CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020		Jun. 30, 2021	Jun. 30, 2020
Revenues from continuing operations:
Total revenues	$ 569,820	$ 447,281		$ 1,098,675	$ 846,122
Costs and expenses from continuing operations:
Selling, general and administrative expenses	82,665	80,771		165,708	153,270
Research and development expenses	628	792		1,446	2,052
Other (income) expenses, net	(4,063)	(292)		(4,975)	5,441
Total costs and expenses	533,601	445,413		1,037,632	841,373
Operating income from continuing operations	36,219	1,868		61,043	4,749
Interest income	638	816		1,223	1,009
Interest expense	(15,986)	(14,953)		(32,850)	(27,602)
Unused debt commitment fees, amendment fees and loss on extinguishment of debt	(50)	(1,432)		(5,308)	(1,920)
Defined benefit pension income	3,974	1,723		7,927	3,312
Income (loss) from continuing operations before income taxes and equity income	24,795	(11,978)		32,035	(20,452)
Income tax benefit (expense) from continuing operations	(8,564)	2,304		(12,793)	2,986
Equity income (loss) of unconsolidated entities, net	(76)	71		(195)	167
Income (loss) from continuing operations	16,155	(9,603)		19,047	(17,299)
Discontinued operations:
Gain (loss) on sale of discontinued business	0	(91)		0	18,371
Income (loss) from discontinued businesses	(1,451)	524		(3,242)	299
Income tax benefit (expense) from discontinued businesses	376	(285)		840	(9,599)
Income (loss) from discontinued operations, net of tax	(1,075)	148		(2,402)	9,071
Net income (loss)	15,080	(9,455)		16,645	(8,228)
Less: Net income attributable to noncontrolling interests	(1,692)	(1,147)		(3,122)	(2,233)
Net income (loss) attributable to Harsco Corporation	13,388	(10,602)		13,523	(10,461)
Amounts attributable to Harsco Corporation common stockholders:
Income (loss) from continuing operations, net of tax	14,463	(10,750)		15,925	(19,532)
Income (loss) from discontinued operations, net of tax	(1,075)	148		(2,402)	9,071
Net income (loss) attributable to Harsco Corporation	$ 13,388	$ (10,602)		$ 13,523	$ (10,461)
Weighted-average shares of common stock outstanding	79,265	78,987		79,177	78,874
Basic earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.18	$ (0.14)		$ 0.20	$ (0.25)
Discontinued operations (in dollars per share)	(0.01)	0		(0.03)	0.12
Basic earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ 0.17	$ (0.13)	[1]	$ 0.17	$ (0.13)
Diluted weighted-average shares of common stock outstanding (in shares)	80,774	78,987		80,397	78,874
Diluted earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.18	$ (0.14)		$ 0.20	$ (0.25)
Discontinued operations (in dollars per share)	(0.01)	0		(0.03)	0.12
Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ 0.17	$ (0.13)	[1]	$ 0.17	$ (0.13)
Products And Services, Service Revenue
Revenues from continuing operations:
Total revenues	$ 436,732	$ 345,643		$ 861,181	$ 637,232
Costs and expenses from continuing operations:
Cost of services sold	348,509	285,941		683,015	522,549
Product Revenues
Revenues from continuing operations:
Total revenues	133,088	101,638		237,494	208,890
Costs and expenses from continuing operations:
Cost of services sold	$ 105,862	$ 78,201		$ 192,438	$ 158,061

[1] Does not total due to rounding.