Information by Segment and Geographic Area (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) segment Customer	Dec. 31, 2018 USD ($) Customer	Dec. 31, 2017 USD ($) Customer
Revenue, Major Customer [Line Items]
Revenues | $	$ 1,503,742	$ 1,347,672	$ 1,307,470
Number of reportable segments | segment	3
Number of major customers	1	1,000	1,000
Harsco Environmental
Revenue, Major Customer [Line Items]
Number of major customers	1
Harsco Environmental
Revenue, Major Customer [Line Items]
Number of major customers		1	1
Clean Earth
Revenue, Major Customer [Line Items]
Number of major customers	0
Harsco Rail
Revenue, Major Customer [Line Items]
Number of major customers	1	1	1
All Other
Revenue, Major Customer [Line Items]
Revenues | $	$ 718,663	$ 745,943	$ 736,958
U.S. Plans
Revenue, Major Customer [Line Items]
Revenues | $	640,390	458,383	423,888
United Kingdom
Revenue, Major Customer [Line Items]
Revenues | $	$ 144,689	$ 143,346	$ 146,624