Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 524,588	$ 486,914	$ 1,540,409	$ 1,420,763
Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Revenues	234,274	220,578	706,273	684,432
Ecoproducts
Disaggregation of Revenue [Line Items]
Revenues	43,841	40,274	122,747	110,322
Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Revenues	7,762	3,865	19,639	9,613
Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Revenues	194,927	182,558	578,545	512,382
Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Revenues	43,784	39,639	113,205	104,014
North America
Disaggregation of Revenue [Line Items]
Revenues	317,239	297,426	930,367	843,413
Western Europe
Disaggregation of Revenue [Line Items]
Revenues	109,473	92,757	318,177	294,427
Latin America
Disaggregation of Revenue [Line Items]
Revenues	44,351	40,574	127,486	115,581
Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenues	25,787	31,402	87,087	91,420
Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	22,673	20,195	62,195	60,843
Eastern Europe
Disaggregation of Revenue [Line Items]
Revenues	5,065	4,560	15,097	15,079
Operating Segments | Harsco Environmental Segment
Disaggregation of Revenue [Line Items]
Revenues	285,877	264,717	848,659	804,367
Operating Segments | Harsco Environmental Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Revenues	234,274	220,578	706,273	684,432
Operating Segments | Harsco Environmental Segment | Ecoproducts
Disaggregation of Revenue [Line Items]
Revenues	43,841	40,274	122,747	110,322
Operating Segments | Harsco Environmental Segment | Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Revenues	7,762	3,865	19,639	9,613
Operating Segments | Harsco Environmental Segment | Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | North America
Disaggregation of Revenue [Line Items]
Revenues	78,528	75,229	238,617	227,017
Operating Segments | Harsco Environmental Segment | Western Europe
Disaggregation of Revenue [Line Items]
Revenues	109,473	92,757	318,177	294,427
Operating Segments | Harsco Environmental Segment | Latin America
Disaggregation of Revenue [Line Items]
Revenues	44,351	40,574	127,486	115,581
Operating Segments | Harsco Environmental Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenues	25,787	31,402	87,087	91,420
Operating Segments | Harsco Environmental Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	22,673	20,195	62,195	60,843
Operating Segments | Harsco Environmental Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Revenues	5,065	4,560	15,097	15,079
Operating Segments | Clean Earth Segment
Disaggregation of Revenue [Line Items]
Revenues	238,711	222,197	691,750	616,396
Operating Segments | Clean Earth Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Ecoproducts
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Environmental systems for aluminum dross and scrap processing
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Hazardous waste processing solutions
Disaggregation of Revenue [Line Items]
Revenues	194,927	182,558	578,545	512,382
Operating Segments | Clean Earth Segment | Soil and dredged materials processing and reuse solutions
Disaggregation of Revenue [Line Items]
Revenues	43,784	39,639	113,205	104,014
Operating Segments | Clean Earth Segment | North America
Disaggregation of Revenue [Line Items]
Revenues	238,711	222,197	691,750	616,396
Operating Segments | Clean Earth Segment | Western Europe
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Latin America
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Operating Segments | Clean Earth Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 0	$ 0