Review of Operations by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operations by segment
Revenues	$ 528,855	$ 398,841
Operating income from continuing operations	24,824	2,881
Interest income	585	193
Interest expense	(16,864)	(12,649)
Unused debt commitment fees, amendment fees and loss on extinguishment of debt	(5,258)	(488)
Defined benefit pension income (expense)	(3,953)	(1,589)
Income (loss) from continuing operations before income taxes and equity income	7,240	(8,474)
Capital Expenditures	27,382	27,787
Depreciation	32,748	29,933
Amortization	8,967	6,557
Depreciation Excluding Industrial Segment		29,724
Operating Segments
Operations by segment
Operating income from continuing operations	33,777	21,237
Corporate
Operations by segment
Operating income from continuing operations	(8,953)	(18,356)
Capital Expenditures	68	58
Depreciation	483	513
Amortization	751	639
Harsco Environmental Segment | Operating Segments
Operations by segment
Revenues	257,986	241,559
Operating income from continuing operations	25,935	10,520
Capital Expenditures	24,419	24,748
Depreciation	25,717	25,375
Amortization	2,048	1,936
Harsco Clean Earth Segment | Operating Segments
Operations by segment
Revenues	189,279	78,812
Operating income from continuing operations	3,178	4,245
Capital Expenditures	2,530	1,442
Depreciation	5,337	2,621
Amortization	6,083	3,898
Harsco Rail Segment | Operating Segments
Operations by segment
Revenues	81,590	78,470
Operating income from continuing operations	4,664	6,472
Capital Expenditures	365	1,539
Depreciation	1,211	1,215
Amortization	$ 85	$ 84