Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 401,758	$ 382,251
Changes to goodwill	22,518
Foreign currency translation	(12,724)	19,507
Balance at the end of the period	411,552	401,758
Harsco Metals & Minerals
Goodwill [Roll Forward]
Balance at the beginning of the period	381,893	362,386
Changes to goodwill	22,518
Foreign currency translation	(12,724)	19,507
Balance at the end of the period	391,687	381,893
Harsco Industrial
Goodwill [Roll Forward]
Balance at the beginning of the period	6,839	6,839
Changes to goodwill	0
Foreign currency translation	0	0
Balance at the end of the period	6,839	6,839
Harsco Rail
Goodwill [Roll Forward]
Balance at the beginning of the period	13,026	13,026
Changes to goodwill	0
Foreign currency translation	0	0
Balance at the end of the period	$ 13,026	$ 13,026