Information by Segment and Geographic Area (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,722,380	$ 1,607,062	$ 1,451,223
Operating income from continuing operations	190,927	145,394	64,883
Total assets	1,632,867	1,578,685	1,581,338	$ 1,542,754
Depreciation and Amortization	132,785	129,937	141,486
Capital Expenditures	132,168	98,314	69,340
Interest income	2,155	2,469	2,475
Interest expense	(38,148)	(47,552)	(51,584)
Defined benefit pension income (expense)	3,447	(2,595)	(1,414)
Loss on early extinguishment of debt	(1,127)	(2,265)	(35,337)
Change in fair value to unit adjustment liability	0	0	(58,494)
Income (loss) from continuing operations before income taxes and equity income	157,254	95,451	(79,471)
Operating segments
Segment Reporting Information [Line Items]
Operating income from continuing operations	213,201	170,847	85,802
Operating segments | Harsco Metals & Minerals
Segment Reporting Information [Line Items]
Revenues	1,068,304	1,011,328	965,540
Operating income from continuing operations	121,195	102,362	78,590
Total assets	1,230,152	1,184,280	1,181,602
Depreciation and Amortization	115,059	112,329	120,611
Capital Expenditures	114,142	87,526	62,322
Operating segments | Harsco Industrial
Segment Reporting Information [Line Items]
Revenues	374,708	299,592	247,542
Operating income from continuing operations	54,665	35,532	23,804
Total assets	163,324	113,410	107,987
Depreciation and Amortization	7,729	7,360	7,223
Capital Expenditures	7,561	6,895	5,118
Operating segments | Harsco Rail
Segment Reporting Information [Line Items]
Revenues	279,294	295,999	238,107
Operating income from continuing operations	37,341	32,953	(16,592)
Total assets	186,049	237,135	204,477
Depreciation and Amortization	4,287	4,221	5,383
Capital Expenditures	9,152	2,403	1,696
Corporate
Segment Reporting Information [Line Items]
Revenues	74	143	34
Operating income from continuing operations	(22,274)	(25,453)	(20,919)
Total assets	53,342	43,860	87,272
Depreciation and Amortization	5,710	6,027	8,269
Capital Expenditures	$ 1,313	$ 1,490	$ 204