Acquisitions and Dispositions - Acquisitions Narrative (Details) $ in Thousands, £ in Millions					1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 28, 2019 USD ($) facility	Jun. 28, 2019 USD ($) facility	Jun. 28, 2019 USD ($) facility TSDF_permits	Jun. 28, 2019 USD ($) facility RCRA_permits	May 31, 2018 GBP (£)	May 31, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	May 31, 2018 USD ($)
Business Acquisition [Line Items]
Total revenues							$ 350,898	$ 339,907	$ 680,800	$ 664,347
Additional interest expense							6,103	5,681	11,610	11,271
Purchase price									584,485	56,389
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Percentage of interests acquired	100.00%	100.00%	100.00%	100.00%
Enterprise valuation		$ 625,000
Cash consideration		628,000
Post-closing period	5 years
Estimated reimbursements	$ 8,000	$ 8,000	$ 8,000	$ 8,000
Number of permitted facilities | facility	27	27	27	27
Number Of Permits Acquired			6	9
Goodwill to be deductible for income tax purposes	$ 16,300	$ 16,300	$ 16,300	$ 16,300
Direct acquisition costs							12,000		12,500
Harsco Clean Earth Segment | Acquisition-related Borrowings
Business Acquisition [Line Items]
Additional interest expense							$ 9,200	$ 9,000	$ 18,200	$ 17,900
Harsco Clean Earth Segment | Scenario, Forecast
Business Acquisition [Line Items]
Total revenues											$ 300,000
Altek
Business Acquisition [Line Items]
Cash consideration						$ 57,400
Estimated reimbursements												$ 12,100
Purchase price					£ 45	$ 60,000
Additional contingent consideration					£ 25							$ 33,000