Revenue Recognition - Summary of Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Total revenues	$ 2,240,358	$ 2,343,137	$ 2,366,187
Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	950,829	974,284	951,992
Applied Products [Member]
Disaggregation of Revenue [Line Items]
Total revenues	50,816	113,800	162,291
Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues	17,766	23,428	27,652
Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	83,882	113,039	128,155
After Market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	101,516	117,327	121,039
Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	61,696	60,922	47,601
Soil and dredged material
Disaggregation of Revenue [Line Items]
Total revenues	149,609	161,443	160,983
Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	824,244	778,894	766,474
North America
Disaggregation of Revenue [Line Items]
Total revenues	1,344,071	1,406,035	1,460,924
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	483,488	510,173	489,194
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	151,544	160,262	173,765
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	139,419	145,411	135,861
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	102,808	103,957	86,867
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	19,028	17,299	19,576
Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	2,240,358	2,343,137	2,366,187
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	1,019,411	1,111,512	1,141,935
Harsco Environmental | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	950,829	974,284	951,992
Harsco Environmental | Operating segments | Applied Products [Member]
Disaggregation of Revenue [Line Items]
Total revenues	50,816	113,800	162,291
Harsco Environmental | Operating segments | Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues	17,766	23,428	27,652
Harsco Environmental | Operating segments | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | After Market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | Soil and dredged material
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Environmental | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	228,691	292,274	318,574
Harsco Environmental | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	401,709	425,775	431,893
Harsco Environmental | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	148,619	154,684	171,225
Harsco Environmental | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	118,556	117,523	113,800
Harsco Environmental | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	102,808	103,957	86,867
Harsco Environmental | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	19,028	17,299	19,576
Clean Earth | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues	973,853	940,337	927,457
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 [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | After Market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Soil and dredged material
Disaggregation of Revenue [Line Items]
Total revenues	149,609	161,443	160,983
Clean Earth | Operating segments | Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	824,244	778,894	766,474
Clean Earth | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	973,853	940,337	927,457
Clean Earth | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Clean Earth | 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	247,094	291,288	296,795
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 [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	83,882	113,039	128,155
Harsco Rail | Operating segments | After Market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	101,516	117,327	121,039
Harsco Rail | Operating segments | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	61,696	60,922	47,601
Harsco Rail | Operating segments | Soil and dredged material
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Harsco Rail | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues	141,527	173,424	214,893
Harsco Rail | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	81,779	84,398	57,301
Harsco Rail | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	2,925	5,578	2,540
Harsco Rail | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	20,863	27,888	22,061
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