Dispositions - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Network Rail
Business Acquisition [Line Items]
Reversal of loss on contracts			$ 23.6
Revenue reduction				$ 24.5
Percentage complete	53.00%		53.00%
Deutsche Bahn
Business Acquisition [Line Items]
Contract estimated forward loss provision for Harsco Rail Segment	$ (2.4)		$ (10.8)	(7.4)
Percentage complete	42.00%		42.00%
SBB
Business Acquisition [Line Items]
Contract estimated forward loss provision for Harsco Rail Segment			$ (6.1)	(3.5)
SBB | Contract
Business Acquisition [Line Items]
Percentage complete	85.00%		85.00%
Discontinued Operations, Held-for-sale | Harsco Rail Segment
Business Acquisition [Line Items]
Corporate overhead expenses	$ 1.0	$ 1.0	$ 3.1	$ 3.1