Acquisitions and Dispositions - Pro Forma Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Interest expense	$ 12,819	$ 5,620	$ 24,429	$ 16,891
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Pro forma revenues		422,700	1,236,200	1,215,500
Pro forma net income (including discontinued operations) (e)		32,000	477,500	77,000
Gain on disposition of business	$ 417,500		417,500
Acquisition-related Costs [Member] | Harsco Clean Earth Segment
Business Acquisition [Line Items]
Interest expense		$ 9,100	$ 18,200	$ 27,000