Review of Operations by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Operations by segment
Total revenues	$ 548,284	$ 600,317
Selling, general and administrative expenses	89,108	87,126
Remeasurement of long-lived assets	0	10,695
Other segment activities	4,485	(482)
Operating income (loss) from continuing operations	30,655	25,813
Interest income	454	1,697
Interest expense	(26,574)	(28,122)
Facility fees and debt-related income (expense)	(2,612)	(2,789)
Defined benefit pension income (expense)	(5,033)	(4,176)
Income (loss) from continuing operations before income taxes and equity in income	(3,110)	(7,577)
Depreciation	36,442	36,920
Amortization	7,403	8,174
Capital Expenditures	21,624	26,881
Service and Product
Operations by segment
Cost of services and products sold	424,036	477,165
Operating Segments
Operations by segment
Total revenues	548,284	600,317
Selling, general and administrative expenses	77,172	77,929
Remeasurement of long-lived assets		10,695
Other segment activities	6,183	3,408
Operating income (loss) from continuing operations	40,893	31,120
Depreciation	36,161	36,563
Amortization	6,452	7,207
Capital Expenditures	21,526	26,852
Operating Segments | Service and Product
Operations by segment
Cost of services and products sold	424,036	477,165
Operating Segments | Harsco Environmental Segment
Operations by segment
Total revenues	243,106	299,119
Selling, general and administrative expenses	26,628	28,902
Remeasurement of long-lived assets		0
Other segment activities	4,388	1,837
Operating income (loss) from continuing operations	10,073	19,588
Depreciation	25,509	28,789
Amortization	540	1,018
Capital Expenditures	14,094	20,553
Operating Segments | Harsco Environmental Segment | Service and Product
Operations by segment
Cost of services and products sold	202,017	248,792
Operating Segments | Clean Earth Segment
Operations by segment
Total revenues	235,231	226,030
Selling, general and administrative expenses	38,962	36,929
Remeasurement of long-lived assets		0
Other segment activities	(15)	60
Operating income (loss) from continuing operations	22,665	20,593
Depreciation	9,620	7,413
Amortization	5,845	6,167
Capital Expenditures	6,652	5,334
Operating Segments | Clean Earth Segment | Service and Product
Operations by segment
Cost of services and products sold	173,619	168,448
Operating Segments | Harsco Rail Segment
Operations by segment
Total revenues	69,947	75,168
Selling, general and administrative expenses	11,582	12,098
Remeasurement of long-lived assets		10,695
Other segment activities	1,810	1,511
Operating income (loss) from continuing operations	8,155	(9,061)
Depreciation	1,032	361
Amortization	67	22
Capital Expenditures	780	965
Operating Segments | Harsco Rail Segment | Service and Product
Operations by segment
Cost of services and products sold	48,400	59,925
Corporate
Operations by segment
Total revenues	0	0
Selling, general and administrative expenses	11,936	9,197
Remeasurement of long-lived assets		0
Other segment activities	(1,698)	(3,890)
Operating income (loss) from continuing operations	(10,238)	(5,307)
Depreciation	281	357
Amortization	951	967
Capital Expenditures	98	29
Corporate | Service and Product
Operations by segment
Cost of services and products sold	$ 0	$ 0