CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues from continuing operations:
Total revenues	$ 528,855	$ 398,841
Costs and expenses from continuing operations:
Selling, general and administrative expenses	83,043	72,499
Research and development expenses	818	1,260
Other (income) expenses, net	(912)	5,733
Total costs and expenses	504,031	395,960
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	3,953	1,589
Income (loss) from continuing operations before income taxes and equity income	7,240	(8,474)
Income tax benefit (expense) from continuing operations	(4,229)	682
Equity income (loss) of unconsolidated entities, net	(119)	96
Income (loss) from continuing operations	2,892	(7,696)
Discontinued operations:
Gain on sale of discontinued business	0	18,462
Loss from discontinued businesses	(1,791)	(225)
Income tax benefit (expense) from discontinued businesses	464	(9,314)
Income (loss) from discontinued operations, net of tax	(1,327)	8,923
Net income	1,565	1,227
Less: Net income attributable to noncontrolling interests	(1,430)	(1,086)
Net income attributable to Harsco Corporation	135	141
Amounts attributable to Harsco Corporation common stockholders:
Income (loss) from continuing operations, net of tax	1,462	(8,782)
Income (loss) from discontinued operations, net of tax	(1,327)	8,923
Net income attributable to Harsco Corporation	$ 135	$ 141
Weighted-average shares of common stock outstanding	79,088	78,761
Basic earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.02	$ (0.11)
Discontinued operations (in dollars per share)	(0.02)	0.11
Basic earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ 0	$ 0
Diluted weighted-average shares of common stock outstanding (in shares)	80,015	78,761
Diluted earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.02	$ (0.11)
Discontinued operations (in dollars per share)	(0.02)	0.11
Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ 0	$ 0
Products And Services, Service Revenue
Revenues from continuing operations:
Total revenues	$ 424,449	$ 291,589
Costs and expenses from continuing operations:
Cost of services sold	334,506	236,608
Product Revenues
Revenues from continuing operations:
Total revenues	104,406	107,252
Costs and expenses from continuing operations:
Cost of services sold	$ 86,576	$ 79,860