Review of Operations by Segment (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operations by segment
Total revenues	$ 445,475		$ 384,653	$ 1,285,485	$ 1,152,092
Operating income from continuing operations	57,109		34,629	147,275	106,385
Interest income	574		610	1,649	1,615
Interest expense	(9,665)		(12,122)	(29,241)	(36,180)
Defined benefit pension income (expense)	(928)		680	(2,671)	2,054
Loss on early extinguishment of debt	(125)	$ (1,000)	0	(1,159)	0
Income from continuing operations before income taxes	48,821		22,437	121,195	69,766
Depreciation and Amortization	33,373		33,005	99,944	97,508
Capital Expenditures	34,806		23,431	91,302	64,131
Operating Segments
Operations by segment
Operating income from continuing operations	62,297		40,958	162,854	124,722
Corporate
Operations by segment
Total revenues	0		38	74	107
Operating income from continuing operations	(5,188)		(6,329)	(15,579)	(18,337)
Depreciation and Amortization	1,332		1,449	4,346	4,399
Capital Expenditures	297		297	673	1,075
Harsco Metals & Minerals Segment | Operating Segments
Operations by segment
Total revenues	268,881		255,163	805,924	761,503
Operating income from continuing operations	29,338		23,613	92,734	80,834
Depreciation and Amortization	29,007		28,636	86,724	84,444
Capital Expenditures	29,870		20,994	79,469	58,065
Harsco Industrial Segment | Operating Segments
Operations by segment
Total revenues	93,912		78,318	269,575	217,766
Operating income from continuing operations	13,959		12,954	40,550	25,088
Depreciation and Amortization	1,971		1,826	5,708	5,509
Capital Expenditures	1,891		1,678	5,894	3,226
Harsco Rail Segment | Operating Segments
Operations by segment
Total revenues	82,682		51,134	209,912	172,716
Operating income from continuing operations	19,000		4,391	29,570	18,800
Depreciation and Amortization	1,063		1,094	3,166	3,156
Capital Expenditures	$ 2,748		$ 462	$ 5,266	$ 1,765