
Harsco Rail | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	3,977	2,827	2,014
Harsco Rail | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	22,089	17,907	13,025
Harsco Rail | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	1,072
Harsco Rail | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0