Revenue Recognition - Remaining Performance Obligation (Details) $ in Millions	Mar. 31, 2024 USD ($)
Harsco Environmental Segment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 82.2
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 21.8
Period of expected timing of satisfaction	1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 20.5
Period of expected timing of satisfaction	1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 15.0
Period of expected timing of satisfaction	1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 12.4
Period of expected timing of satisfaction	1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period of expected timing of satisfaction
Harsco Rail Segment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 140.7
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 53.4
Period of expected timing of satisfaction	1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 61.0
Period of expected timing of satisfaction	1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 22.6
Period of expected timing of satisfaction	1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 3.7
Period of expected timing of satisfaction	1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period of expected timing of satisfaction