Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 382,251	$ 400,367
Changes to goodwill		259
Foreign currency translation	19,507	(18,375)
Balance at the end of the period	401,758	382,251
Harsco Metals & Minerals
Goodwill [Roll Forward]
Balance at the beginning of the period	362,386	380,761
Changes to goodwill		0
Foreign currency translation	19,507	(18,375)
Balance at the end of the period	381,893	362,386
Harsco Industrial
Goodwill [Roll Forward]
Balance at the beginning of the period	6,839	6,806
Changes to goodwill		33
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	12,800
Changes to goodwill		226
Foreign currency translation	0	0
Balance at the end of the period	$ 13,026	$ 13,026