Revenue Recognition - Summary of Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,503,742	$ 1,347,672	$ 1,307,470
Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	881,696	924,766	890,371
Applied Products [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	127,875	128,488	120,957
Aluminum Dross and Scrap Processing Systems [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	25,276	15,050	0
Railway Track Maintenance Equipment [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	145,968	112,547	146,267
After-market Parts and Services; Safety and Diagnostic Technology [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	132,249	139,020	110,195
Railway Contracting Services [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	21,156	27,727	39,537
Waste Processing and Reuse Solutions [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	169,522	0	0
General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	74	143
North America
Disaggregation of Revenue [Line Items]
Total revenues	685,613	507,524	471,186
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	431,162	438,856	448,461
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	148,628	155,863	161,957
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	159,441	167,850	156,218
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	60,402	50,003	42,700
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	18,496	27,576	26,948
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	74	143
Corporate | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Applied Products [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Aluminum Dross and Scrap Processing Systems [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Railway Track Maintenance Equipment [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | After-market Parts and Services; Safety and Diagnostic Technology [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Railway Contracting Services [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | Waste Processing and Reuse Solutions [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	74	143
Corporate | North America
Disaggregation of Revenue [Line Items]
Total revenues	0	74	143
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 Environmental | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	1,034,847	1,068,304	1,011,328
Harsco Environmental | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	881,696	924,766	890,371
Harsco Environmental | Operating segments | Applied Products [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	127,875	128,488	120,957
Harsco Environmental | Operating segments | Aluminum Dross and Scrap Processing Systems [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	25,276	15,050	0
Harsco Environmental | Operating segments | Railway Track Maintenance Equipment [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | After-market Parts and Services; Safety and Diagnostic Technology [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | Railway Contracting Services [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | Waste Processing and Reuse Solutions [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | General Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	294,367	302,238	274,476
Harsco Environmental | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	386,593	390,840	369,763
Harsco Environmental | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	146,040	151,886	159,130
Harsco Environmental | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	128,949	145,761	138,311
Harsco Environmental | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	60,402	50,003	42,700
Harsco Environmental | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	18,496	27,576	26,948
Clean Earth | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	169,522	0	0
Clean Earth | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Applied Products [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Aluminum Dross and Scrap Processing Systems [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Railway Track Maintenance Equipment [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | After-market Parts and Services; Safety and Diagnostic Technology [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Railway Contracting Services [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Waste Processing and Reuse Solutions [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	169,522	0	0
Clean Earth | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	169,522
Clean Earth | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0
Clean Earth | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0
Clean Earth | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0
Clean Earth | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0
Clean Earth | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0
Harsco Environmental | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Environmental | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues		0	0
Harsco Rail | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	299,373	279,294	295,999
Harsco Rail | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Applied Products [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Aluminum Dross and Scrap Processing Systems [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Railway Track Maintenance Equipment [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	145,968	112,547	146,267
Harsco Rail | Operating segments | After-market Parts and Services; Safety and Diagnostic Technology [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	132,249	139,020	110,195
Harsco Rail | Operating segments | Railway Contracting Services [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	21,156	27,727	39,537
Harsco Rail | Operating segments | Waste Processing and Reuse Solutions [Domain]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	221,724	205,212	196,567
Harsco Rail | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	44,569	48,016	78,698
Harsco Rail | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	2,588	3,977	2,827
Harsco Rail | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	30,492	22,089	17,907
Harsco Rail | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0