Debt and Credit Agreements (Details 2)		1 Months Ended	12 Months Ended
	Dec. 02, 2015 USD ($)	Nov. 30, 2016	Dec. 31, 2021	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jan. 31, 2017 USD ($)	Dec. 01, 2015 USD ($)
Line of Credit Facility [Line Items]
Net sales proceeds						$ 145,000,000
Repayment of debt						979,567,000	$ 399,533,000	$ 131,007,000
Loss on early extinguishment of debt						(35,337,000)	0	0
Total debt obligations						673,410,000	880,835,000
Current maturities of long-term debt						25,574,000	25,084,000
Short-term borrowings						$ 4,259,000	$ 30,229,000
Weighted average interest rate						6.20%	4.30%
Interest paid						$ 49,600,000	$ 44,400,000	$ 44,200,000
Minimum consolidated interest coverage ratio, numerator						3.0
Minimum consolidated interest coverage ratio, denominator						1.0
Harsco Infrastructure | Infrastructure Transaction Strategic Venture
Line of Credit Facility [Line Items]
Percentage of ownership in equity method investments						26.00%	29.00%
Term Loan
Line of Credit Facility [Line Items]
Interest rate floor						1.00%
Quarterly payment, percentage of original principal amount						0.25%
Term Loan | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	375.00%
Term Loan | Minimum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	475.00%
Term Loan | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	400.00%
Term Loan | Maximum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	500.00%
Term Loan | Term Loan Facility 2015
Line of Credit Facility [Line Items]
Principle amount	$ 250,000,000
Repayment of debt						$ 85,000,000
Total debt obligations							$ 250,000,000
Term Loan | New Credit Facility
Line of Credit Facility [Line Items]
Principle amount						550,000,000
Term Loan | Term Loan Facility 2016
Line of Credit Facility [Line Items]
Total debt obligations						550,000,000
Secured Debt | Senior Secured Credit Facilities
Line of Credit Facility [Line Items]
Long-term and Short-term, combined amount						648,000,000	415,000,000
Total debt obligations						642,500,000	380,500,000
Current maturities of long-term debt						5,500,000	12,500,000
Short-term borrowings							22,000,000
Credit Agreement
Line of Credit Facility [Line Items]
Facility limit	$ 600,000,000					400,000,000	350,000,000			$ 500,000,000
Debt issuance cost						1,100,000
Minimum consolidated interest coverage ratio, numerator		4.0
Minimum consolidated interest coverage ratio, denominator		1.0
Revolving Credit Facility
Line of Credit Facility [Line Items]
Current borrowing capacity						$ 400,000,000
Consolidated net debt to consolidated adjusted EBITDA ratio						2.5
Long-term and Short-term, combined amount						$ 98,000,000	165,000,000
Total debt obligations						98,000,000	143,000,000
Short-term borrowings							$ 22,000,000
Revolving Credit Facility | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
Revolving Credit Facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.875%
Revolving Credit Facility | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.00%
Revolving Credit Facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.00%
Revolving Credit Facility | New Credit Facility
Line of Credit Facility [Line Items]
Repayment of debt						$ 60,000,000
Subsequent Event | Term Loan | Fixed-Rate Term Loan
Line of Credit Facility [Line Items]
Principle amount									$ 300,000,000
Forecast | Credit Agreement
Line of Credit Facility [Line Items]
Minimum consolidated interest coverage ratio, numerator				3.5	3.75
Forecast | Subsequent Event | Term Loan | Fixed-Rate Term Loan | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate			2.71%	1.65%