v3.26.1
Revenues - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Total contract assets $ 32,500 $ 32,500   $ 32,500   $ 69,100
Total advances on contracts 9,000 9,000   9,000   $ 8,200
Revenue recognized   1,400 $ 4,800 6,100 $ 22,400  
Contract exit charges $ 207,400 $ 40,500   $ 74,969 0  
SBB            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Percentage complete 92.00% 92.00%   92.00%    
(Decrease) to loss on contracts     4,800   5,900  
Network Rail            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Provisions recognized     10,200   11,300  
Deutsche Bahn            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
(Decrease) to loss on contracts     $ 0   $ (13,300)  
Harsco Environmental            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation $ 52,221 $ 52,221   $ 52,221    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 14,568 14,568   14,568    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 14,357 14,357   14,357    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 9,283 9,283   9,283    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 4,671 4,671   4,671    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 4,671 4,671   4,671    
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2032-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 4,671 4,671   4,671    
Harsco Rail            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 10,318 10,318   10,318    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 3,677 3,677   3,677    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 1,772 1,772   1,772    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 4,869 4,869   4,869    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 0 0   0    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation 0 0   0    
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2032-01-01            
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]            
Remaining performance obligation $ 0 $ 0   $ 0