Enviri (NVRI) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-03970
Entity Registrant Name	HARSCO CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-1483991
Entity Address, Address Line One	350 Poplar Church Road,
Entity Address, City or Town	Camp Hill,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	17011
City Area Code	717
Local Phone Number	763-7064
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common stock, par value $1.25 per share
Trading Symbol	HSC
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		78,916,106
Entity Central Index Key	0000045876
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 83,859	$ 57,259
Restricted cash	2,283	2,473
Trade accounts receivable, net	400,994	309,990
Other receivables	38,325	21,265
Inventories	170,037	156,991
Current portion of contract assets	53,256	31,166
Current portion of assets held-for-sale	0	22,093
Other current assets	66,219	51,575
Total current assets	814,973	652,812
Property, plant and equipment, net	640,887	561,786
Right-of-use assets, net	96,800	52,065
Goodwill	881,911	738,369
Intangible assets, net	443,682	299,082
Deferred income tax assets	11,871	14,288
Assets held-for-sale	0	32,029
Other assets	55,365	17,036
Total assets	2,945,489	2,367,467
Current liabilities:
Short-term borrowings	10,246	3,647
Current maturities of long-term debt	2,753	2,666
Accounts payable	230,948	176,755
Accrued compensation	41,320	37,992
Income taxes payable	3,872	18,692
Insurance liabilities	11,589	10,140
Current portion of advances on contracts	42,763	53,906
Current portion of operating lease liabilities	26,577	12,544
Current portion of liabilities of assets held-for-sale	0	11,344
Other current liabilities	169,898	137,208
Total current liabilities	539,966	464,894
Long-term debt	1,246,395	775,498
Insurance liabilities	16,267	18,515
Retirement plan liabilities	151,230	189,954
Advances on contracts	43,273	6,408
Operating lease liabilities	67,995	36,974
Liabilities of assets held-for-sale	0	12,152
Environmental liabilities	29,747	5,600
Deferred tax liabilities	43,178	24,242
Other liabilities	41,024	43,571
Total liabilities	2,179,075	1,577,808
COMMITMENTS AND CONTINGENCIES
HARSCO CORPORATION STOCKHOLDERS' EQUITY
Preferred stock	0	0
Common stock	144,268	143,400
Additional paid-in capital	206,113	200,595
Accumulated other comprehensive loss	(597,052)	(587,622)
Retained earnings	1,804,061	1,824,100
Treasury stock	(843,098)	(838,893)
Total Harsco Corporation stockholders’ equity	714,292	741,580
Noncontrolling interests	52,122	48,079
Total equity	766,414	789,659
Total liabilities and equity	$ 2,945,489	$ 2,367,467

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Revenues from continuing operations:
Total revenues	$ 509,398	$ 423,155	$ 1,355,520		$ 1,103,955
Costs and expenses from continuing operations:
Selling, general and administrative expenses	87,954	63,197	241,224		187,104
Research and development expenses	568	1,341	2,620		3,210
Other expenses, net	3,633	383	9,074		409
Total costs and expenses	504,334	376,410	1,345,707		1,019,587
Operating income from continuing operations	5,064	46,745	9,813		84,368
Interest income	604	445	1,613		1,569
Interest expense	(15,794)	(12,819)	(43,396)		(24,429)
Unused debt commitment and amendment fees	0	(158)	(1,920)		(7,593)
Defined benefit pension income (expense)	1,859	(1,356)	5,171		(4,166)
Income (loss) from continuing operations before income taxes and equity income	(8,267)	32,857	(28,719)		49,749
Income tax benefit (expense)	1,654	(12,601)	4,640		(17,814)
Equity income of unconsolidated entities, net	9	81	176		151
Income (loss) from continuing operations	(6,604)	20,337	(23,903)		32,086
Discontinued operations:
Gain on sale of discontinued business	0	527,980	18,371		527,980
Income (loss) from discontinued businesses	(1,531)	272	(1,232)		23,958
Income tax expense related to discontinued businesses	(204)	(110,732)	(9,803)		(112,701)
Income (loss) from discontinued operations	(1,735)	417,520	7,336		439,237
Net income (loss)	(8,339)	437,857	(16,567)		471,323
Less: Net income attributable to noncontrolling interests	(1,239)	(2,506)	(3,472)		(6,633)
Net income (loss) attributable to Harsco Corporation	(9,578)	435,351	(20,039)		464,690
Amounts attributable to Harsco Corporation common stockholders:
Income (loss) from continuing operations, net of tax	(7,843)	17,831	(27,375)		25,453
Income (loss) from discontinued operations	(1,735)	417,520	7,336		439,237
Net income (loss) attributable to Harsco Corporation	$ (9,578)	$ 435,351	$ (20,039)		$ 464,690
Weighted-average shares of common stock outstanding	79,000	79,666	78,916		79,966
Basic earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ (0.10)	$ 0.22	$ (0.35)		$ 0.32
Discontinued operations (in dollars per share)	(0.02)	5.24	0.09		5.49
Basic earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ (0.12)	$ 5.46	$ (0.25)	[1]	$ 5.81
Diluted weighted-average shares of common stock outstanding (in shares)	79,000	81,110	78,916		81,749
Diluted earnings (loss) per common share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ (0.10)	$ 0.22	$ (0.35)		$ 0.31
Discontinued operations (in dollars per share)	(0.02)	5.15	0.09		5.37
Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ (0.12)	$ 5.37	$ (0.25)	[1]	$ 5.68
Products And Services, Service Revenue
Revenues from continuing operations:
Total revenues	$ 384,279	$ 316,667	$ 1,021,196		$ 784,190
Costs and expenses from continuing operations:
Cost of services sold	313,136	239,519	835,277		608,230
Product Revenues
Revenues from continuing operations:
Total revenues	125,119	106,488	334,324		319,765
Costs and expenses from continuing operations:
Cost of services sold	$ 99,043	$ 71,970	$ 257,512		$ 220,634
[1]	Does not total due to rounding

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (8,339)	$ 437,857	$ (16,567)	$ 471,323
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes	17,527	(22,780)	(35,244)	(22,276)
Net loss on cash flow hedging instruments, net of deferred income taxes	(263)	(314)	(1,622)	(4,485)
Pension liability adjustments, net of deferred income taxes	(9,153)	13,880	28,037	25,651
Unrealized gain (loss) on marketable securities, net of deferred income taxes	9	(6)	(22)	19
Total other comprehensive income (loss)	8,120	(9,220)	(8,851)	(1,091)
Total comprehensive income (loss)	(219)	428,637	(25,418)	470,232
Less: Comprehensive (income) loss attributable to noncontrolling interests	(2,795)	(821)	(4,053)	(4,768)
Comprehensive income (loss) attributable to Harsco Corporation	$ (3,014)	$ 427,816	$ (29,471)	$ 465,464

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, deferred income taxes	$ 2,418	$ (1,834)	$ (2,323)	$ (2,086)
Net gain (loss) on cash flow hedging instruments, deferred income taxes	(125)	54	141	1,195
Pension liability adjustments, deferred income taxes	(323)	(340)	(2,356)	(1,061)
Unrealized gain (loss) on marketable securities, deferred income taxes	$ (4)	$ 2	$ 8	$ (6)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ (16,567)	$ 471,323
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	93,864	89,681
Amortization	24,721	11,941
Deferred income tax expense	2,346	11,500
Equity income of unconsolidated entities, net	(176)	(151)
Dividends from unconsolidated entities	0	125
Gain on sale from discontinued business	(18,371)	(527,980)
Loss on early extinguishment of debt	0	5,314
Other, net	(336)	2,187
Changes in assets and liabilities, net of acquisitions and dispositions of businesses:
Accounts receivable	26,308	(12,395)
Increase (Decrease) in Income Taxes Receivable	(11,168)	0
Inventories	(11,801)	(43,477)
Contract assets	(26,775)	(5,269)
Right-of-use assets	18,195	11,204
Accounts payable	(1,488)	5,615
Accrued interest payable	(9,984)	7,398
Accrued compensation	1,795	(12,802)
Advances on contracts	19,145	(17,067)
Operating lease liabilities	(17,864)	(10,919)
Retirement plan liabilities, net	(23,902)	(18,800)
Income taxes payable - Gain on sale of discontinued businesses	(10,342)	102,940
Other assets and liabilities	4,676	(20,339)
Net cash provided by operating activities	42,276	50,029
Cash flows from investing activities:
Purchases of property, plant and equipment	(79,096)	(147,071)
Purchases of businesses, net of cash acquired	(432,855)	(623,495)
Proceeds from Divestiture of Businesses	37,219	599,685
Proceeds from sales of assets	4,473	7,560
Expenditures for intangible assets	(169)	(1,246)
Net proceeds from settlement of foreign currency forward exchange contracts	536	1,453
Payments for interest rate swap terminations	0	(2,758)
Other investing activities, net	(197)	0
Net cash used by investing activities	(470,089)	(165,872)
Cash flows from financing activities:
Short-term borrowings, net	1,712	(1,417)
Current maturities and long-term debt:
Additions	580,903	781,987
Reductions	(111,999)	(604,616)
Dividends paid to noncontrolling interests	0	(3,103)
Sale of noncontrolling interests	0	4,026
Common stock acquired for treasury	0	(25,752)
Stock-based compensation - Employee taxes paid	(4,188)	(11,202)
Payment of contingent consideration	(2,342)	0
Deferred financing costs	(1,928)	(11,073)
Other financing activities, net	(1,368)	0
Net cash provided by financing activities	460,790	128,850
Effect of exchange rate changes on cash and cash equivalents, including restricted cash	(6,567)	(2,234)
Net increase in cash and cash equivalents, including restricted cash	26,410	10,773
Cash and cash equivalents, including restricted cash, at beginning of period	59,732	67,146
Cash and cash equivalents, including restricted cash, at end of period	86,142	77,919
Change in accrual for purchases of property, plant and equipment included in accounts payable	$ 3,060	$ 5,917

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock Issued	Common Stock Treasury	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance at Dec. 31, 2018	$ 313,376	$ 141,842	$ (795,821)	$ 190,597	$ 1,298,752	$ (567,107)	$ 45,113
Increase (Decrease) in Stockholders' Equity
Net income (loss)	22,537				20,697		1,840
Sale of subsidiary shares to noncontrolling interest	876						876
Total other comprehensive income	4,531					4,111	420
Stock appreciation rights exercised, net	(8)	2	(8)	(2)
Vesting of restricted stock units and other stock grants, net	(1,456)	198	(1,456)	(198)
Vesting of performance share units, net	(8,248)	1,136	(8,235)	(1,149)
Amortization of unearned portion of stock-based compensation, net of forfeitures	3,664			3,664
Ending balance at Mar. 31, 2019	335,272	143,178	(805,520)	192,912	1,340,878	(584,425)	48,249
Beginning balance at Dec. 31, 2018	313,376	141,842	(795,821)	190,597	1,298,752	(567,107)	45,113
Increase (Decrease) in Stockholders' Equity
Net income (loss)	471,323
Total other comprehensive income	(1,091)
Ending balance at Sep. 30, 2019	751,260	143,396	(832,775)	198,007	1,784,871	(587,759)	45,520
Beginning balance at Mar. 31, 2019	335,272	143,178	(805,520)	192,912	1,340,878	(584,425)	48,249
Increase (Decrease) in Stockholders' Equity
Net income (loss)	10,929				8,642		2,287
Total other comprehensive income	3,598					4,196	(598)
Stock appreciation rights exercised, net	(108)	18	(108)	(18)
Vesting of performance share units, net	(1,375)	198	(1,375)	(198)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,338			2,338
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	4,690						4,690
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	3,150						3,150
Ending balance at Jun. 30, 2019	349,114	143,394	(807,003)	195,034	1,349,520	(580,229)	48,398
Increase (Decrease) in Stockholders' Equity
Net income (loss)	437,857				435,351		2,506
Total other comprehensive income	(9,220)					(7,530)	(1,690)
Strategic venture exit	(3,694)						(3,694)
Stock appreciation rights exercised, net	(1)		(1)
Vesting of restricted stock units and other stock grants, net	(19)	2	(19)	(2)
Treasury shares repurchased	(25,752)		(25,752)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,975			2,975
Ending balance at Sep. 30, 2019	751,260	143,396	(832,775)	198,007	1,784,871	(587,759)	45,520
Beginning balance at Dec. 31, 2019	789,659	143,400	(838,893)	200,595	1,824,100	(587,622)	48,079
Increase (Decrease) in Stockholders' Equity
Net income (loss)	1,227				141		1,086
Total other comprehensive income	(30,002)					(28,854)	(1,148)
Vesting of restricted stock units and other stock grants, net	(889)	230	(889)	(230)
Vesting of performance share units, net	(3,205)	589	(3,205)	(589)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,080			2,080
Ending balance at Mar. 31, 2020	758,870	144,219	(842,987)	201,856	1,824,241	(616,476)	48,017
Beginning balance at Dec. 31, 2019	789,659	143,400	(838,893)	200,595	1,824,100	(587,622)	48,079
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(16,567)
Total other comprehensive income	(8,851)
Ending balance at Sep. 30, 2020	766,414	144,268	(843,098)	206,113	1,804,061	(597,052)	52,122
Beginning balance at Mar. 31, 2020	758,870	144,219	(842,987)	201,856	1,824,241	(616,476)	48,017
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(9,455)				(10,602)		1,147
Total other comprehensive income	13,031					12,858	173
Stock appreciation rights exercised, net	(16)	8	(16)	(8)
Vesting of restricted stock units and other stock grants, net	0	18		(18)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,086			2,086
Ending balance at Jun. 30, 2020	764,516	144,245	(843,003)	203,916	1,813,639	(603,618)	49,337
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(8,339)				(9,578)		1,239
Total other comprehensive income	8,120					6,566	1,554
Stock appreciation rights exercised, net	(8)	3	(8)	(3)
Vesting of restricted stock units and other stock grants, net	(87)	20	(87)	(20)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,220			2,220
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	8						8
Ending balance at Sep. 30, 2020	$ 766,414	$ 144,268	$ (843,098)	$ 206,113	$ 1,804,061	$ (597,052)	$ 52,122

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Total other comprehensive income, deferred income taxes	$ 1,966	$ (1,229)	$ (5,267)	$ (2,118)	$ (1,569)	$ 1,729
Stock appreciation rights exercised (in shares)	1,609	6,744		103	10,216	927
Vesting of restricted stock units and other stock grants (in shares)	10,910	14,211	104,840	984	99,134	94,229
Treasury shares repurchased (in shares)				1,417,556
Stock Issued During Period, Shares, Other			265,151			529,213

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared these unaudited condensed consolidated financial statements in accordance with U.S. GAAP for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the SEC. Accordingly, the unaudited condensed consolidated financial statements do not include all information and disclosure required by U.S. GAAP for annual financial statements. The December 31, 2019 Condensed Consolidated Balance Sheet information contained in this Quarterly Report on Form 10-Q was derived from the 2019 audited consolidated financial statements. The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements, including the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. In the opinion of management, all adjustments (all of which are of a normal recurring nature) that are necessary for a fair statement are reflected in the unaudited condensed consolidated financial statements. Restricted Cash The Company had restricted cash of $2.3 million and $2.5 million at September 30, 2020 and December 31, 2019, respectively, and the restrictions are primarily related to collateral provided for certain guarantees of the Company's performance. Acquisition of ESOL On April 6, 2020 the Company completed the previously announced acquisition of ESOL, an established waste transportation, processing and services provider with a comprehensive portfolio of disposal solutions for customers primarily across the industrial, retail and healthcare markets, from Stericycle, Inc. for $429.0 million in cash, inclusive of post-closing adjustments. See Note 3, Acquisitions and Dispositions, for additional information. Segment Reporting The Company reports information about operating segments using the "management approach," which is based on the way management organizes and reports the segments within the enterprise for making operating decisions and assessing performance. The Company's reportable segments are identified based upon differences in products, service and markets served. The operations of ESOL are combined and included as part of the Harsco Clean Earth Segment. Impact of COVID-19 Beginning in early 2020, overall global economic conditions were significantly impacted by COVID-19. The continuing impact of COVID-19 on the Company varies by end market as well as local conditions (including applicable government mandates) and is continually evolving. The ultimate duration and impact of COVID-19 on the Company and its customers' operations is presently unclear, though the Company continues to operate as a provider of certain essential services in the U.S. and other countries. The Company continues to take significant and proactive actions to protect all stakeholders and to minimize the operational and financial impacts of COVID-19 where possible. The Company did not record any long-lived asset impairments, indefinite-lived asset impairments, goodwill impairments, significant inventory write-downs or incremental accounts receivable reserves for current expected credit losses during the three months or nine months ended September 30, 2020, however such charges are possible in future periods, which could have an adverse effect on the Company's future results of operations, cash flows, or financial condition. Discontinued Operations In January 2020 the Company sold IKG and, together with the 2019 sales of AXC and PK, this completed the divestiture of the former Harsco Industrial Segment originally announced in May 2019. These disposals represent a strategic shift and accelerated the transformation of the Company's portfolio of businesses into a leading provider of environmental solutions and services. As a result of these disposals (i) the carrying value of the remaining assets and liabilities of the Harsco Industrial Segment were classified as Assets held-for-sale and Liabilities of assets held-for-sale on the Company's December 31, 2019 Condensed Consolidated Balance Sheet; (ii) the operating results of the Harsco Industrial Segment, costs directly related to the disposals, an allocation of interest expense associated with mandatory debt repayments required as a result of the disposals and the write-off of deferred financing costs resulting from the mandatory repayment have been reflected in the Company's Condensed Consolidated Statements of Operations as discontinued operations for all periods presented; and (iii) all disclosures have been updated to reflect these changes. See Note 3, Acquisitions and Dispositions, for additional information. Reclassifications Certain reclassifications have been made to prior year amounts to conform with current year classifications.

Recently Adopted and Recently I

Recently Adopted and Recently Issued Accounting Standards	9 Months Ended
	Sep. 30, 2020
Accounting Changes and Error Corrections [Abstract]
Recently Adopted and Recently Issued Accounting Standards	Recently Adopted and Recently Issued Accounting Standards The following accounting standards have been adopted in 2020: On January 1, 2020 the Company adopted changes issued by the FASB which updated the impairment model for credit losses by requiring entities to use a forward-looking approach based on expected losses rather than incurred losses to estimate credit losses on certain types of financial instruments, including trade receivables. Provisions for receivables will be recorded as Allowance for expected credit losses, replacing the previously utilized Allowance for doubtful accounts. In addition, these changes required certain expanded disclosures. Other than changes in disclosure, these changes did not have a material impact on the Company's condensed consolidated financial statements as the calculation of expected credit losses did not yield results that were materially different from the methodology previously utilized by the Company. See Note 4, Accounts Receivable and Note Receivable for additional information. On January 1, 2020 the Company adopted changes issued by the FASB that removed the second step of the annual goodwill impairment test, which required a hypothetical purchase price allocation. The changes provide that the amount of goodwill impairment will be equal to the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. All other goodwill impairment guidance remains largely unchanged. The same one-step impairment test will be applied to goodwill at all reporting units, even those with zero or negative carrying amounts. Entities will be required to disclose the amount of goodwill at reporting units with zero or negative carrying amounts. These changes did not have a material impact on the Company's condensed consolidated financial statements. On January 1, 2020 the Company adopted changes issued by the FASB which modified the disclosure requirements for fair value measurements. The amendments in this update remove the requirement to disclose the amount of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy; and the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. The changes require disclosure of changes in unrealized gains and losses for the period included in OCI for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Other than required expanded disclosures, the adoption of these changes did not have a material impact on the Company's condensed consolidated financial statements. The following accounting standards have been issued and become effective for the Company at a future date: In December 2019 the FASB issued changes which are intended to reduce complexity and simplify the accounting for income taxes in accordance with U.S. GAAP by removing certain exceptions related to investments, intraperiod allocations and interim calculations and clarifying existing guidance to improve consistent application. The changes become effective for the Company on January 1, 2021. Management does not believe these changes will have a material impact on its condensed consolidated financial statements. In March 2020 the FASB issued changes that provide companies with optional guidance to ease the potential accounting burden associated with transitioning from reference rates that are expected to be discontinued. In response to the concerns about risks of IBORs and, particularly, the risk of cessation of LIBOR, regulators in several jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction-based and less susceptible to manipulation. The changes provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The changes can be adopted no later than December 31, 2022 with early adoption permitted. Management does not believe these changes will have a material impact on its condensed consolidated financial statements. In August 2020, the FASB issued changes which simplified the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. Management concluded that this standard will not have an impact on its condensed consolidated financial statements.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions ESOL On April 6, 2020 the Company completed the previously announced acquisition of 100% of ESOL, an established waste transportation, processing and services provider with a comprehensive portfolio of disposal solutions for customers primarily across the industrial, retail and healthcare markets from Stericycle, Inc. for $429.0 million of cash consideration, inclusive of post-closing adjustments. In addition, as part of the acquisition, the Company entered into a non-compete agreement with Stericycle, Inc. Concurrent to the ESOL acquisition, the Company entered into an agreement with Stericycle Inc. related to certain Stericycle, Inc. customers who receive services from both ESOL and other Stericycle, Inc. businesses under a single contractual arrangement. The revenue pertaining to services rendered to these customers are invoiced centrally through Stericycle, Inc. billing systems and ESOL's portion of the revenue, less a management fee, is then distributed to the Company. The preliminary fair value recorded for the assets acquired and liabilities assumed for ESOL is as follows: Preliminary Valuation (In millions) April 6 Measurement Period Adjustments September 30 Cash and cash equivalents $ 0.4 $ — $ 0.4 Trade accounts receivable 124.1 (0.9) 123.2 Inventory 5.0 — 5.0 Other current assets 0.7 (0.4) 0.3 Property, plant and equipment 105.3 — 105.3 Right-of-use assets 56.0 — 56.0 Goodwill 152.0 (8.1) 143.9 Intangible assets 161.0 — 161.0 Other assets 0.2 — 0.2 Accounts payable (48.6) (0.4) (49.0) Accrued expenses (17.5) — (17.5) Current portion of operating lease liabilities (16.6) — (16.6) Other current liabilities (6.4) — (6.4) Environmental liabilities (24.4) — (24.4) Deferred income taxes (15.5) — (15.5) Operating lease liabilities (39.4) — (39.4) Total identifiable net assets of ESOL 436.3 (9.8) 426.5 Non-compete agreement 2.5 — 2.5 Total identifiable net assets of ESOL, including non-compete agreement $ 438.8 $ (9.8) $ 429.0 The goodwill is primarily attributed to expected operational efficiencies and synergies from the expanded geographical scale of hazardous waste processing facilities resulting from combining the ESOL business with the existing Clean Earth business of the Company, as well as the value associated with the assembled workforce of ESOL. The Company expects $36.8 million of goodwill to be deductible for income tax purposes through 2030. The following table details the preliminary valuation of identifiable intangible assets and amortization periods for ESOL and the non-compete agreement entered into by the Company upon acquisition of ESOL: Preliminary Valuation (Dollars in millions) Weighted-Average Amortization Period April 6 Measurement Period Adjustments September 30 Permits and rights 22 years $ 138.0 $ — $ 138.0 Customer relationships 10 years 23.0 — 23.0 Total identifiable intangible assets of ESOL 161.0 — 161.0 Non-compete agreement 4 years 2.5 — 2.5 Total identifiable intangible assets acquired $ 163.5 $ — $ 163.5 The Company valued the identifiable intangible assets using methodologies under the income approach including the multi-period excess earnings method, the distributor method, and the with-and-without method. The purchase price allocation for ESOL is not final and the fair value of intangible assets and goodwill may vary significantly from those reflected in the Company's condensed consolidated financial statements at September 30, 2020. ESOL contributed revenue of $236.7 million and operating income of $4.7 million for the nine months ended September 30, 2020. The operations of ESOL have been combined and included as part of the Harsco Clean Earth Segment. The three and nine months September 30, 2020 include ESOL direct acquisition and integration costs of $10.6 million and $41.0 million, respectively, which are included in the Selling, general and administrative expenses, within the Corporate function, in the Company's Condensed Consolidated Statements of Operations. In addition to the acquisition and integration costs reflected in the Company's Condensed Consolidated Statements of Operations, the debt issuance costs associated with the issuance of debt to fund the acquisition are reflected, net of amortization subsequent to the acquisition date, as Long-term debt on the Company's Condensed Consolidated Balance Sheets. Clean Earth On June 28, 2019 the Company acquired 100% of the outstanding stock of Clean Earth, one of the largest U.S. providers of specialty waste processing and beneficial reuse solutions for hazardous waste, contaminated materials and dredged volumes, for an enterprise valuation of approximately $625 million on a cash free, debt free basis, subject to normal working capital adjustments. The Company transferred approximately $628 million of cash consideration and agreed to reimburse the sellers for any usage of assumed net operating losses in a post-closing period for up to five years. During the three months ended September 30, 2020, the Company expensed an additional $2.4 million related to the expected reimbursement of these net operating losses of which the present value is now estimated at approximately $11 million. See Footnote 17, Other Expenses, net, for additional details. The fair value recorded for the assets acquired and liabilities assumed for Clean Earth is as follows: Final (In millions) Measurement Period Adjustments (a) September 30 Cash and cash equivalents (b) $ 42.8 $ (39.2) $ 3.6 Trade accounts receivable, net 63.7 (1.2) 62.5 Other receivables 0.8 1.3 2.1 Other current assets 8.7 (1.4) 7.3 Property, plant and equipment 75.6 1.4 77.0 Right-of-use assets 14.4 11.4 25.8 Goodwill 313.8 16.8 330.6 Intangible assets 261.1 (18.9) 242.2 Other assets 4.0 (2.8) 1.2 Accounts payable (23.0) (0.1) (23.1) Acquisition consideration payable (b) (39.2) 39.2 — Other current liabilities (18.0) (1.7) (19.7) Net deferred taxes liabilities (51.2) 5.5 (45.7) Operating lease liabilities (11.1) (8.4) (19.5) Other liabilities (6.5) (2.1) (8.6) Total identifiable net assets of Clean Earth $ 635.9 $ (0.2) $ 635.7 (a) The measurement period adjustments did not have a material impact on the Company's previously reported operating results. (b) Acquisition consideration payable represents a portion of the cash consideration not paid out until July 2019. The goodwill is attributable to strategic benefits, including enhanced operational and financial scale, as well as product and market diversification that the Company expects to realize. The Company expects $16.3 million of goodwill to be deductible for income tax purposes through 2033. The following table details the valuation of identifiable intangible assets and amortization periods for Clean Earth: Final (In millions) Weighted-Average Amortization Period Preliminary Measurement Period Adjustments (c) September 30 Permits 18 years $ 176.1 $ (6.0) $ 170.1 Customer relationships 8 years 33.4 (12.9) 20.5 Air rights Usage based (d) 25.6 — 25.6 Trade names 12 years 26.0 — 26.0 Total identifiable intangible assets of Clean Earth $ 261.1 $ (18.9) $ 242.2 (c) The measurement period adjustments did not have a material impact on the Company's previously reported operating results. (d) The Company estimates that based on current usage that the expected useful life would be 27 years. The Company valued the identifiable intangible assets using an income-based approach that utilized either the multi-period excess earnings method or the relief from royalty method. The three and nine months ended September 30, 2019 include Clean Earth direct acquisition and integration costs of $2.0 million and $14.5 million, respectively which are included in Selling, general and administrative expenses, within the Corporate function, in the Company’s Condensed Consolidated Statements of Operations. Pro forma financial information The pro forma information below gives effect to the Clean Earth acquisition as if it had been completed on January 1, 2018 and the ESOL acquisition as if it had been completed on January 1, 2019. The pro forma information is not necessarily indicative of the Company’s results of operations had the acquisitions been completed on the above dates, nor is it necessarily indicative of future results. The pro forma information does not reflect any cost savings from operating efficiencies or synergies that could result from the acquisitions and does not reflect the additional revenue opportunities following the acquisitions. The pro forma information below includes the adjustments necessary to reflect additional depreciation and amortization expense based on the estimated fair value and useful lives of intangible assets and fixed assets acquired; includes additional interest expense of approximately $4.7 million for the nine months ended September 30, 2020 and $5.6 million and $34.9 million for the three and nine months ended September 30, 2019, respectively, on the acquisition related borrowings used to finance the acquisitions and excludes certain directly attributable acquisition and integration costs and historic interest expense. These pro forma adjustments are subject to change as additional analysis is performed. The values assigned to the assets acquired and liabilities assumed are based on preliminary valuations, for the ESOL acquisition, and are subject to change as the Company obtains additional information during the remaining measurement period. In addition, the historical ESOL results include $8.9 million for the nine months ended September 30, 2020 and $8.6 million and $26.5 million for the three and nine months ended September 30, 2019, respectively, of corporate expenses charged to ESOL from Stericycle. Three Months Ended Nine Months Ended September 30 September 30 (In millions) 2020 2019 2020 2019 Pro forma revenues $ 509.4 $ 572.7 $ 1,486.2 $ 1,650.3 Pro forma net income attributed to Harsco Corporation (including discontinued operations) (e) (1.8) 434.9 1.0 440.9 (e) Pro forma net income for the three and nine months ended September 30, 2019 includes a $417.5 million after-tax gain on the sale of AXC. Harsco Industrial Segment In January 2020 the Company sold IKG for $85.0 million, including a note receivable with a face value of $40.0 million (initial fair value $34.3 million), and recognized an $18.4 million pre-tax gain on sale (or approximately $9 million after-tax). This disposal, along with the disposals of AXC and PK in 2019, represent a strategic shift and accelerates the transformation of the Company's portfolio of businesses into a global, market-leading, single-thesis environmental solutions platform. See Note 4, Accounts Receivable and Note Receivable, for additional information related to the note receivable. The Harsco Industrial Segment has historically been a separate reportable segment with primary operations in North America and Latin America. In accordance with U.S. GAAP, the results of the former Harsco Industrial Segment are presented as discontinued operations and, as such, have been excluded from both continuing operations and segment results for the three and nine months ended September 30, 2020 and 2019. Certain key selected financial information included in net income (loss) from discontinued operations for the former Harsco Industrial Segment is as follows: Three Months Ended Nine Months Ended September 30 September 30 (In millions) 2020 2019 2020 2019 Amounts for the former Harsco Industrial Segment: Total revenues $ — $ 39,855 $ 10,203 $ 274,037 Cost of products sold — 28,174 8,082 201,188 Gain on sale from discontinued business — 527,980 18,371 527,980 Income (loss) from discontinued business (716) 803 (593) 24,877 Additional amounts allocated to the former Harsco Industrial Segment: Selling, general and administrative expenses (f) $ 521 $ 1,994 $ 1,710 $ 5,521 Interest expense (g) — — — 11,237 Loss on early extinguishment of debt (h) — 5,314 — 5,314 (f) The Company has allocated directly attributable transaction costs to discontinued operations. In addition, this caption includes costs directly attributable to retained contingent liabilities of the Harsco Industrial Segment. (g) The Company has allocated interest expense, including a portion of the amount reclassified into income for the Company's interest rate swaps and amortization of deferred financing costs resulting from the AXC disposal, as part of discontinued operations. (h) The Company has allocated the $5.3 million write-off of deferred financing costs to discontinued operations as it is directly attributable to the mandatory repayment of the Original Term Loan that resulted from the AXC disposal. The Company has retained corporate overhead expenses previously allocated to the Harsco Industrial Segment of $0.7 million for the three months ended September 30, 2019 and $3.4 million for the nine months ended September 30, 2019, as part of Selling, general and administrative expenses, on the Company's Condensed Consolidated Statements of Operations. The following is selected financial information included on the Company's Condensed Consolidated Statements of Cash Flows attributable to the former Harsco Industrial Segment: Nine Months Ended September 30 (In millions) 2020 2019 Non-cash operating items Depreciation and amortization $ — $ 3,301 Cash flows from investing activities Purchases of property, plant and equipment 106 6,151

Accounts Receivable (Notes)

Accounts Receivable (Notes)	9 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Accounts and Nontrade Receivable [Text Block]	Accounts Receivable and Note Receivable Accounts receivable are stated at net realizable value which represents the face value of the receivable less an allowance for expected credit losses. The allowance for expected credit losses is maintained for expected lifetime losses resulting from the inability or unwillingness of customers to make required payments. The Company’s expected credit loss allowance methodology for accounts receivable is developed using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. When required, the Company adjusts the loss-rate methodology to account for current conditions and reasonable and supportable expectations of future economic and market conditions. The Company generally assesses future economic conditions for a period which corresponds with the contractual life of its accounts receivable. Additionally, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Prior to the adoption of the expected credit loss allowance methodology on January 1, 2020, the Company established an allowance for doubtful accounts based upon a specific-identification method as well as historical collection experience, as appropriate. Accounts receivable consist of the following: (In thousands) September 30 December 31 Trade accounts receivable $ 409,928 $ 323,502 Less: Allowance for expected credit losses and doubtful accounts (a) (b) (8,934) (13,512) Trade accounts receivable, net $ 400,994 $ 309,990 Other receivables (c) $ 38,325 $ 21,265 (a) The decrease in the allowance for expected credit losses and doubtful accounts is the final write-off of previously fully-reserved balances in the Harsco Environmental Segment. (b) Upon the acquisition of ESOL, trade accounts receivable totaling $136.2 million were recorded at a fair value of $123.2 million as of the acquisition date, due primarily to expected credit losses as of the acquisition date of $13.0 million which were netted against the gross receivable balance as of the acquisition date. (c) Other receivables include employee receivables, insurance receivable, tax claims and refunds and other miscellaneous items not included in Trade accounts receivable, net. The change in the provision for expected credit losses and doubtful accounts related to trade accounts receivable was as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Provision for expected credit losses and doubtful accounts related to trade accounts receivable $ 861 $ 1,116 $ 1,098 $ 6,539 At September 30, 2020 approximately $5.6 million of the Company's trade accounts receivable were past due by twelve months or more. Approximately $1.1 million of this amount is reserved, and collection of the remaining balance is still ultimately expected. In January 2020 the Company sold IKG for $85.0 million including cash and a note receivable, subject to post-closing adjustments. The note receivable from the buyer has a face value of $40.0 million, bearing interest at 2.50%, that is paid in kind and matures on January 31, 2027. Any unpaid principal, along with any accrued but unpaid interest is payable at maturity. Prepayment is required in case of a change in control or a percentage of excess cash flow, as defined in the note receivable agreement. Because there are no scheduled payments under the terms of the note receivable, the balance is not classified as current as of September 30, 2020 and is included in the caption Other assets on the Condensed Consolidated Balance Sheet. The initial fair value of the note receivable was $34.3 million which was calculated using an average of various discounted cash flow scenarios based on anticipated timing of repayments (Level 3) and was a non-cash transaction. The note receivable is subsequently measured at amortized cost. Key inputs into the valuation model include: projected timing and amount of cash flows, pro forma debt rating, option-adjusted spread and U.S. Treasury spot rate. At September 30, 2020 the amortized cost of the note receivable was $35.4 million, compared with a fair value of $35.6 million. (In thousands) September 30 December 31 Note receivable $ 35,389 $ —

Inventories

Inventories	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: (In thousands) September 30 December 31 Finished goods $ 14,736 $ 14,550 Work-in-process 13,489 13,088 Raw materials and purchased parts 111,754 104,488 Stores and supplies 30,058 24,865 Total inventories $ 170,037 $ 156,991 During 2016 the Company recognized an initial estimated forward loss provision related to the contracts with SBB of $45.1 million. The Company recorded an additional forward loss provision of $1.8 million during 2018. At September 30, 2020 the entire remaining estimated forward loss provision of $6.6 million is included as Other current liabilities on the Company's Condensed Consolidated Balance Sheets. The estimated forward loss provision represents the Company's best estimate based on currently available information. It is possible that the Company's overall estimate of costs to complete these contracts may increase, which would result in an additional estimated forward loss provision at such time. The Company recognized $11.8 million and $5.7 million of revenues for the contracts with SBB at zero margin, on an over time basis, utilizing a cost-to-cost method for the three months ended September 30, 2020 and 2019, respectively, and $29.5 million and $16.4 million for the nine months ended September 30, 2020 and 2019, respectively. Consolidated product revenue gross margins were not significantly impacted by the revenue recognized under the SBB contracts for the three and nine months ended September 30, 2020 and 2019. The Company has substantially completed the first contract and is approximately 65% complete on the second contract with SBB as of September 30, 2020.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment consisted of the following: (In thousands) September 30 December 31 Land $ 75,777 $ 30,409 Land improvements 18,748 19,155 Buildings and improvements 225,406 182,795 Machinery and equipment 1,511,120 1,518,652 Uncompleted construction 64,408 55,592 Gross property, plant and equipment 1,895,459 1,806,603 Less: Accumulated depreciation (1,254,572) (1,244,817) Property, plant and equipment, net $ 640,887 $ 561,786

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	Leases The components of lease expense were as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Finance leases: Amortization expense $ 377 $ 325 $ 1,115 $ 911 Interest on lease liabilities 43 27 139 68 Operating leases 8,558 4,391 21,745 11,518 Variable and short-term lease expense 11,572 6,759 29,169 16,367 Sublease income (51) — (150) — Total lease expense from continuing operations $ 20,499 $ 11,502 $ 52,018 $ 28,864 Supplemental cash flow information related to leases was as follows: Nine Months Ended September 30 (In thousands) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows from operating activities - Operating leases $ 20,512 $ 10,881 Cash flows from financing activities - Finance leases 997 953 ROU assets obtained in exchange for lease obligations: Operating leases (a) $ 62,507 $ 57,607 Finance leases 1,613 1,671 (a) Cash flows for the nine months ended September 30, 2020 include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL. Cash flows for nine months ended September 30, 2019 include ROU assets of approximately $34 million that were recorded upon adoption at January 1, 2019 and approximately $21 million that were recorded upon the acquisition of Clean Earth. See Note 3, Acquisitions and Dispositions, for additional information.. Supplemental balance sheet information related to leases was as follows: (In thousands) September 30 December 31 Operating Leases: Operating lease ROU assets $ 96,800 $ 52,065 Current portion of operating lease liabilities 26,577 $ 12,544 Operating lease liabilities 67,995 36,974 Finance Leases: Property, plant and equipment, net $ 4,179 $ 3,519 Current maturities of long-term debt 1,335 $ 1,237 Long-term debt 2,903 2,218 Supplemental additional information related to leases was as follows: September 30 December 31 Other information: Weighted average remaining lease term - Operating leases (in years) 8.10 11.57 Weighted average remaining lease term - Finance leases (in years) 3.73 4.01 Weighted average discount rate - Operating leases 6.1 % 6.3 % Weighted average discount rate - Finance leases 4.1 % 4.2 % Maturities of lease liabilities were as follows: (In thousand) Operating Finance Year Ending December 31: 2020 (excluding the nine months ended September 30, 2020) $ 8,126 $ 361 2021 27,315 1,330 2022 20,639 1,072 2023 15,818 869 2024 10,655 702 After 2024 41,421 113 Total lease payments 123,974 4,447 Less: Imputed interest (29,402) (209) Total $ 94,572 $ 4,238 The Company's leases, excluding short-term leases, have remaining terms of less than one year to 30 years, some of which include options to extend for up to 10 years, and some of which include options to terminate within one year. As of
Leases	Leases The components of lease expense were as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Finance leases: Amortization expense $ 377 $ 325 $ 1,115 $ 911 Interest on lease liabilities 43 27 139 68 Operating leases 8,558 4,391 21,745 11,518 Variable and short-term lease expense 11,572 6,759 29,169 16,367 Sublease income (51) — (150) — Total lease expense from continuing operations $ 20,499 $ 11,502 $ 52,018 $ 28,864 Supplemental cash flow information related to leases was as follows: Nine Months Ended September 30 (In thousands) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows from operating activities - Operating leases $ 20,512 $ 10,881 Cash flows from financing activities - Finance leases 997 953 ROU assets obtained in exchange for lease obligations: Operating leases (a) $ 62,507 $ 57,607 Finance leases 1,613 1,671 (a) Cash flows for the nine months ended September 30, 2020 include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL. Cash flows for nine months ended September 30, 2019 include ROU assets of approximately $34 million that were recorded upon adoption at January 1, 2019 and approximately $21 million that were recorded upon the acquisition of Clean Earth. See Note 3, Acquisitions and Dispositions, for additional information.. Supplemental balance sheet information related to leases was as follows: (In thousands) September 30 December 31 Operating Leases: Operating lease ROU assets $ 96,800 $ 52,065 Current portion of operating lease liabilities 26,577 $ 12,544 Operating lease liabilities 67,995 36,974 Finance Leases: Property, plant and equipment, net $ 4,179 $ 3,519 Current maturities of long-term debt 1,335 $ 1,237 Long-term debt 2,903 2,218 Supplemental additional information related to leases was as follows: September 30 December 31 Other information: Weighted average remaining lease term - Operating leases (in years) 8.10 11.57 Weighted average remaining lease term - Finance leases (in years) 3.73 4.01 Weighted average discount rate - Operating leases 6.1 % 6.3 % Weighted average discount rate - Finance leases 4.1 % 4.2 % Maturities of lease liabilities were as follows: (In thousand) Operating Finance Year Ending December 31: 2020 (excluding the nine months ended September 30, 2020) $ 8,126 $ 361 2021 27,315 1,330 2022 20,639 1,072 2023 15,818 869 2024 10,655 702 After 2024 41,421 113 Total lease payments 123,974 4,447 Less: Imputed interest (29,402) (209) Total $ 94,572 $ 4,238 The Company's leases, excluding short-term leases, have remaining terms of less than one year to 30 years, some of which include options to extend for up to 10 years, and some of which include options to terminate within one year. As of

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The following table reflects the changes in carrying amounts of goodwill by segment for the nine months ended September 30, 2020: (In thousands) Harsco Environmental Segment Harsco Harsco Rail Consolidated Balance at December 31, 2019 $ 395,113 $ 330,230 $ 13,026 $ 738,369 Changes to goodwill (a) 1,480 144,283 — 145,763 Foreign currency translation (2,221) — — (2,221) Balance at September 30, 2020 $ 394,372 $ 474,513 $ 13,026 $ 881,911 (a) The changes to goodwill primarily relate to the acquisition of ESOL in the Harsco Clean Earth Segment. See Note 3, Acquisitions and Dispositions, and immaterial acquisitions in the Harsco Environmental Segment. The Company tests for goodwill impairment annually, or more frequently if indicators of impairment exist, or if a decision is made to dispose of a business. The Company performs its annual goodwill impairment test as of October 1 and monitors for triggering events on an ongoing basis. The Company determined that, as of September 30, 2020, no interim goodwill impairment testing was necessary. The Company has concluded that no triggering event occurred during the three months ended September 30, 2020. However, a prolonged economic downturn resulting from COVID-19 could impact the Company's future projected cash flows used to estimate fair value, and/or result in a sustained decrease in the Company’s share price, which could indicate an impairment. Intangible assets, net, on the Company's Condensed Consolidated Balance Sheets consist of the following: September 30, 2020 December 31, 2019 (In thousands) Gross Carrying Accumulated Gross Carrying Accumulated Customer related (b) $ 106,247 $ 43,572 $ 143,996 $ 99,327 Permits 308,559 14,992 170,322 4,694 Technology related 37,992 8,187 36,467 5,635 Trade names 31,698 4,133 31,719 2,182 Air rights 26,139 827 26,139 411 Patents 177 126 249 168 Non-compete Agreement 2,500 312 — — Other 3,747 1,228 3,765 1,158 Total $ 517,059 $ 73,377 $ 412,657 $ 113,575 (b) In the quarter ended September 30, 2020 fully amortized intangible assets were removed from the gross carrying and accumulated amortization amounts. Amortization expense for intangible assets was as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Amortization expense for intangible assets $ 8,272 $ 5,668 $ 22,542 $ 9,508 The estimated amortization expense for the next five fiscal years based on current intangible assets is as follows: (In thousands) 2020 2021 2022 2023 2024 Estimated amortization expense (c) $ 31,200 $ 32,300 $ 31,600 $ 31,600 $ 31,100 (c) These estimated amortization expense amounts do not reflect the potential effect of future foreign currency exchange fluctuations.

Debt and Credit Agreements

Debt and Credit Agreements	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt and Credit Agreements	Debt and Credit Agreements In March 2020 the Company raised $280 million pursuant to the New Term Loan as a new tranche under the existing Senior Secured Credit Facilities. The New Term Loan was fully drawn on April 6, 2020 to partially fund the acquisition of ESOL. See Note 3, Acquisition and Dispositions, for additional information related to the ESOL acquisition. Borrowings under the New Term Loan bear interest at a rate per annum ranging from 150 to 225 basis points over adjusted LIBOR (as defined in the Credit Agreement). The New Term Loan will mature on June 28, 2024. The Company capitalized $1.9 million of fees related to the issuance of the New Term Loan. In both March 2020 and June 2020, the Company amended the Senior Secured Credit Facilities to increase the net debt to consolidated adjusted EBITDA ratio covenant. As a result of these amendments, the net debt to consolidated adjusted EBITDA ratio covenant has been increased to 5.75 through March 2021 and then decreasing quarterly until reaching 4.75 in December 2021. There is no change to the previously agreed interest rates as long as the Company's total leverage ratio does not equal or exceed 4.50, at which time it would increase by 25 basis points. During the nine months ended September 30, 2020, the Company recognized $1.9 million of fees and expenses related to the amended Senior Secured Credit Facilities in the caption Unused debt commitment and amendment fees on the Condensed Consolidated Statements of Operations.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Three Months Ended September 30 Defined Benefit Pension Plans Net Periodic Pension Cost (Benefit) U.S. Plans International Plans (In thousands) 2020 2019 2020 2019 Service costs $ — $ 10 $ 448 $ 344 Interest costs 1,845 2,637 4,474 5,168 Expected return on plan assets (2,842) (2,602) (10,405) (8,671) Recognized prior service costs — — 113 61 Recognized loss 1,225 1,395 3,737 3,326 Settlement/curtailment losses — — — — Defined benefit pension plans net periodic pension cost (benefit) $ 228 $ 1,440 $ (1,633) $ 228 Nine Months Ended September 30 Defined Benefit Pension Plans Net Periodic Pension Cost (Benefit) U.S. Plans International Plans (In thousands) 2020 2019 2020 2019 Service costs $ — $ 30 $ 1,303 $ 1,057 Interest costs 5,535 7,939 13,104 16,380 Expected return on plan assets (8,526) (7,788) (30,428) (27,507) Recognized prior service costs — — 326 192 Recognized loss 3,875 4,205 10,924 10,556 Settlement/curtailment losses — 129 — — Defined benefit pension plans net periodic pension cost (benefit) $ 884 $ 4,515 $ (4,771) $ 678 Three Months Ended Nine Months Ended Company Contributions September 30 September 30 (In thousands) 2020 2019 2020 2019 Defined benefit pension plans (U.S.) $ 453 $ 2,806 $ 2,940 $ 6,296 Defined benefit pension plans (International) 2,682 4,121 14,235 16,522 Multiemployer pension plans 390 527 1,178 1,531 Defined contribution pension plans 2,870 2,358 7,936 8,717

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax benefit related to continuing operations for the three and nine months ended September 30, 2020 was $1.7 million and $4.6 million, respectively. Income tax expense related to continuing operations for the three and nine months ended September 30, 2019 was $12.6 million and $17.8 million, respectively. Income tax benefit for the three and nine months ended September 30, 2020 compared with income tax expense for the same periods in 2019 is the result of lower pretax income, primarily resulting from decreased operating income due to impacts of COVID-19 and incremental acquisition and integration costs in connection with the Company's acquisitions of approximately $8.1 million and $23.9 million for the three and nine months ended September 30, 2020, respectively, as well as a $2.8 million favorable income tax adjustment in connection with an increase in estimated usage of assumed net operating losses related to the Clean Earth acquisition and a $2.8 million valuation allowance adjustment against a deferred tax asset due to a lower projected income in a certain jurisdiction in 2019 not recurring in 2020.An income tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon examination, based on technical merits, including resolutions of any related appeals or litigation processes. The reserve for uncertain tax positions at September 30, 2020 was $4.0 million, including interest and penalties.  Within the next twelve months, it is reasonably possible that $0.3 million unrecognized income tax benefits will be recognized upon settlement of tax examinations and the expiration of various statutes of limitations.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Environmental The Company is involved in a number of environmental remediation investigations and cleanups and, along with other companies, has been identified as a “potentially responsible party” for certain byproduct disposal sites. While each of these matters is subject to various uncertainties, it is probable that the Company will agree to make payments toward funding certain of these activities, and it is possible that some of these matters will be decided unfavorably to the Company. The Company has evaluated its potential liability and its financial exposure is dependent upon such factors as the continuing evolution of environmental laws and regulatory requirements, the availability and application of technology, the allocation of cost among potentially responsible parties, the years of remedial activity required and the remediation methods selected. The Company evaluates its liability for future environmental remediation costs on a quarterly basis. Although actual costs to be incurred at identified sites in future periods may vary from the estimates (given inherent uncertainties in evaluating environmental exposures), the Company does not expect that any costs that are reasonably possible to be incurred by the Company in connection with environmental matters in excess of the amounts accrued would have a material adverse effect on the Company's financial condition, results of operations or cash flows. The following table summarizes information related to the location and undiscounted amount of the Company's environmental liabilities: (In thousands) September 30 December 31 Current portion of environmental liabilities (a) $ 6,031 $ 3,431 Long-term environmental liabilities 29,747 5,600 Total environmental liabilities $ 35,778 $ 9,031 (a) The current portion of environmental liabilities is included in the caption Other current liabilities on the Company's Condensed Consolidated Balance Sheets. Environmental liabilities relate primarily to the ESOL business which was acquired on April 6, 2020. As part of the ESOL acquisition, the Company assumed control of certain closed sites that were being monitored as part of ongoing environmental remediation plans. See Note 3, Acquisitions and Dispositions, for additional details. On June 25 and 26, 2018, the DTSC conducted a compliance enforcement inspection of ESOL’s facility in Rancho Cordova, California, which was then owned by Stericycle, Inc. On February 14, 2020, the DTSC filed an action in the Superior Court for the State of California, Sacramento Division, alleging violations of California’s Hazardous Waste Control Law and the facility’s hazardous waste permit arising from the inspection. On August 27, 2020 the DTSC issued a Notice of Denial of Hazardous Waste Facility Permit Application. On September 25, 2020, the Company filed an administrative appeal. The DTSC investigation was ongoing well before the Company's acquisition of the ESOL business, and the Company was aware of the investigation and many of the issues raised in the investigation at the time of the purchase. Accordingly, the Company is indemnified for certain fines and other costs and expenses associated with this matter by Stericycle, Inc. As a result, the administrative appeal will be led by Stericycle, Inc. The Company has not accrued any amounts in respect of these alleged violations and cannot estimate the reasonably possible loss or the range of reasonably possible losses that it may incur. As previously disclosed, the Company has had ongoing meetings with the SCE over processing salt cakes, a processing byproduct, stored at the Al Hafeerah site. The Company’s Bahrain operations that produced the salt cakes has ceased operations and are owned under a strategic venture for which its strategic venture partner owns a 35% minority interest. An Environmental Impact Assessment and Technical Feasibility Study for facilities to process the salt cakes was approved by the SCE during the first quarter of 2018. The Company currently expects those facilities to commence operations during the fourth quarter of 2020. The Company has previously established a reserve of $7.0 million, which represents the Company's best estimate of the ultimate costs to be incurred to resolve this matter. The Company continues to evaluate this reserve and any future change in estimated costs could be material to the Company’s results of operations in any one period. On July 27, 2018 Brazil’s Federal and Rio de Janeiro State Public Prosecution Offices (MPF and MPE) filed a Civil Public Action against one of the Company's customers (CSN), the Company’s Brazilian subsidiary, the Municipality of Volta Redonda, Brazil, and the Instituto Estadual do Ambiente (local environmental protection agency) seeking the implementation of various measures to limit and reduce the accumulation of customer-owned slag at the site in Brazil. On August 6, 2018 the 3rd Federal Court in Volta Redonda granted the MPF and MPE an injunction against the same parties requiring, among other things, CSN and the Company’s Brazilian subsidiary to limit the volume of slag sent to the site. Because the customer owns the site and the slag located on the site, the Company believes that complying with this injunction is the steel producer’s responsibility. On March 18, 2019 the Court issued an order fining the Company 5,000 Brazilian reais per day (or approximately $900 per day) and CSN 20,000 Brazilian reais per day (or approximately $4,000 per day) until the requirements of the injunction are met. On November 1, 2019 the Court issued an additional order increasing the fines assessed to the Company to 25,000 Brazilian reais per day (or approximately $4,000 per day) and raising the fines assessed to CSN to 100,000 Brazilian reais per day (or approximately $18,000 per day). The Court also assessed an additional fine of 10,000,000 Brazilian reais (or approximately $1,800,000) against CSN and the Company jointly. The Company is appealing the fines and the underlying injunction. Both the Company and CSN continue to have discussions with the governmental authorities on the injunction and the possible resolution of the underlying case. The Company does not believe that a loss relating to this matter is probable or estimable at this point. On October 19, 2018 local environmental authorities issued an enforcement action against the Company concerning the Company’s operations at a customer site in Ijmuiden, Netherlands. The enforcement action alleges violations of the Company’s environmental permit at the site, which restricts the release of any visible dust emissions. The enforcement action ordered the Company to cease all violations of the permit by October 31, 2018. The authorities have issued three additional enforcement actions since that time and have asserted fines of approximately $0.7 million which the Company has recorded, with the possibility of additional fines for any future violations. The Company is vigorously contesting the enforcement action and fines and is also working with its customer to ensure the control of emissions. The Company has contractual indemnity rights from its customer, should it be required to pay the assessed fines. On June 13, 2019 the PA DEP indicated to the Company and a landowner who received processed slag from the Company that it plans to require action to bring the landowner’s site into compliance and to assess a civil penalty against the Company and the landowner. The Company is working with the landowner and PA DEP to determine the most effective way to address PA DEP’s concerns about the site and has established a $0.4 million reserve, which represents the Company’s best estimate of the costs to bring the landowner's site into compliance. On March 24, 2017 the Allegheny County Health Department issued a notice of violation against the Company concerning the Company’s operations at a customer site in Natrona, Pennsylvania. On January 21, 2020 the Company paid $0.1 million to settle the civil penalties accrued up to that date. On May 4, 2020, the Company paid a $5 thousand penalty and on August 21, 2020, the Company paid a $6 thousand penalty, both for alleged additional events. The Company also received an additional assessment of $8 thousand on October 23, 2020. It is possible the Company could incur additional penalties for future violations. Pursuant to the settlement agreement, the Company and its customer have also agreed to construct and bring certain slag processing operations into a building. On October 29, 2020, one of the residents of Natrona filed a punitive class action lawsuit against the Company in the Court of Common Pleas of Allegheny County, Pennsylvania, seeking unspecified damages and injunctive relief due to alleged dust emissions at the site, which the Company believes is without merit. DEA Investigation Prior to the Company’s acquisition of ESOL, Stericycle, Inc, notified the Company that the DEA had served an administrative subpoena on Stericycle, Inc. and executed a search warrant at a facility in Rancho Cordova, California and an administrative inspection warrant at a facility in Indianapolis, Indiana. The Company has determined that the DEA and the DTSC have launched investigations involving, at least in part, the ESOL business of collecting, transporting, and destroying controlled substances from retail customers that transferred from Stericycle, Inc. to the Company. In connection with these investigations, the DEA also executed a search warrant on an ESOL facility in Austin Texas on July 2, 2020. The Company is cooperating with these inquiries, which relate primarily to the period before the Company owned the ESOL business. Since the acquisition of the ESOL business, the Company has performed a vigorous review of ESOL’s compliance program related to controlled substances and has made material changes to the manner in which controlled substances are transported from retail customers to DEA-registered facilities for destruction. The Company has not accrued any amounts in respect of these investigations and cannot estimate the reasonably possible loss or the range of reasonably possible losses that it may incur, if any. Investigations of this type are, by their nature, uncertain and unpredictable. While it is the Company’s position that it has recourse for some or all liabilities, if any, that arise from these matters under the ESOL purchase agreement and representations and warranties insurance policies purchased by the Company, there can be no assurances that the Company’s position will ultimately prevail. Brazilian Tax Disputes The Company is involved in a number of tax disputes with federal, state and municipal tax authorities in Brazil. These disputes are at various stages of the legal process, including the administrative review phase and the collection action phase, and include assessments of fixed amounts of principal and penalties, plus interest charges that increase at statutorily determined amounts per month and are assessed on the aggregate amount of the principal and penalties. In addition, the losing party, at the collection action or court of appeals phase, could be subject to a charge to cover statutorily mandated legal fees, which are generally calculated as a percentage of the total assessed amounts due, inclusive of penalty and interest. Many of the claims relate to ICMS, services and social security tax disputes. The largest proportion of the assessed amounts relate to ICMS claims filed by the SPRA, encompassing the period from January 2002 to May 2005. In October 2009 the Company received notification of the SPRA’s final administrative decision regarding the levying of ICMS in the State of São Paulo in relation to services provided to a customer in the State between January 2004 and May 2005. As of September 30, 2020 the principal amount of the tax assessment from the SPRA with regard to this case is approximately $1.1 million, with penalty, interest and fees assessed to date increasing such amount by an additional $15.0 million. On June 4, 2018 the Appellate Court of the State of Sao Paulo ruled in favor of the SPRA but ruled that the assessed penalty should be reduced to approximately $1.1 million. After calculating the interest accrued on the penalty, the Company estimates that this ruling reduces the current overall potential liability for this case to approximately $6.4 million. All such amounts include the effect of foreign currency translation. The Company has appealed the ruling in favor of the SPRA to the Superior Court of Justice. Due to multiple court precedents in the Company’s favor, as well as the Company’s ability to appeal, the Company does not believe a loss is probable. Another ICMS tax case involving the SPRA refers to the tax period from January 2002 to December 2003. In December 2018 the administrative tribunal hearing the case upheld the Company's liability. The Company has appealed to the judicial phase. The aggregate amount assessed by the tax authorities in August 2005 was $4.5 million (the amounts with regard to this claim are valued as of the date of the assessment since it has not yet reached the collection phase), composed of a principal amount of $1.1 million, with penalty and interest assessed through that date increasing such amount by an additional $3.4 million. On December 6, 2018 the administrative tribunal reduced the applicable penalties to $0.8 million. After calculating the interest accrued on the current penalty, the Company estimates that the current overall liability for this case to be approximately $9.0 million. All such amounts include the effect of foreign currency translation. Due to multiple court precedents in the Company's favor the Company does not believe a loss is probable. The Company continues to believe that sufficient coverage for these claims exists as a result of the indemnification obligations of the Company's customer and such customer’s pledge of assets in connection with the October 2009 notice, as required by Brazilian law. The Company intends to continue its practice of vigorously defending itself against these tax claims under various alternatives, including judicial appeal. The Company will continue to evaluate its potential liability with regard to these claims on a quarterly basis; however, it is not possible to predict the ultimate outcome of these tax-related disputes in Brazil. No loss provision has been recorded in the Company's condensed consolidated financial statements for the disputes described above because the loss contingency is not deemed probable, and the Company does not expect that any costs that are reasonably possible to be incurred by the Company in connection with Brazilian tax disputes would have a material adverse effect on the Company's financial condition, results of operations or cash flows. Brazilian Labor Disputes The Company is subject to ongoing collective bargaining and individual labor claims in Brazil through the Harsco Environmental Segment which allege, among other things, the Company's failure to pay required amounts for overtime and vacation at certain sites. The Company is vigorously defending itself against these claims; however, litigation is inherently unpredictable, particularly in foreign jurisdictions. While the Company does not currently expect that the ultimate resolution of these claims will have a material adverse effect on the Company’s financial condition, results of operations or cash flows, it is not possible to predict the ultimate outcome of these labor-related disputes. As of September 30, 2020 and December 31, 2019 the Company has established reserves of $4.3 million and $6.5 million, respectively, on the Company's Condensed Consolidated Balance Sheets for amounts considered to be probable and estimable. Customer Disputes The Company may, in the normal course of business, become involved in commercial disputes with subcontractors or customers. Although results of operations and cash flows for a given period could be adversely affected by a negative outcome in these or other lawsuits, claims or proceedings, management believes that the ultimate outcome of any ongoing matters will not have a material adverse effect on the Company's financial condition, results of operations or cash flows. Other The Company is named as one of many defendants (approximately 90 or more in most cases) in legal actions in the U.S. alleging personal injury from exposure to airborne asbestos over the past several decades. In their suits, the plaintiffs have named as defendants, among others, many manufacturers, distributors and installers of numerous types of equipment or products that allegedly contained asbestos. The Company believes that the claims against it are without merit. The Company has never been a producer, manufacturer or processor of asbestos fibers. Any asbestos-containing part of a Company product used in the past was purchased from a supplier and the asbestos encapsulated in other materials such that airborne exposure, if it occurred, was not harmful and is not associated with the types of injuries alleged in the pending actions. At September 30, 2020 there were approximately 17,160 pending asbestos personal injury actions filed against the Company. Of those actions, approximately 16,596 were filed in the New York Supreme Court (New York County), approximately 119 were filed in other New York State Supreme Court Counties and approximately 445 were filed in courts located in other states. The complaints in most of those actions generally follow a form that contains a standard damages demand of $20 million or $25 million, regardless of the individual plaintiff’s alleged medical condition, and without identifying any specific Company product. At September 30, 2020 approximately 16,550 of the actions filed in New York Supreme Court (New York County) were on the Deferred/Inactive Docket created by the court in December 2002 for all pending and future asbestos actions filed by persons who cannot demonstrate that they have a malignant condition or discernible physical impairment. The remaining approximately 46 cases in New York County are pending on the Active or In Extremis Docket created for plaintiffs who can demonstrate a malignant condition or physical impairment. The Company has liability insurance coverage under various primary and excess policies that the Company believes will be available, if necessary, to substantially cover any liability that might ultimately be incurred in the asbestos actions referred to above. The costs and expenses of the asbestos actions are being paid by the Company's insurers. In view of the persistence of asbestos litigation in the U.S., the Company expects to continue to receive additional claims in the future. The Company intends to continue its practice of vigorously defending these claims and cases. At September 30, 2020 the Company has obtained dismissal in approximately 28,300 cases by stipulation or summary judgment prior to trial. It is not possible to predict the ultimate outcome of asbestos-related actions in the U.S. due to the unpredictable nature of this litigation, and no loss provision has been recorded in the Company's condensed consolidated financial statements because a loss contingency is not deemed probable or estimable. Despite this uncertainty, and although results of operations and cash flows for a given period could be adversely affected by asbestos-related actions, the Company does not expect that any costs that are reasonably possible to be incurred by the Company in connection with asbestos litigation would have a material adverse effect on the Company's financial condition, results of operations or cash flows. The Company is subject to various other claims and legal proceedings covering a wide range of matters that arose in the ordinary course of business. In the opinion of management, all such matters are adequately covered by insurance or by established reserves, and, if not so covered, are without merit or are of such kind, or involve such amounts, as would not have a material adverse effect on the financial position, results of operations or cash flows of the Company. Insurance liabilities are recorded when it is probable that a liability has been incurred for a particular event and the amount of loss associated with the event can be reasonably estimated. Insurance reserves have been estimated based primarily upon actuarial calculations and reflect the undiscounted estimated liabilities for ultimate losses, including claims incurred but not reported. Inherent in these estimates are assumptions that are based on the Company's history of claims and losses, a detailed analysis of existing claims with respect to potential value, and current legal and legislative trends. If actual claims differ from those projected by management, changes (either increases or decreases) to insurance reserves may be required and would be recorded through income in the period the change was determined. When a recognized liability is covered by third-party insurance, the Company records an insurance claim receivable to reflect the covered liability. Insurance claim receivables are included in Other receivables on the Company's Condensed Consolidated Balance Sheets. See Note 1, Summary of Significant Accounting Policies, to the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 for additional information on Accrued insurance and loss reserves.

Reconciliation of Basic and Dil

Reconciliation of Basic and Diluted Shares	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Shares	Reconciliation of Basic and Diluted Shares Three Months Ended Nine Months Ended September 30 September 30 (In thousands, except per share amounts) 2020 2019 2020 2019 Income (loss) from continuing operations attributable to Harsco Corporation common stockholders $ (7,843) $ 17,831 $ (27,375) $ 25,453 Weighted-average shares outstanding: Weighted-average shares outstanding - basic 79,000 79,666 78,916 79,966 Dilutive effect of stock-based compensation — 1,444 — 1,783 Weighted-average shares outstanding - diluted 79,000 81,110 78,916 81,749 Earnings (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders: Basic $ (0.10) $ 0.22 $ (0.35) $ 0.32 Diluted $ (0.10) $ 0.22 $ (0.35) $ 0.31 The following average outstanding stock-based compensation units were not included in the computation of diluted earnings per share because the effect was antidilutive: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Restricted stock units 691 — 723 — Stock appreciation rights 2,383 599 2,499 460 Performance share units 857 265 894 166

Derivative Instruments, Hedging

Derivative Instruments, Hedging Activities and Fair Value	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments, Hedging Activities and Fair Value	Derivative Instruments, Hedging Activities and Fair Value Derivative Instruments and Hedging Activities The Company uses derivative instruments, including foreign currency exchange forward contracts, interest rate swaps and CCIRs, to manage certain foreign currency and interest rate exposures. Derivative instruments are viewed as risk management tools by the Company and are not used for trading or speculative purposes. All derivative instruments are recorded on the Company's Condensed Consolidated Balance Sheets at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risks, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. The Company primarily applies the market approach for recurring fair value measurements and endeavors to utilize the best available information. Accordingly, the Company utilizes valuation techniques that maximize the use of observable inputs, such as forward rates, interest rates, the Company’s credit risk and counterparties’ credit risks, and which minimize the use of unobservable inputs. The Company is able to classify fair value balances based on the ability to observe those inputs. Foreign currency exchange forward contracts, interest rate swaps and CCIRs are based upon pricing models using market-based inputs (Level 2). Model inputs can be verified and valuation techniques do not involve significant management judgment. The fair value of outstanding derivative contracts recorded as assets and liabilities on the Company's Condensed Consolidated Balance Sheets was as follows: (In thousands) Balance Sheet Location Fair Value of Derivatives Designated as Hedging Instruments Fair Value of Derivatives Not Designated as Hedging Instruments Total Fair Value September 30, 2020 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 2,178 $ 509 $ 2,687 Total $ 2,178 $ 509 $ 2,687 (In thousands) Balance Sheet Location Fair Value of Derivatives Designated as Hedging Instruments Fair Value of Derivatives Not Designated as Hedging Instruments Total Fair Value Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 287 $ 8,833 $ 9,120 Interest rate swaps Other current liabilities 3,822 — 3,822 Interest rate swaps Other liabilities 4,542 — 4,542 Total $ 8,651 $ 8,833 $ 17,484 December 31, 2019 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 2,039 $ 946 $ 2,985 Total $ 2,039 $ 946 $ 2,985 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 140 $ 3,733 $ 3,873 Interest rate swaps Other current liabilities 2,098 — 2,098 Interest rate swaps Other liabilities 4,281 — 4,281 Total $ 6,519 $ 3,733 $ 10,252 All of the Company's derivatives are recorded on the Company's Condensed Consolidated Balance Sheets at gross amounts and not offset. All of the Company's interest rate swaps, CCIRs and certain foreign currency exchange forward contracts are transacted under ISDA documentation. Each ISDA master agreement permits the net settlement of amounts owed in the event of default. The Company's derivative assets and liabilities subject to enforceable master netting arrangements, if offset, would not have resulted in a net asset or liability at September 30, 2020 or December 31, 2019. The effect of derivative instruments on the Company's Condensed Consolidated Statements of Operations and Condensed Consolidated Statements of Comprehensive Income (Loss) was as follows: Derivatives Designated as Hedging Instruments Amount Recognized in Location of Amount Reclassified from Amount Reclassified from Three Months Ended Three Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts $ (1,244) $ 808 Product revenues $ 174 $ (512) Interest rate swaps (95) (930) Interest expense 739 (76) CCIRs (a) (24) 51 Interest expense 312 291 $ (1,363) $ (71) $ 1,225 $ (297) Amount Recognized in Location of Amount Reclassified from AOCI into Income Amount Reclassified from Nine Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts $ 834 $ 765 Product revenues/Cost of services sold $ (1,562) $ (933) Interest rate swaps — — Income from discontinued businesses — 2,741 Interest rate swaps (3,835) (8,566) Interest expense 1,849 (648) CCIRs (a) 39 53 Interest expense 912 908 $ (2,962) $ (7,748) $ 1,199 $ 2,068 (a) Amounts represent changes in foreign currency translation related to balances in AOCI. The location and amount of gain (loss) recognized on the Company's Condensed Consolidated Statements of Operations was as follows: Three Months Ended September 30 2020 2019 (in thousands) Product Revenues Interest Expense Product Revenues Cost of Services Sold Interest Expense Total amounts of line items presented in the Condensed Consolidated Statement of Operations in which the effects of cash flow hedges are recorded $ 125,119 $ (15,794) $ 106,488 $ 239,519 $ (12,819) Interest rate swaps: Gain or (loss) reclassified from AOCI into income — (739) — — 76 Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income (174) — 512 — — Amount excluded from effectiveness testing recognized in earnings based on changes in fair value 12 — 86 — — Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach 3 — — — — CCIRs: Loss reclassified from AOCI into income — (312) — — (291) Nine Months Ended September 30 2020 2019 (in thousands) Product Revenues Interest Expense Product Revenues Cost of Services Sold Interest Expense Income From Discontinued Operations Total amounts of line items presented in the Condensed Consolidated Statement of Operations in which the effects of cash flow hedges are recorded $ 334,324 $ (43,396) $ 319,765 $ 608,230 $ (24,429) $ 23,958 Interest rate swaps: Gain or (loss) reclassified from AOCI into income — (1,849) — — 648 — Loss reclassified from AOCI into income as a result that a forecasted transaction is no longer probable of occurring — — — — — (2,741) Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income 1,562 — 977 (44) — — Amount excluded from effectiveness testing recognized in earnings based on changes in fair value 208 — 403 — — — Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach 24 — — — — — CCIRs: Loss reclassified from AOCI into income — (912) — — (908) — Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives (b) Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts Cost of services and products sold $ (12,279) $ 10,642 $ (5,001) $ 15,735 (b) These gains (losses) offset amounts recognized in cost of services and products sold principally as a result of intercompany or third party foreign currency exposures. Foreign Currency Exchange Forward Contracts The Company conducts business in multiple currencies and, accordingly, is subject to the inherent risks associated with foreign exchange rate movements. Foreign currency-denominated assets and liabilities are translated into U.S. dollars at the exchange rates existing at the respective consolidated balance sheet dates, and income and expense items are translated at the average exchange rates during the respective periods. The Company uses derivative instruments to hedge cash flows related to foreign currency fluctuations. Foreign currency exchange forward contracts outstanding are part of a worldwide program to minimize foreign currency exchange operating income and balance sheet exposure by offsetting foreign currency exposures of certain future payments between the Company and various subsidiaries, suppliers or customers. The unsecured contracts are with major financial institutions. The Company may be exposed to credit loss in the event of non-performance by the contract counterparties. The Company evaluates the creditworthiness of the counterparties and does not expect default by them. Foreign currency exchange forward contracts are used to hedge commitments, such as foreign currency debt, firm purchase commitments and foreign currency cash flows for certain export sales transactions. Changes in the fair value of derivatives used to hedge foreign currency denominated balance sheet items are reported directly in earnings, along with offsetting transaction gains and losses on the items being hedged. Derivatives used to hedge forecasted cash flows associated with foreign currency commitments may be accounted for as cash flow hedges, as deemed appropriate, if the criteria for hedge accounting are met. Gains and losses on derivatives designated as cash flow hedges are deferred in AOCI, a separate component of equity, and reclassified to earnings in a manner that matches the timing of the earnings impact of the hedged transactions. The ineffective portion of all hedges, if any, is recognized currently in earnings. At September 30, 2020 and December 31, 2019 the notional amounts of foreign currency exchange forward contracts were $431.6 million and $496.3 million, respectively. These contracts are primarily denominated in British Pound Sterling and Euros and mature through October 2021. In addition to foreign currency exchange forward contracts, the Company designates certain loans as hedges of net investments in international subsidiaries. The Company recorded pre-tax net gains of $4.6 million for the three months ended September 30, 2020 and pre-tax net losses of $7.4 million for the nine months ended September 30, 2020 and pre-tax net losses of $3.0 million and $3.7 million for the three and nine months ended September 30, 2019, respectively, in AOCI. Interest Rate Swaps The Company uses interest rate swaps in conjunction with certain variable rate debt issuances in order to secure a fixed interest rate. Changes in the fair value attributed to the effect of the swaps’ interest spread and changes in the credit worthiness of the counter-parties are recorded in AOCI. In January 2017 and February 2018 the Company entered into a series of interest rate swaps that cover the period from 2018 through 2022 and had the effect of converting $300.0 million of the Original Term Loan from floating-rate to fixed-rate. The fixed rates provided by the swaps replace the adjusted LIBOR rate in the interest calculation, ranging from 2.45% for 2020 to 3.12% for 2022. During June 2019 the Company effected the early termination of interest rate swaps that covered the period from 2019 through 2022 and had the effect of converting $100.0 million of the Original Term Loan from floating-rate to fixed-rate. This termination was conducted as a result of the Company's new Notes offering and required repayment of a portion of the Original Term Loan with proceeds from the AXC disposal. The total notional amount of the Company's interest rate swaps is $200.0 million as of September 30, 2020. Cross-Currency Interest Rate Swaps The Company may use CCIRs in conjunction with certain debt issuances in order to secure a fixed local currency interest rate. Under these CCIRs, the Company receives interest based on a fixed or floating U.S. dollar rate and pays interest on a fixed local currency rate based on the contractual amounts in dollars and the local currency, respectively. At maturity, there is also the payment of principal amounts between currencies. Changes in the fair value attributed to the effect of the swaps' interest spread and changes in the credit worthiness of the counter-parties are recorded in AOCI. Changes in value attributed to the effect of foreign currency fluctuations are recorded on the Company's Condensed Consolidated Statements of Operations and offset currency fluctuation effects on the debt principal. The Company had no outstanding CCIRs at September 30, 2020. Fair Value of Other Financial Instruments The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, accrued liabilities and short-term borrowings approximate fair value due to the short-term maturities of these assets and liabilities. At September 30, 2020 and

Review of Operations by Segment

Review of Operations by Segment	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Review of Operations by Segment	Review of Operations by Segment Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Revenues From Continuing Operations (a) Harsco Environmental $ 222,507 $ 260,883 $ 668,057 $ 791,533 Harsco Clean Earth 194,098 87,639 434,489 87,639 Harsco Rail 92,793 74,633 252,974 224,783 Total Revenues From Continuing Operations $ 509,398 $ 423,155 $ 1,355,520 $ 1,103,955 Operating Income (Loss) From Continuing Operations (a) Harsco Environmental $ 12,317 $ 32,794 $ 36,400 $ 84,868 Harsco Clean Earth 8,902 11,308 12,945 11,308 Harsco Rail 4,059 12,115 19,162 26,947 Corporate (20,214) (9,472) (58,694) (38,755) Total Operating Income From Continuing Operations $ 5,064 $ 46,745 $ 9,813 $ 84,368 Depreciation (a) Harsco Environmental $ 25,588 $ 25,557 $ 75,626 $ 79,074 Harsco Clean Earth 5,010 2,359 12,769 2,359 Harsco Rail 1,258 1,192 3,730 3,414 Corporate 497 716 1,531 2,094 Total Depreciation $ 32,353 $ 29,824 $ 93,656 $ 86,941 Amortization (a) Harsco Environmental $ 1,970 $ 1,751 $ 5,827 $ 5,436 Harsco Clean Earth 6,218 3,834 16,463 3,834 Harsco Rail 85 84 252 238 Corporate (b) 776 481 2,179 1,872 Total Amortization $ 9,049 $ 6,150 $ 24,721 $ 11,380 Capital Expenditures (a) Harsco Environmental $ 21,700 $ 48,348 $ 65,102 $ 122,606 Harsco Clean Earth 2,647 3,204 7,134 3,204 Harsco Rail 3,474 3,280 6,310 13,561 Corporate 62 109 444 1,549 Total Capital Expenditures $ 27,883 $ 54,941 $ 78,990 $ 140,920 (a) The Company's acquisition of ESOL closed on April 6, 2020 and the Company's acquisition of Clean Earth closed on June 28, 2019. The operating results of the former Harsco Industrial Segment have been reflected as discontinued operations in the Company's Condensed Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (b) Amortization expense on Corporate relates to the amortization of deferred financing costs. Reconciliation of Segment Operating Income to Income (Loss) From Continuing Operations Before Income Taxes and Equity Income Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Segment operating income $ 25,278 $ 56,217 $ 68,507 $ 123,123 General Corporate expense (20,214) (9,472) (58,694) (38,755) Operating income from continuing operations 5,064 46,745 9,813 84,368 Interest income 604 445 1,613 1,569 Interest expense (15,794) (12,819) (43,396) (24,429) Unused debt commitment and amendment fees — (158) (1,920) (7,593) Defined benefit pension income (expense) 1,859 (1,356) 5,171 (4,166) Income (loss) from continuing operations before income taxes and equity income $ (8,267) $ 32,857 $ (28,719) $ 49,749

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition The Company recognizes revenues to depict the transfer of promised services and products to customers in an amount that reflects the consideration the Company expects to receive in exchange for those services or products. Service revenues include the Harsco Clean Earth Segment and the service components of the Harsco Environmental and Harsco Rail Segments. Product revenues include portions of the Harsco Environmental and Harsco Rail Segments. A summary of the Company's revenues by primary geographical markets as well as by key product and service groups is as follows: Three Months Ended September 30, 2020 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 58,973 $ 194,098 $ 62,805 $ 315,876 Western Europe 92,506 — 21,416 113,922 Latin America (c) 29,085 — 412 29,497 Asia-Pacific 22,079 — 8,160 30,239 Middle East and Africa 15,558 — — 15,558 Eastern Europe 4,306 — — 4,306 Total Revenues $ 222,507 $ 194,098 $ 92,793 $ 509,398 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 181,640 $ — $ — $ 181,640 Applied products 38,166 — — 38,166 Environmental systems for aluminum dross and scrap processing 2,701 — — 2,701 Railway track maintenance equipment — — 55,493 55,493 After market parts and services; safety and diagnostic technology — — 29,100 29,100 Railway contracting services — — 8,200 8,200 Waste processing, recycling, reuse and transportation solutions — 194,098 — 194,098 Total Revenues $ 222,507 $ 194,098 $ 92,793 $ 509,398 Three Months Ended September 30, 2019 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 78,076 $ 87,639 $ 56,923 $ 222,638 Western Europe 93,426 — 10,409 103,835 Latin America (c) 35,127 — 551 35,678 Asia-Pacific 34,529 — 6,750 41,279 Middle East and Africa 15,302 — — 15,302 Eastern Europe 4,423 — — 4,423 Total Revenues $ 260,883 $ 87,639 $ 74,633 $ 423,155 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 218,788 $ — $ — $ 218,788 Applied products 34,890 — — 34,890 Environmental systems for aluminum dross and scrap processing 7,205 — — 7,205 Railway track maintenance equipment — — 30,233 30,233 After market parts and services; safety and diagnostic technology — — 37,100 37,100 Railway contracting services — — 7,300 7,300 Waste processing, recycling, reuse and transportation solutions — 87,639 — 87,639 Total Revenues $ 260,883 $ 87,639 $ 74,633 $ 423,155 Nine Months Ended September 30, 2020 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 186,210 $ 434,489 $ 173,039 $ 793,738 Western Europe 271,795 — 56,435 328,230 Latin America (c) 87,453 — 1,592 89,045 Asia-Pacific 63,969 — 21,908 85,877 Middle East and Africa 46,240 — — 46,240 Eastern Europe 12,390 — — 12,390 Total Revenues $ 668,057 $ 434,489 $ 252,974 $ 1,355,520 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 563,159 $ — $ — $ 563,159 Applied products 95,019 — — 95,019 Environmental systems for aluminum dross and scrap processing 9,879 — — 9,879 Railway track maintenance equipment — — 138,519 138,519 After market parts and services; safety and diagnostic technology — — 92,800 92,800 Railway contracting services — — 21,655 21,655 Waste processing, recycling, reuse and transportation solutions — 434,489 — 434,489 Total Revenues $ 668,057 $ 434,489 $ 252,974 $ 1,355,520 Nine Months Ended September 30, 2019 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 229,537 $ 87,639 $ 172,566 $ 489,742 Western Europe 290,125 — 30,960 321,085 Latin America (c) 108,390 — 1,915 110,305 Asia-Pacific 104,446 — 19,342 123,788 Middle East and Africa 44,959 — — 44,959 Eastern Europe 14,076 — — 14,076 Total Revenues $ 791,533 $ 87,639 $ 224,783 $ 1,103,955 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 673,244 $ — $ — $ 673,244 Applied products 98,966 — — 98,966 Environmental systems for aluminum dross and scrap processing 19,323 — — 19,323 Railway track maintenance equipment — — 102,801 102,801 After market parts and services; safety and diagnostic technology — — 105,101 105,101 Railway contracting services — — 16,881 16,881 Waste processing, recycling, reuse and transportation solutions — 87,639 — 87,639 Total Revenues $ 791,533 $ 87,639 $ 224,783 $ 1,103,955 (a) The Company's acquisition of ESOL closed on April 6, 2020 and the Company's acquisition of Clean Earth closed on June 28, 2019. The results of both are included in the Harsco Clean Earth Segment. The operating results of the former Harsco Industrial Segment have been reflected as discontinued operations in the Company's Condensed Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (b) Revenues are attributed to individual countries based on the location of the facility generating the revenue. (c) Includes Mexico. The Company may receive payments in advance of earning revenue, which are treated as Advances on contracts on the Company's Condensed Consolidated Balance Sheets. The Company may recognize revenue in advance of being able to contractually invoice the customer, which is treated as Contract assets on the Company's Condensed Consolidated Balance Sheets. Non-current contract assets are included in Other assets on the Company's Condensed Consolidated Balance Sheets. Contract assets are transferred to Trade accounts receivable, net, when the right to payment becomes unconditional. Contract assets and Contract liabilities are reported as a net position, on a contract-by-contract basis, at the end of each reporting period. These instances are primarily related to the Harsco Rail Segment. The Company had Contract assets totaling $57.6 million and $31.2 million at September 30, 2020 and December 31, 2019, respectively. The increase is due principally to recognition of additional contract assets in excess of contract assets transferred to accounts receivable during the nine months ended September 30, 2020, primarily in the Harsco Rail Segment. The Company had Advances on contracts totaling $86.0 million and $60.3 million at September 30, 2020 and December 31, 2019, respectively. The increase is due principally to the receipt of new advances on contracts in excess of recognition of revenue partially offset by revenue recognized related to advances in the Harsco Rail Segment. During the three and nine months ended September 30, 2020 the Company recognized approximately $20 million and $55 million, respectively, of revenue related to amounts previously included in Advances on contracts. During the three and nine months ended September 30, 2019 the Company recognized approximately $17 million and $53 million, respectively, of revenue related to amounts previously included in Advances on contracts. Additionally, during the three months ended September 30, 2019, the Company recognized revenue of $0.8 million, in the Harsco Rail Segment, related to performance obligations partially satisfied in prior periods. At September 30, 2020 the Harsco Environmental Segment had remaining, fixed, unsatisfied performance obligations where the expected contract duration exceeds one year totaling $102.5 million. Of this amount, $30.1 million is expected to be fulfilled by September 30, 2021, $20.1 million by September 30, 2022, $15.8 million by September 30, 2023, $13.2 million by September 30, 2024 and the remainder thereafter. These amounts exclude any variable fees, fixed fees subject to indexation and any performance obligations expected to be satisfied within one year. The decrease from December 31, 2019 is primarily due to the renegotiation of a contract with a customer in the U.K. who had entered into administration.

Other (Income) Expenses, Net

Other (Income) Expenses, Net	9 Months Ended
	Sep. 30, 2020
Other Income and Expenses [Abstract]
Other (Income) Expenses	Other Expenses, Net The major components of this Condensed Consolidated Statements of Operations caption were as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Employee termination benefit costs $ 798 $ 1,591 $ 6,694 $ 5,107 Other costs to exit activities 13 918 478 3,265 Impaired asset write-downs 2 129 75 343 Contingent consideration adjustments 2,437 (906) 2,437 (4,417) Net gains (7) (1,353) (255) (3,624) Other 390 4 (355) (265) Other expenses, net $ 3,633 $ 383 $ 9,074 $ 409

Components of Accumulated Other

Components of Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss	Components of Accumulated Other Comprehensive Loss The components of AOCI, net of the effect of income taxes, and activity for the nine months ended September 30, 2019 and 2020 was as follows: Components of AOCI, Net of Tax (In thousands) Cumulative Foreign Exchange Translation Adjustments Effective Portion of Derivatives Designated as Hedging Instruments Cumulative Unrecognized Actuarial Losses on Pension Obligations Unrealized Gain (Loss) on Marketable Securities Total Balance at December 31, 2018 $ (159,810) $ 1,389 $ (408,655) $ (31) $ (567,107) Adoption of new accounting standard — — (21,429) (a) — (21,429) OCI before reclassifications (20,513) (b) (5,889) (c) 11,630 (b) 19 (14,753) Amounts reclassified from AOCI, net of tax (1,763) 1,404 14,021 — 13,662 Total OCI (22,276) (4,485) 25,651 19 (1,091) OCI attributable to noncontrolling interests 1,868 — — — 1,868 OCI attributable to Harsco Corporation (20,408) (4,485) 25,651 19 777 Balance at September 30, 2019 $ (180,218) $ (3,096) $ (404,433) $ (12) $ (587,759) Components of AOCI, Net of Tax (In thousands) Cumulative Foreign Exchange Translation Adjustments Effective Portion of Derivatives Designated as Hedging Instruments Cumulative Unrecognized Actuarial Losses on Pension Obligations Unrealized Gain (Loss) on Marketable Securities Total Balance at December 31, 2019 $ (143,340) $ (3,717) $ (440,562) $ (3) $ (587,622) OCI before reclassifications (48,150) (b) (2,226) (c) 9,905 (b) (22) (40,493) Amounts reclassified from AOCI, net of tax 12,906 604 18,132 — 31,642 Total OCI (35,244) (1,622) 28,037 (22) (8,851) OCI attributable to noncontrolling interests (579) — — — (579) OCI attributable to Harsco Corporation (35,823) (1,622) 28,037 (22) (9,430) Balance at September 30, 2020 $ (179,163) $ (5,339) $ (412,525) $ (25) $ (597,052) (a) Represents the adoption of the new accounting standard on January 1, 2019 related to stranded tax effects from the Tax Cuts and Jobs Act. (b) Principally foreign currency fluctuation. (c) Net change from periodic revaluations. Amounts reclassified from AOCI were as follows: (In thousands) Three Months Ended Nine Months Ended Location on the Condensed Consolidated Statements of Operations September 30 September 30 2020 2019 2020 2019 Recognition of cumulative foreign currency translation adjustments: Gain on substantial liquidation of subsidiaries (d) $ — $ (154) $ 12,906 $ (2,425) Other expenses, net Loss on substantial liquidation of subsidiaries (d) — 662 — 662 Gain on sale of discontinued businesses Amortization of cash flow hedging instruments: Foreign currency exchange forward contracts $ 174 $ (512) $ (1,562) $ (977) Product revenues Foreign currency exchange forward contracts — — — 44 Cost of services sold CCIRs 312 291 912 908 Interest expense Interest rate swaps 739 (76) 1,849 (648) Interest expense Interest rate swaps — — — 2,741 Income from discontinued businesses Total before taxes 1,225 (297) 1,199 2,068 Income taxes (408) (21) (595) (664) Total reclassification of cash flow hedging instruments, net of tax $ 817 $ (318) $ 604 $ 1,404 Amortization of defined benefit pension items (e) : Recognized losses $ 4,962 $ 4,721 $ 14,799 $ 14,761 Defined benefit pension income (expense) Recognized prior service costs 113 61 326 192 Defined benefit pension income (expense) Settlement/curtailment losses — — — 129 Defined benefit pension income (expense) Pension liability transfer - discontinued business — — 5,363 — Gain on sale of discontinued businesses Total before taxes 5,075 4,782 20,488 15,082 Income taxes (323) (340) (2,356) (1,061) Total reclassification of defined benefit pension items, net of tax $ 4,752 $ 4,442 $ 18,132 $ 14,021 (d) No tax impact. (e) These AOCI components are included in the computation of net periodic pension costs. See Note 10, Employee Benefit Plans, for additional details.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared these unaudited condensed consolidated financial statements in accordance with U.S. GAAP for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X of the SEC. Accordingly, the unaudited condensed consolidated financial statements do not include all information and disclosure required by U.S. GAAP for annual financial statements. The December 31, 2019 Condensed Consolidated Balance Sheet information contained in this Quarterly Report on Form 10-Q was derived from the 2019 audited consolidated financial statements. The unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements, including the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. In the opinion of management, all adjustments (all of which are of a normal recurring nature) that are necessary for a fair statement are reflected in the unaudited condensed consolidated financial statements. Restricted Cash The Company had restricted cash of $2.3 million and $2.5 million at September 30, 2020 and December 31, 2019, respectively, and the restrictions are primarily related to collateral provided for certain guarantees of the Company's performance. Acquisition of ESOL On April 6, 2020 the Company completed the previously announced acquisition of ESOL, an established waste transportation, processing and services provider with a comprehensive portfolio of disposal solutions for customers primarily across the industrial, retail and healthcare markets, from Stericycle, Inc. for $429.0 million in cash, inclusive of post-closing adjustments. See Note 3, Acquisitions and Dispositions, for additional information. Segment Reporting The Company reports information about operating segments using the "management approach," which is based on the way management organizes and reports the segments within the enterprise for making operating decisions and assessing performance. The Company's reportable segments are identified based upon differences in products, service and markets served. The operations of ESOL are combined and included as part of the Harsco Clean Earth Segment. Impact of COVID-19 Beginning in early 2020, overall global economic conditions were significantly impacted by COVID-19. The continuing impact of COVID-19 on the Company varies by end market as well as local conditions (including applicable government mandates) and is continually evolving. The ultimate duration and impact of COVID-19 on the Company and its customers' operations is presently unclear, though the Company continues to operate as a provider of certain essential services in the U.S. and other countries. The Company continues to take significant and proactive actions to protect all stakeholders and to minimize the operational and financial impacts of COVID-19 where possible. The Company did not record any long-lived asset impairments, indefinite-lived asset impairments, goodwill impairments, significant inventory write-downs or incremental accounts receivable reserves for current expected credit losses during the three months or nine months ended September 30, 2020, however such charges are possible in future periods, which could have an adverse effect on the Company's future results of operations, cash flows, or financial condition. Discontinued Operations In January 2020 the Company sold IKG and, together with the 2019 sales of AXC and PK, this completed the divestiture of the former Harsco Industrial Segment originally announced in May 2019. These disposals represent a strategic shift and accelerated the transformation of the Company's portfolio of businesses into a leading provider of environmental solutions and services. As a result of these disposals (i) the carrying value of the remaining assets and liabilities of the Harsco Industrial Segment were classified as Assets held-for-sale and Liabilities of assets held-for-sale on the Company's December 31, 2019 Condensed Consolidated Balance Sheet; (ii) the operating results of the Harsco Industrial Segment, costs directly related to the disposals, an allocation of interest expense associated with mandatory debt repayments required as a result of the disposals and the write-off of deferred financing costs resulting from the mandatory repayment have been reflected in the Company's Condensed Consolidated Statements of Operations as discontinued operations for all periods presented; and (iii) all disclosures have been updated to reflect these changes. See Note 3, Acquisitions and Dispositions, for additional information.
Recently Adopted and Recently Issued Accounting Standards	Recently Adopted and Recently Issued Accounting Standards The following accounting standards have been adopted in 2020: On January 1, 2020 the Company adopted changes issued by the FASB which updated the impairment model for credit losses by requiring entities to use a forward-looking approach based on expected losses rather than incurred losses to estimate credit losses on certain types of financial instruments, including trade receivables. Provisions for receivables will be recorded as Allowance for expected credit losses, replacing the previously utilized Allowance for doubtful accounts. In addition, these changes required certain expanded disclosures. Other than changes in disclosure, these changes did not have a material impact on the Company's condensed consolidated financial statements as the calculation of expected credit losses did not yield results that were materially different from the methodology previously utilized by the Company. See Note 4, Accounts Receivable and Note Receivable for additional information. On January 1, 2020 the Company adopted changes issued by the FASB that removed the second step of the annual goodwill impairment test, which required a hypothetical purchase price allocation. The changes provide that the amount of goodwill impairment will be equal to the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. All other goodwill impairment guidance remains largely unchanged. The same one-step impairment test will be applied to goodwill at all reporting units, even those with zero or negative carrying amounts. Entities will be required to disclose the amount of goodwill at reporting units with zero or negative carrying amounts. These changes did not have a material impact on the Company's condensed consolidated financial statements. On January 1, 2020 the Company adopted changes issued by the FASB which modified the disclosure requirements for fair value measurements. The amendments in this update remove the requirement to disclose the amount of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy; and the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. The changes require disclosure of changes in unrealized gains and losses for the period included in OCI for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Other than required expanded disclosures, the adoption of these changes did not have a material impact on the Company's condensed consolidated financial statements. The following accounting standards have been issued and become effective for the Company at a future date: In December 2019 the FASB issued changes which are intended to reduce complexity and simplify the accounting for income taxes in accordance with U.S. GAAP by removing certain exceptions related to investments, intraperiod allocations and interim calculations and clarifying existing guidance to improve consistent application. The changes become effective for the Company on January 1, 2021. Management does not believe these changes will have a material impact on its condensed consolidated financial statements. In March 2020 the FASB issued changes that provide companies with optional guidance to ease the potential accounting burden associated with transitioning from reference rates that are expected to be discontinued. In response to the concerns about risks of IBORs and, particularly, the risk of cessation of LIBOR, regulators in several jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction-based and less susceptible to manipulation. The changes provide optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The changes can be adopted no later than December 31, 2022 with early adoption permitted. Management does not believe these changes will have a material impact on its condensed consolidated financial statements. In August 2020, the FASB issued changes which simplified the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. Management concluded that this standard will not have an impact on its condensed consolidated financial statements.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Summary of assets acquired and liabilities assumed	The preliminary fair value recorded for the assets acquired and liabilities assumed for ESOL is as follows: Preliminary Valuation (In millions) April 6 Measurement Period Adjustments September 30 Cash and cash equivalents $ 0.4 $ — $ 0.4 Trade accounts receivable 124.1 (0.9) 123.2 Inventory 5.0 — 5.0 Other current assets 0.7 (0.4) 0.3 Property, plant and equipment 105.3 — 105.3 Right-of-use assets 56.0 — 56.0 Goodwill 152.0 (8.1) 143.9 Intangible assets 161.0 — 161.0 Other assets 0.2 — 0.2 Accounts payable (48.6) (0.4) (49.0) Accrued expenses (17.5) — (17.5) Current portion of operating lease liabilities (16.6) — (16.6) Other current liabilities (6.4) — (6.4) Environmental liabilities (24.4) — (24.4) Deferred income taxes (15.5) — (15.5) Operating lease liabilities (39.4) — (39.4) Total identifiable net assets of ESOL 436.3 (9.8) 426.5 Non-compete agreement 2.5 — 2.5 Total identifiable net assets of ESOL, including non-compete agreement $ 438.8 $ (9.8) $ 429.0 The fair value recorded for the assets acquired and liabilities assumed for Clean Earth is as follows: Final (In millions) Measurement Period Adjustments (a) September 30 Cash and cash equivalents (b) $ 42.8 $ (39.2) $ 3.6 Trade accounts receivable, net 63.7 (1.2) 62.5 Other receivables 0.8 1.3 2.1 Other current assets 8.7 (1.4) 7.3 Property, plant and equipment 75.6 1.4 77.0 Right-of-use assets 14.4 11.4 25.8 Goodwill 313.8 16.8 330.6 Intangible assets 261.1 (18.9) 242.2 Other assets 4.0 (2.8) 1.2 Accounts payable (23.0) (0.1) (23.1) Acquisition consideration payable (b) (39.2) 39.2 — Other current liabilities (18.0) (1.7) (19.7) Net deferred taxes liabilities (51.2) 5.5 (45.7) Operating lease liabilities (11.1) (8.4) (19.5) Other liabilities (6.5) (2.1) (8.6) Total identifiable net assets of Clean Earth $ 635.9 $ (0.2) $ 635.7 (a) The measurement period adjustments did not have a material impact on the Company's previously reported operating results. (b) Acquisition consideration payable represents a portion of the cash consideration not paid out until July 2019.
Preliminary valuation of identifiable intangible assets and amortization periods	The following table details the preliminary valuation of identifiable intangible assets and amortization periods for ESOL and the non-compete agreement entered into by the Company upon acquisition of ESOL: Preliminary Valuation (Dollars in millions) Weighted-Average Amortization Period April 6 Measurement Period Adjustments September 30 Permits and rights 22 years $ 138.0 $ — $ 138.0 Customer relationships 10 years 23.0 — 23.0 Total identifiable intangible assets of ESOL 161.0 — 161.0 Non-compete agreement 4 years 2.5 — 2.5 Total identifiable intangible assets acquired $ 163.5 $ — $ 163.5 The following table details the valuation of identifiable intangible assets and amortization periods for Clean Earth: Final (In millions) Weighted-Average Amortization Period Preliminary Measurement Period Adjustments (c) September 30 Permits 18 years $ 176.1 $ (6.0) $ 170.1 Customer relationships 8 years 33.4 (12.9) 20.5 Air rights Usage based (d) 25.6 — 25.6 Trade names 12 years 26.0 — 26.0 Total identifiable intangible assets of Clean Earth $ 261.1 $ (18.9) $ 242.2 (c) The measurement period adjustments did not have a material impact on the Company's previously reported operating results. (d) The Company estimates that based on current usage that the expected useful life would be 27 years.
Pro forma information	Three Months Ended Nine Months Ended September 30 September 30 (In millions) 2020 2019 2020 2019 Pro forma revenues $ 509.4 $ 572.7 $ 1,486.2 $ 1,650.3 Pro forma net income attributed to Harsco Corporation (including discontinued operations) (e) (1.8) 434.9 1.0 440.9 (e) Pro forma net income for the three and nine months ended September 30, 2019 includes a $417.5 million after-tax gain on the sale of AXC.
Balance sheet positions and financial information included in net income from discontinued operations and statements of cash flows	Certain key selected financial information included in net income (loss) from discontinued operations for the former Harsco Industrial Segment is as follows: Three Months Ended Nine Months Ended September 30 September 30 (In millions) 2020 2019 2020 2019 Amounts for the former Harsco Industrial Segment: Total revenues $ — $ 39,855 $ 10,203 $ 274,037 Cost of products sold — 28,174 8,082 201,188 Gain on sale from discontinued business — 527,980 18,371 527,980 Income (loss) from discontinued business (716) 803 (593) 24,877 Additional amounts allocated to the former Harsco Industrial Segment: Selling, general and administrative expenses (f) $ 521 $ 1,994 $ 1,710 $ 5,521 Interest expense (g) — — — 11,237 Loss on early extinguishment of debt (h) — 5,314 — 5,314 (f) The Company has allocated directly attributable transaction costs to discontinued operations. In addition, this caption includes costs directly attributable to retained contingent liabilities of the Harsco Industrial Segment. (g) The Company has allocated interest expense, including a portion of the amount reclassified into income for the Company's interest rate swaps and amortization of deferred financing costs resulting from the AXC disposal, as part of discontinued operations. (h) The Company has allocated the $5.3 million write-off of deferred financing costs to discontinued operations as it is directly attributable to the mandatory repayment of the Original Term Loan that resulted from the AXC disposal. The following is selected financial information included on the Company's Condensed Consolidated Statements of Cash Flows attributable to the former Harsco Industrial Segment: Nine Months Ended September 30 (In millions) 2020 2019 Non-cash operating items Depreciation and amortization $ — $ 3,301 Cash flows from investing activities Purchases of property, plant and equipment 106 6,151

Accounts Receivable (Tables)

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Schedule of accounts receivable	Accounts receivable consist of the following: (In thousands) September 30 December 31 Trade accounts receivable $ 409,928 $ 323,502 Less: Allowance for expected credit losses and doubtful accounts (a) (b) (8,934) (13,512) Trade accounts receivable, net $ 400,994 $ 309,990 Other receivables (c) $ 38,325 $ 21,265 (a) The decrease in the allowance for expected credit losses and doubtful accounts is the final write-off of previously fully-reserved balances in the Harsco Environmental Segment. (b) Upon the acquisition of ESOL, trade accounts receivable totaling $136.2 million were recorded at a fair value of $123.2 million as of the acquisition date, due primarily to expected credit losses as of the acquisition date of $13.0 million which were netted against the gross receivable balance as of the acquisition date. (c) Other receivables include employee receivables, insurance receivable, tax claims and refunds and other miscellaneous items not included in Trade accounts receivable, net. (In thousands) September 30 December 31 Note receivable $ 35,389 $ —
Schedule of provision for doubtful accounts related to trade accounts receivable	The change in the provision for expected credit losses and doubtful accounts related to trade accounts receivable was as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Provision for expected credit losses and doubtful accounts related to trade accounts receivable $ 861 $ 1,116 $ 1,098 $ 6,539

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Schedule of inventories	Inventories consist of the following: (In thousands) September 30 December 31 Finished goods $ 14,736 $ 14,550 Work-in-process 13,489 13,088 Raw materials and purchased parts 111,754 104,488 Stores and supplies 30,058 24,865 Total inventories $ 170,037 $ 156,991

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	Property, plant and equipment consisted of the following: (In thousands) September 30 December 31 Land $ 75,777 $ 30,409 Land improvements 18,748 19,155 Buildings and improvements 225,406 182,795 Machinery and equipment 1,511,120 1,518,652 Uncompleted construction 64,408 55,592 Gross property, plant and equipment 1,895,459 1,806,603 Less: Accumulated depreciation (1,254,572) (1,244,817) Property, plant and equipment, net $ 640,887 $ 561,786

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Components of Lease Expense and Supplemental Cash Flow and Additional Information	he components of lease expense were as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Finance leases: Amortization expense $ 377 $ 325 $ 1,115 $ 911 Interest on lease liabilities 43 27 139 68 Operating leases 8,558 4,391 21,745 11,518 Variable and short-term lease expense 11,572 6,759 29,169 16,367 Sublease income (51) — (150) — Total lease expense from continuing operations $ 20,499 $ 11,502 $ 52,018 $ 28,864 Supplemental cash flow information related to leases was as follows: Nine Months Ended September 30 (In thousands) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows from operating activities - Operating leases $ 20,512 $ 10,881 Cash flows from financing activities - Finance leases 997 953 ROU assets obtained in exchange for lease obligations: Operating leases (a) $ 62,507 $ 57,607 Finance leases 1,613 1,671 (a) Cash flows for the nine months ended September 30, 2020 include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL. Cash flows for nine months ended September 30, 2019 include ROU assets of approximately $34 million that were recorded upon adoption at January 1, 2019 and approximately $21 million that were recorded upon the acquisition of Clean Earth. See Note 3, Acquisitions and Dispositions, for additional information.. Supplemental additional information related to leases was as follows: September 30 December 31 Other information: Weighted average remaining lease term - Operating leases (in years) 8.10 11.57 Weighted average remaining lease term - Finance leases (in years) 3.73 4.01 Weighted average discount rate - Operating leases 6.1 % 6.3 % Weighted average discount rate - Finance leases 4.1 % 4.2 %
Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases was as follows: (In thousands) September 30 December 31 Operating Leases: Operating lease ROU assets $ 96,800 $ 52,065 Current portion of operating lease liabilities 26,577 $ 12,544 Operating lease liabilities 67,995 36,974 Finance Leases: Property, plant and equipment, net $ 4,179 $ 3,519 Current maturities of long-term debt 1,335 $ 1,237 Long-term debt 2,903 2,218
Maturities of Operating Lease Liabilities	Maturities of lease liabilities were as follows: (In thousand) Operating Finance Year Ending December 31: 2020 (excluding the nine months ended September 30, 2020) $ 8,126 $ 361 2021 27,315 1,330 2022 20,639 1,072 2023 15,818 869 2024 10,655 702 After 2024 41,421 113 Total lease payments 123,974 4,447 Less: Imputed interest (29,402) (209) Total $ 94,572 $ 4,238
Maturities of Finance Lease Liabilities	Maturities of lease liabilities were as follows: (In thousand) Operating Finance Year Ending December 31: 2020 (excluding the nine months ended September 30, 2020) $ 8,126 $ 361 2021 27,315 1,330 2022 20,639 1,072 2023 15,818 869 2024 10,655 702 After 2024 41,421 113 Total lease payments 123,974 4,447 Less: Imputed interest (29,402) (209) Total $ 94,572 $ 4,238
Future Minimum Payments Under Operating Leases with Noncancelable Terms	(In thousand) Operating Finance Year Ending December 31: 2020 (excluding the nine months ended September 30, 2020) $ 8,126 $ 361 2021 27,315 1,330 2022 20,639 1,072 2023 15,818 869 2024 10,655 702 After 2024 41,421 113 Total lease payments 123,974 4,447 Less: Imputed interest (29,402) (209) Total $ 94,572 $ 4,238

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in carrying amounts of goodwill by segment	The following table reflects the changes in carrying amounts of goodwill by segment for the nine months ended September 30, 2020: (In thousands) Harsco Environmental Segment Harsco Harsco Rail Consolidated Balance at December 31, 2019 $ 395,113 $ 330,230 $ 13,026 $ 738,369 Changes to goodwill (a) 1,480 144,283 — 145,763 Foreign currency translation (2,221) — — (2,221) Balance at September 30, 2020 $ 394,372 $ 474,513 $ 13,026 $ 881,911 (a) The changes to goodwill primarily relate to the acquisition of ESOL in the Harsco Clean Earth Segment. See Note 3, Acquisitions and Dispositions, and immaterial acquisitions in the Harsco Environmental Segment.
Schedule of intangible assets by class	Intangible assets, net, on the Company's Condensed Consolidated Balance Sheets consist of the following: September 30, 2020 December 31, 2019 (In thousands) Gross Carrying Accumulated Gross Carrying Accumulated Customer related (b) $ 106,247 $ 43,572 $ 143,996 $ 99,327 Permits 308,559 14,992 170,322 4,694 Technology related 37,992 8,187 36,467 5,635 Trade names 31,698 4,133 31,719 2,182 Air rights 26,139 827 26,139 411 Patents 177 126 249 168 Non-compete Agreement 2,500 312 — — Other 3,747 1,228 3,765 1,158 Total $ 517,059 $ 73,377 $ 412,657 $ 113,575 (b) In the quarter ended September 30, 2020 fully amortized intangible assets were removed from the gross carrying and accumulated amortization amounts.
Schedule of amortization expense	Amortization expense for intangible assets was as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Amortization expense for intangible assets $ 8,272 $ 5,668 $ 22,542 $ 9,508
Schedule of estimated amortization expense	The estimated amortization expense for the next five fiscal years based on current intangible assets is as follows: (In thousands) 2020 2021 2022 2023 2024 Estimated amortization expense (c) $ 31,200 $ 32,300 $ 31,600 $ 31,600 $ 31,100

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Schedule of net benefit costs	Three Months Ended September 30 Defined Benefit Pension Plans Net Periodic Pension Cost (Benefit) U.S. Plans International Plans (In thousands) 2020 2019 2020 2019 Service costs $ — $ 10 $ 448 $ 344 Interest costs 1,845 2,637 4,474 5,168 Expected return on plan assets (2,842) (2,602) (10,405) (8,671) Recognized prior service costs — — 113 61 Recognized loss 1,225 1,395 3,737 3,326 Settlement/curtailment losses — — — — Defined benefit pension plans net periodic pension cost (benefit) $ 228 $ 1,440 $ (1,633) $ 228 Nine Months Ended September 30 Defined Benefit Pension Plans Net Periodic Pension Cost (Benefit) U.S. Plans International Plans (In thousands) 2020 2019 2020 2019 Service costs $ — $ 30 $ 1,303 $ 1,057 Interest costs 5,535 7,939 13,104 16,380 Expected return on plan assets (8,526) (7,788) (30,428) (27,507) Recognized prior service costs — — 326 192 Recognized loss 3,875 4,205 10,924 10,556 Settlement/curtailment losses — 129 — — Defined benefit pension plans net periodic pension cost (benefit) $ 884 $ 4,515 $ (4,771) $ 678
Schedule of contributions to pension plans	Three Months Ended Nine Months Ended Company Contributions September 30 September 30 (In thousands) 2020 2019 2020 2019 Defined benefit pension plans (U.S.) $ 453 $ 2,806 $ 2,940 $ 6,296 Defined benefit pension plans (International) 2,682 4,121 14,235 16,522 Multiemployer pension plans 390 527 1,178 1,531 Defined contribution pension plans 2,870 2,358 7,936 8,717

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of Loss Contingencies by Contingency	The following table summarizes information related to the location and undiscounted amount of the Company's environmental liabilities: (In thousands) September 30 December 31 Current portion of environmental liabilities (a) $ 6,031 $ 3,431 Long-term environmental liabilities 29,747 5,600 Total environmental liabilities $ 35,778 $ 9,031 (a) The current portion of environmental liabilities is included in the caption Other current liabilities on the Company's Condensed Consolidated Balance Sheets.

Reconciliation of Basic and D_2

Reconciliation of Basic and Diluted Shares (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Reconciliation of basic and diluted shares	Three Months Ended Nine Months Ended September 30 September 30 (In thousands, except per share amounts) 2020 2019 2020 2019 Income (loss) from continuing operations attributable to Harsco Corporation common stockholders $ (7,843) $ 17,831 $ (27,375) $ 25,453 Weighted-average shares outstanding: Weighted-average shares outstanding - basic 79,000 79,666 78,916 79,966 Dilutive effect of stock-based compensation — 1,444 — 1,783 Weighted-average shares outstanding - diluted 79,000 81,110 78,916 81,749 Earnings (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders: Basic $ (0.10) $ 0.22 $ (0.35) $ 0.32 Diluted $ (0.10) $ 0.22 $ (0.35) $ 0.31
Schedule of antidilutive securities excluded from computation of earnings per share	The following average outstanding stock-based compensation units were not included in the computation of diluted earnings per share because the effect was antidilutive: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Restricted stock units 691 — 723 — Stock appreciation rights 2,383 599 2,499 460 Performance share units 857 265 894 166

Derivative Instruments, Hedgi_2

Derivative Instruments, Hedging Activities and Fair Value (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of fair value of outstanding derivative contracts	The fair value of outstanding derivative contracts recorded as assets and liabilities on the Company's Condensed Consolidated Balance Sheets was as follows: (In thousands) Balance Sheet Location Fair Value of Derivatives Designated as Hedging Instruments Fair Value of Derivatives Not Designated as Hedging Instruments Total Fair Value September 30, 2020 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 2,178 $ 509 $ 2,687 Total $ 2,178 $ 509 $ 2,687 (In thousands) Balance Sheet Location Fair Value of Derivatives Designated as Hedging Instruments Fair Value of Derivatives Not Designated as Hedging Instruments Total Fair Value Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 287 $ 8,833 $ 9,120 Interest rate swaps Other current liabilities 3,822 — 3,822 Interest rate swaps Other liabilities 4,542 — 4,542 Total $ 8,651 $ 8,833 $ 17,484 December 31, 2019 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 2,039 $ 946 $ 2,985 Total $ 2,039 $ 946 $ 2,985 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 140 $ 3,733 $ 3,873 Interest rate swaps Other current liabilities 2,098 — 2,098 Interest rate swaps Other liabilities 4,281 — 4,281 Total $ 6,519 $ 3,733 $ 10,252
Schedule of effect of derivative instruments	Derivatives Designated as Hedging Instruments Amount Recognized in Location of Amount Reclassified from Amount Reclassified from Three Months Ended Three Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts $ (1,244) $ 808 Product revenues $ 174 $ (512) Interest rate swaps (95) (930) Interest expense 739 (76) CCIRs (a) (24) 51 Interest expense 312 291 $ (1,363) $ (71) $ 1,225 $ (297) Amount Recognized in Location of Amount Reclassified from AOCI into Income Amount Reclassified from Nine Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts $ 834 $ 765 Product revenues/Cost of services sold $ (1,562) $ (933) Interest rate swaps — — Income from discontinued businesses — 2,741 Interest rate swaps (3,835) (8,566) Interest expense 1,849 (648) CCIRs (a) 39 53 Interest expense 912 908 $ (2,962) $ (7,748) $ 1,199 $ 2,068 (a) Amounts represent changes in foreign currency translation related to balances in AOCI. The location and amount of gain (loss) recognized on the Company's Condensed Consolidated Statements of Operations was as follows: Three Months Ended September 30 2020 2019 (in thousands) Product Revenues Interest Expense Product Revenues Cost of Services Sold Interest Expense Total amounts of line items presented in the Condensed Consolidated Statement of Operations in which the effects of cash flow hedges are recorded $ 125,119 $ (15,794) $ 106,488 $ 239,519 $ (12,819) Interest rate swaps: Gain or (loss) reclassified from AOCI into income — (739) — — 76 Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income (174) — 512 — — Amount excluded from effectiveness testing recognized in earnings based on changes in fair value 12 — 86 — — Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach 3 — — — — CCIRs: Loss reclassified from AOCI into income — (312) — — (291) Nine Months Ended September 30 2020 2019 (in thousands) Product Revenues Interest Expense Product Revenues Cost of Services Sold Interest Expense Income From Discontinued Operations Total amounts of line items presented in the Condensed Consolidated Statement of Operations in which the effects of cash flow hedges are recorded $ 334,324 $ (43,396) $ 319,765 $ 608,230 $ (24,429) $ 23,958 Interest rate swaps: Gain or (loss) reclassified from AOCI into income — (1,849) — — 648 — Loss reclassified from AOCI into income as a result that a forecasted transaction is no longer probable of occurring — — — — — (2,741) Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income 1,562 — 977 (44) — — Amount excluded from effectiveness testing recognized in earnings based on changes in fair value 208 — 403 — — — Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach 24 — — — — — CCIRs: Loss reclassified from AOCI into income — (912) — — (908) — Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives (b) Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Foreign currency exchange forward contracts Cost of services and products sold $ (12,279) $ 10,642 $ (5,001) $ 15,735 (b) These gains (losses) offset amounts recognized in cost of services and products sold principally as a result of intercompany or third party foreign currency exposures.

Review of Operations by Segme_2

Review of Operations by Segment (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of operations by segment	Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Revenues From Continuing Operations (a) Harsco Environmental $ 222,507 $ 260,883 $ 668,057 $ 791,533 Harsco Clean Earth 194,098 87,639 434,489 87,639 Harsco Rail 92,793 74,633 252,974 224,783 Total Revenues From Continuing Operations $ 509,398 $ 423,155 $ 1,355,520 $ 1,103,955 Operating Income (Loss) From Continuing Operations (a) Harsco Environmental $ 12,317 $ 32,794 $ 36,400 $ 84,868 Harsco Clean Earth 8,902 11,308 12,945 11,308 Harsco Rail 4,059 12,115 19,162 26,947 Corporate (20,214) (9,472) (58,694) (38,755) Total Operating Income From Continuing Operations $ 5,064 $ 46,745 $ 9,813 $ 84,368 Depreciation (a) Harsco Environmental $ 25,588 $ 25,557 $ 75,626 $ 79,074 Harsco Clean Earth 5,010 2,359 12,769 2,359 Harsco Rail 1,258 1,192 3,730 3,414 Corporate 497 716 1,531 2,094 Total Depreciation $ 32,353 $ 29,824 $ 93,656 $ 86,941 Amortization (a) Harsco Environmental $ 1,970 $ 1,751 $ 5,827 $ 5,436 Harsco Clean Earth 6,218 3,834 16,463 3,834 Harsco Rail 85 84 252 238 Corporate (b) 776 481 2,179 1,872 Total Amortization $ 9,049 $ 6,150 $ 24,721 $ 11,380 Capital Expenditures (a) Harsco Environmental $ 21,700 $ 48,348 $ 65,102 $ 122,606 Harsco Clean Earth 2,647 3,204 7,134 3,204 Harsco Rail 3,474 3,280 6,310 13,561 Corporate 62 109 444 1,549 Total Capital Expenditures $ 27,883 $ 54,941 $ 78,990 $ 140,920 (a) The Company's acquisition of ESOL closed on April 6, 2020 and the Company's acquisition of Clean Earth closed on June 28, 2019. The operating results of the former Harsco Industrial Segment have been reflected as discontinued operations in the Company's Condensed Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (b) Amortization expense on Corporate relates to the amortization of deferred financing costs.
Reconciliation of segment operating income to income from continuing operations before income taxes and equity income	Reconciliation of Segment Operating Income to Income (Loss) From Continuing Operations Before Income Taxes and Equity Income Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Segment operating income $ 25,278 $ 56,217 $ 68,507 $ 123,123 General Corporate expense (20,214) (9,472) (58,694) (38,755) Operating income from continuing operations 5,064 46,745 9,813 84,368 Interest income 604 445 1,613 1,569 Interest expense (15,794) (12,819) (43,396) (24,429) Unused debt commitment and amendment fees — (158) (1,920) (7,593) Defined benefit pension income (expense) 1,859 (1,356) 5,171 (4,166) Income (loss) from continuing operations before income taxes and equity income $ (8,267) $ 32,857 $ (28,719) $ 49,749

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Summary of revenues by primary geographical markets	A summary of the Company's revenues by primary geographical markets as well as by key product and service groups is as follows: Three Months Ended September 30, 2020 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 58,973 $ 194,098 $ 62,805 $ 315,876 Western Europe 92,506 — 21,416 113,922 Latin America (c) 29,085 — 412 29,497 Asia-Pacific 22,079 — 8,160 30,239 Middle East and Africa 15,558 — — 15,558 Eastern Europe 4,306 — — 4,306 Total Revenues $ 222,507 $ 194,098 $ 92,793 $ 509,398 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 181,640 $ — $ — $ 181,640 Applied products 38,166 — — 38,166 Environmental systems for aluminum dross and scrap processing 2,701 — — 2,701 Railway track maintenance equipment — — 55,493 55,493 After market parts and services; safety and diagnostic technology — — 29,100 29,100 Railway contracting services — — 8,200 8,200 Waste processing, recycling, reuse and transportation solutions — 194,098 — 194,098 Total Revenues $ 222,507 $ 194,098 $ 92,793 $ 509,398 Three Months Ended September 30, 2019 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 78,076 $ 87,639 $ 56,923 $ 222,638 Western Europe 93,426 — 10,409 103,835 Latin America (c) 35,127 — 551 35,678 Asia-Pacific 34,529 — 6,750 41,279 Middle East and Africa 15,302 — — 15,302 Eastern Europe 4,423 — — 4,423 Total Revenues $ 260,883 $ 87,639 $ 74,633 $ 423,155 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 218,788 $ — $ — $ 218,788 Applied products 34,890 — — 34,890 Environmental systems for aluminum dross and scrap processing 7,205 — — 7,205 Railway track maintenance equipment — — 30,233 30,233 After market parts and services; safety and diagnostic technology — — 37,100 37,100 Railway contracting services — — 7,300 7,300 Waste processing, recycling, reuse and transportation solutions — 87,639 — 87,639 Total Revenues $ 260,883 $ 87,639 $ 74,633 $ 423,155 Nine Months Ended September 30, 2020 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 186,210 $ 434,489 $ 173,039 $ 793,738 Western Europe 271,795 — 56,435 328,230 Latin America (c) 87,453 — 1,592 89,045 Asia-Pacific 63,969 — 21,908 85,877 Middle East and Africa 46,240 — — 46,240 Eastern Europe 12,390 — — 12,390 Total Revenues $ 668,057 $ 434,489 $ 252,974 $ 1,355,520 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 563,159 $ — $ — $ 563,159 Applied products 95,019 — — 95,019 Environmental systems for aluminum dross and scrap processing 9,879 — — 9,879 Railway track maintenance equipment — — 138,519 138,519 After market parts and services; safety and diagnostic technology — — 92,800 92,800 Railway contracting services — — 21,655 21,655 Waste processing, recycling, reuse and transportation solutions — 434,489 — 434,489 Total Revenues $ 668,057 $ 434,489 $ 252,974 $ 1,355,520 Nine Months Ended September 30, 2019 (In thousands) Harsco Environmental Segment Harsco Harsco Consolidated Totals Primary Geographical Markets (a) (b) : North America $ 229,537 $ 87,639 $ 172,566 $ 489,742 Western Europe 290,125 — 30,960 321,085 Latin America (c) 108,390 — 1,915 110,305 Asia-Pacific 104,446 — 19,342 123,788 Middle East and Africa 44,959 — — 44,959 Eastern Europe 14,076 — — 14,076 Total Revenues $ 791,533 $ 87,639 $ 224,783 $ 1,103,955 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing and related logistical services $ 673,244 $ — $ — $ 673,244 Applied products 98,966 — — 98,966 Environmental systems for aluminum dross and scrap processing 19,323 — — 19,323 Railway track maintenance equipment — — 102,801 102,801 After market parts and services; safety and diagnostic technology — — 105,101 105,101 Railway contracting services — — 16,881 16,881 Waste processing, recycling, reuse and transportation solutions — 87,639 — 87,639 Total Revenues $ 791,533 $ 87,639 $ 224,783 $ 1,103,955 (a) The Company's acquisition of ESOL closed on April 6, 2020 and the Company's acquisition of Clean Earth closed on June 28, 2019. The results of both are included in the Harsco Clean Earth Segment. The operating results of the former Harsco Industrial Segment have been reflected as discontinued operations in the Company's Condensed Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (b) Revenues are attributed to individual countries based on the location of the facility generating the revenue. (c) Includes Mexico.

Other (Income) Expenses, Net (T

Other (Income) Expenses, Net (Tables)	9 Months Ended
	Sep. 30, 2020
Other Income and Expenses [Abstract]
Schedule of other (income) expenses	The major components of this Condensed Consolidated Statements of Operations caption were as follows: Three Months Ended Nine Months Ended September 30 September 30 (In thousands) 2020 2019 2020 2019 Employee termination benefit costs $ 798 $ 1,591 $ 6,694 $ 5,107 Other costs to exit activities 13 918 478 3,265 Impaired asset write-downs 2 129 75 343 Contingent consideration adjustments 2,437 (906) 2,437 (4,417) Net gains (7) (1,353) (255) (3,624) Other 390 4 (355) (265) Other expenses, net $ 3,633 $ 383 $ 9,074 $ 409

Components of Accumulated Oth_2

Components of Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Schedule of accumulated other comprehensive loss	The components of AOCI, net of the effect of income taxes, and activity for the nine months ended September 30, 2019 and 2020 was as follows: Components of AOCI, Net of Tax (In thousands) Cumulative Foreign Exchange Translation Adjustments Effective Portion of Derivatives Designated as Hedging Instruments Cumulative Unrecognized Actuarial Losses on Pension Obligations Unrealized Gain (Loss) on Marketable Securities Total Balance at December 31, 2018 $ (159,810) $ 1,389 $ (408,655) $ (31) $ (567,107) Adoption of new accounting standard — — (21,429) (a) — (21,429) OCI before reclassifications (20,513) (b) (5,889) (c) 11,630 (b) 19 (14,753) Amounts reclassified from AOCI, net of tax (1,763) 1,404 14,021 — 13,662 Total OCI (22,276) (4,485) 25,651 19 (1,091) OCI attributable to noncontrolling interests 1,868 — — — 1,868 OCI attributable to Harsco Corporation (20,408) (4,485) 25,651 19 777 Balance at September 30, 2019 $ (180,218) $ (3,096) $ (404,433) $ (12) $ (587,759) Components of AOCI, Net of Tax (In thousands) Cumulative Foreign Exchange Translation Adjustments Effective Portion of Derivatives Designated as Hedging Instruments Cumulative Unrecognized Actuarial Losses on Pension Obligations Unrealized Gain (Loss) on Marketable Securities Total Balance at December 31, 2019 $ (143,340) $ (3,717) $ (440,562) $ (3) $ (587,622) OCI before reclassifications (48,150) (b) (2,226) (c) 9,905 (b) (22) (40,493) Amounts reclassified from AOCI, net of tax 12,906 604 18,132 — 31,642 Total OCI (35,244) (1,622) 28,037 (22) (8,851) OCI attributable to noncontrolling interests (579) — — — (579) OCI attributable to Harsco Corporation (35,823) (1,622) 28,037 (22) (9,430) Balance at September 30, 2020 $ (179,163) $ (5,339) $ (412,525) $ (25) $ (597,052) (a) Represents the adoption of the new accounting standard on January 1, 2019 related to stranded tax effects from the Tax Cuts and Jobs Act. (b) Principally foreign currency fluctuation.
Reclassification out of accumulated other comprehensive income	Amounts reclassified from AOCI were as follows: (In thousands) Three Months Ended Nine Months Ended Location on the Condensed Consolidated Statements of Operations September 30 September 30 2020 2019 2020 2019 Recognition of cumulative foreign currency translation adjustments: Gain on substantial liquidation of subsidiaries (d) $ — $ (154) $ 12,906 $ (2,425) Other expenses, net Loss on substantial liquidation of subsidiaries (d) — 662 — 662 Gain on sale of discontinued businesses Amortization of cash flow hedging instruments: Foreign currency exchange forward contracts $ 174 $ (512) $ (1,562) $ (977) Product revenues Foreign currency exchange forward contracts — — — 44 Cost of services sold CCIRs 312 291 912 908 Interest expense Interest rate swaps 739 (76) 1,849 (648) Interest expense Interest rate swaps — — — 2,741 Income from discontinued businesses Total before taxes 1,225 (297) 1,199 2,068 Income taxes (408) (21) (595) (664) Total reclassification of cash flow hedging instruments, net of tax $ 817 $ (318) $ 604 $ 1,404 Amortization of defined benefit pension items (e) : Recognized losses $ 4,962 $ 4,721 $ 14,799 $ 14,761 Defined benefit pension income (expense) Recognized prior service costs 113 61 326 192 Defined benefit pension income (expense) Settlement/curtailment losses — — — 129 Defined benefit pension income (expense) Pension liability transfer - discontinued business — — 5,363 — Gain on sale of discontinued businesses Total before taxes 5,075 4,782 20,488 15,082 Income taxes (323) (340) (2,356) (1,061) Total reclassification of defined benefit pension items, net of tax $ 4,752 $ 4,442 $ 18,132 $ 14,021 (d) No tax impact. (e) These AOCI components are included in the computation of net periodic pension costs. See Note 10, Employee Benefit Plans, for additional details.

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restricted cash	$ 2,283	$ 2,473

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisitions Narrative (Details) - USD ($)	Apr. 06, 2020	Jun. 28, 2019	Jan. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2020
Business Acquisition [Line Items]
Total revenues				$ 509,398,000	$ 423,155,000	$ 1,355,520,000	$ 1,103,955,000
Operating income from continuing operations				5,064,000	46,745,000	9,813,000	84,368,000	$ 84,368,000
Additional interest expense				15,794,000	12,819,000	43,396,000	24,429,000
Receivable with Imputed Interest, Face Amount				40,000,000		40,000,000
Receivables, Fair Value Disclosure			$ 34,300,000	35,600,000		35,600,000			$ 34,300,000
Gain on sale of discontinued business			18,400,000	0	527,980,000	18,371,000	527,980,000
Stericycle
Business Acquisition [Line Items]
Corporate charge					8,600,000	8,900,000	26,500,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Harsco Industrial IKG
Business Acquisition [Line Items]
Selling price									$ 85,000,000
Receivable with Imputed Interest, Face Amount			40,000,000
Disposal Group, Net Gain on Disposal			$ 9,000,000
Discontinued Operations, Held-for-sale | Harsco Industrial
Business Acquisition [Line Items]
Gain on sale of discontinued business				0	527,980,000	18,371,000	527,980,000
Corporate overhead expenses					700,000		3,400,000
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Percentage of interests acquired		100.00%
Cash consideration		$ 628,000,000
Goodwill to be deductible for income tax purposes		16,300,000
Direct acquisition costs					2,000,000		14,500,000
Enterprise valuation		625,000,000
Estimated reimbursements		$ 11,000,000
ESOL
Business Acquisition [Line Items]
Percentage of interests acquired	100.00%
Cash consideration	$ 429,000,000
Goodwill to be deductible for income tax purposes	$ 36,800,000
Total revenues						236,700,000
Operating income from continuing operations						4,700,000
Direct acquisition costs				$ 10,600,000		41,000,000
Clean Earth and ESOL
Business Acquisition [Line Items]
Additional interest expense					$ 5,600,000	$ 4,700,000	$ 34,900,000

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Sep. 30, 2020	Apr. 06, 2020	Dec. 31, 2019	Jun. 28, 2019
Business Acquisition [Line Items]
Goodwill			$ 881,911		$ 738,369
Gross Carrying Amount			517,059		412,657
Noncompete Agreements
Business Acquisition [Line Items]
Gross Carrying Amount			2,500		0
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Cash and cash equivalents			3,600
Trade accounts receivable, net			62,500
Other receivables			2,100
Other current assets			7,300
Property, plant and equipment			77,000
Right-of-use assets			25,800
Goodwill			330,600
Intangible assets			242,200			$ 261,100
Other assets			1,200
Accounts payable			(23,100)
Other current liabilities			(19,700)
Deferred income taxes			45,700
Operating lease liabilities			(19,500)
Total identifiable net assets of Clean Earth			635,700			635,900
Acquisition consideration payable (b)			0
Other liabilities			(8,600)
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Goodwill			474,513		$ 330,230
Measurement Period Adjustments
Intangible assets		$ (18,900)
Total identifiable intangible assets of Clean Earth		200
Harsco Clean Earth Segment | ESOL
Business Acquisition [Line Items]
Cash and cash equivalents			400	$ 400
Trade accounts receivable, net			123,200	124,100
Inventory			5,000	5,000
Other current assets			300	700
Property, plant and equipment			105,300	105,300
Right-of-use assets			56,000	56,000
Goodwill			143,900	152,000
Intangible assets			161,000	161,000
Other assets			200	200
Accounts payable			(49,000)	(48,600)
Accrued expenses			17,500	17,500
Current portion of operating lease liabilities			16,600	16,600
Other current liabilities			(6,400)	(6,400)
Environmental liabilities			24,400	24,400
Deferred income taxes			15,500	15,500
Operating lease liabilities			(39,400)	(39,400)
Total identifiable net assets of Clean Earth			426,500	436,300
Gross Carrying Amount			2,500	2,500
Business Acquisitions, Purchase Price Allocation			$ 429,000	$ 438,800
Measurement Period Adjustments
Cash and cash equivalents	$ 0
Trade accounts receivable	(900)
Inventory	0
Other current assets	(400)
Property, plant and equipment	0
Right-of-use assets	0
Goodwill	(8,100)
Intangible assets	0
Other assets	0
Accounts payable	(400)
Current portion of operating lease liabilities	0
Current portion of operating lease liabilities	0
Other current liabilities	0
Environmental liabilities	0
Deferred income taxes	0
Operating lease liabilities	0
Total identifiable intangible assets of Clean Earth	9,800
Total identifiable net assets of ESOL, including non-compete agreement	(9,800)
Harsco Clean Earth Segment | ESOL | Noncompete Agreements
Measurement Period Adjustments
Intangible assets	$ 0
Harsco Clean Earth Segment | Harsco Clean Earth Segment
Business Acquisition [Line Items]
Cash and cash equivalents						42,800
Trade accounts receivable, net						63,700
Other receivables						800
Other current assets						8,700
Property, plant and equipment						75,600
Right-of-use assets						14,400
Goodwill						313,800
Intangible assets						261,100
Other assets						4,000
Accounts payable						(23,000)
Other current liabilities						(18,000)
Deferred income taxes						51,200
Operating lease liabilities						(11,100)
Acquisition consideration payable (b)						(39,200)
Other liabilities						$ (6,500)
Measurement Period Adjustments
Cash and cash equivalents		(39,200)
Trade accounts receivable		(1,200)
Other current assets		(1,400)
Property, plant and equipment		1,400
Right-of-use assets		11,400
Goodwill		16,800
Intangible assets		(18,900)
Other assets		(2,800)
Accounts payable		(100)
Other current liabilities		(1,700)
Deferred income taxes		5,500
Operating lease liabilities		(8,400)
Other receivables		1,300
Acquisition consideration payable (b)		39,200
Other liabilities		$ (2,100)

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Preliminary Valuation of Identifiable Intangible Assets and Amortization Periods (Details) - USD ($) $ in Thousands	Apr. 06, 2020	Jun. 28, 2019	Jun. 30, 2020	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount					$ 517,059	$ 412,657
Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount					308,559	170,322
Noncompete Agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount					2,500	0
Air rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount					26,139	26,139
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount					31,698	$ 31,719
ESOL | Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	22 years
Preliminary Valuation	$ 138,000				138,000
ESOL | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	10 years
Preliminary Valuation	$ 23,000				23,000
ESOL | Noncompete Agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	4 years
Harsco Clean Earth Segment
Acquired Finite-Lived Intangible Assets [Line Items]
Preliminary Valuation		$ 261,100			242,200
Harsco Clean Earth Segment | Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period		18 years
Preliminary Valuation		$ 176,100			170,100
Harsco Clean Earth Segment | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period		8 years
Preliminary Valuation		$ 33,400			20,500
Harsco Clean Earth Segment | Air rights
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period		27 years
Preliminary Valuation		$ 25,600			25,600
Harsco Clean Earth Segment | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period		12 years
Preliminary Valuation		$ 26,000			26,000
Harsco Clean Earth Segment
Measurement Period Adjustments
Permits and rights				$ (6,000)
Customer relationships				(12,900)
Intangible assets				(18,900)
Air rights				0
Trade names				0
Harsco Clean Earth Segment | ESOL
Acquired Finite-Lived Intangible Assets [Line Items]
Preliminary Valuation	$ 161,000				161,000
Gross Carrying Amount	2,500				2,500
Total identifiable intangible assets acquired	$ 163,500				$ 163,500
Measurement Period Adjustments
Intangible assets			$ 0
Harsco Clean Earth Segment | ESOL | Noncompete Agreements
Measurement Period Adjustments
Permits and rights			0
Customer relationships			0
Intangible assets			0
Total identifiable intangible assets acquired			$ 0
Harsco Clean Earth Segment | Harsco Clean Earth Segment
Acquired Finite-Lived Intangible Assets [Line Items]
Preliminary Valuation		$ 261,100
Measurement Period Adjustments
Intangible assets				$ (18,900)

Acquisitions and Dispositions_4

Acquisitions and Dispositions - Pro Forma Information (Details) - Clean Earth and ESOL - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Pro forma revenues	$ 509.4	$ 572.7	$ 1,486.2	$ 1,650.3
Pro forma net income attributed to Harsco Corporation (including discontinued operations) (e)	$ (1.8)	434.9	$ 1	440.9
Gain on disposition of business		$ 417.5		$ 417.5

Acquisitions and Dispositions_5

Acquisitions and Dispositions - Financial Information Included in Net Income from Discontinued Operations (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Amounts for the former Harsco Industrial Segment:
Gain on sale of discontinued business	$ 18,400	$ 0	$ 527,980	$ 18,371	$ 527,980
Harsco Industrial | Discontinued Operations, Held-for-sale
Amounts for the former Harsco Industrial Segment:
Total revenues		0	39,855	10,203	274,037
Cost of products sold		0	28,174	8,082	201,188
Gain on sale of discontinued business		0	527,980	18,371	527,980
Income (loss) from discontinued business		(716)	803	(593)	24,877
Additional amounts allocated to the former Harsco Industrial Segment:
Selling, general and administrative expenses		521	1,994	1,710	5,521
Interest expense		0	0	0	11,237
Loss on extinguishment of debt		$ 0	$ 5,314	$ 0	$ 5,314

Acquisitions and Dispositions_6

Acquisitions and Dispositions - Condensed Consolidated Statements of Cash Flows (Details) - Harsco Industrial - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Non-cash operating items
Depreciation and amortization	$ 0	$ 3,301
Cash flows from investing activities
Purchases of property, plant and equipment	$ 106	$ 6,151

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($)	Sep. 30, 2020	Jan. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 409,928,000			$ 323,502,000
Accounts Receivable Greater than 12 Months Reserved	1,100,000
Receivable with Imputed Interest, Face Amount	$ 40,000,000
Note Receivable; Interest Rate; Stated percentage	2.50%
Receivables, Fair Value Disclosure	$ 35,600,000	$ 34,300,000	$ 34,300,000
Greater than 12 months
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 5,600,000
Harsco Industrial IKG | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Selling price			$ 85,000,000
Receivable with Imputed Interest, Face Amount		$ 40,000,000

Accounts Receivable - Schedule

Accounts Receivable - Schedule of Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Apr. 06, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 409,928		$ 323,502
Less: Allowance for expected credit losses and doubtful accounts (a) (b)	(8,934)		(13,512)
Trade accounts receivable, net	400,994		309,990
Other receivables	38,325		$ 21,265
ESOL | Harsco Clean Earth Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivables, before allowance for credit losses	136,200
Trade accounts receivable, net	123,200	$ 124,100
Accounts receivable, allowance for credit loss	$ 13,000

Accounts Receivable - Schedul_2

Accounts Receivable - Schedule of Changes in Provisions For Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Receivables [Abstract]
Provision for expected credit losses and doubtful accounts related to trade accounts receivable	$ 861	$ 1,116	$ 1,098	$ 6,539

Accounts Receivable - Schedul_3

Accounts Receivable - Schedule of Fair Value of Notes Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Receivables [Abstract]
Receivable with Imputed Interest, Net Amount	$ 35,389			$ 0
Receivables, Fair Value Disclosure	$ 35,600	$ 34,300	$ 34,300

Inventories (Details)

Inventories (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2016
Revenue from External Customer [Line Items]
Contract estimated forward loss provision for Harsco Rail Segment					$ 1,800,000	$ 45,100,000
Loss provision that exceeds accumulated contract costs	$ 6,600,000		$ 6,600,000
Revenues	509,398,000	$ 423,155,000	1,355,520,000	$ 1,103,955,000
Contract Margin			0
SBB [Member]
Revenue from External Customer [Line Items]
Revenues	$ 11,800,000	$ 5,700,000	$ 29,500,000	$ 16,400,000
Contract 2 [Member] | SBB [Member]
Revenue from External Customer [Line Items]
Percentage complete	65.00%		65.00%

Inventories - Schedule of Inven

Inventories - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Finished goods	$ 14,736	$ 14,550
Work-in-process	13,489	13,088
Raw materials and purchased parts	111,754	104,488
Stores and supplies	30,058	24,865
Total inventories	$ 170,037	$ 156,991

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment
Gross property, plant and equipment	$ 1,895,459	$ 1,806,603
Less: Accumulated depreciation	(1,254,572)	(1,244,817)
Property, plant and equipment, net	640,887	561,786
Land
Property, Plant and Equipment
Gross property, plant and equipment	75,777	30,409
Land improvements
Property, Plant and Equipment
Gross property, plant and equipment	18,748	19,155
Buildings and improvements
Property, Plant and Equipment
Gross property, plant and equipment	225,406	182,795
Machinery and equipment
Property, Plant and Equipment
Gross property, plant and equipment	1,511,120	1,518,652
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 64,408	$ 55,592

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Apr. 06, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating And Finance Leases, Excluding Short Term Leases, Renewal Option	10 years
Weighted average remaining lease term - Operating leases (in years)	8 years 1 month 6 days		11 years 6 months 25 days
Operating And Finance Leases, Excluding Short Term Leases, Termination Option	1 year
Anticipated Lease Commencements	$ 4.6
ESOL | Harsco Clean Earth Segment
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 56	$ 56
Minimum
Lessee, Lease, Description [Line Items]
Operating And Finance Leases, Excluding Short Term Leases, Weighted-Average Remaining Lease Term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating And Finance Leases, Excluding Short Term Leases, Weighted-Average Remaining Lease Term	30 years

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finance leases:
Amortization expense	$ 377	$ 325	$ 1,115	$ 911
Interest on lease liabilities	43	27	139	68
Operating leases	8,558	4,391	21,745	11,518
Variable and short-term lease expense	11,572	6,759	29,169	16,367
Sublease Income	(51)	0	(150)	0
Total lease expense from continuing operations	$ 20,499	$ 11,502	$ 52,018	$ 28,864

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information Related to Leases (Details) - USD ($)	Jun. 28, 2019	Jan. 01, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Cash flows from operating activities - Operating leases			$ 20,512,000	$ 10,881,000
Finance Lease, Interest Payment on Liability			997,000	953,000
ROU assets obtained in exchange for lease obligations:
Operating leases	$ 21,000,000		62,507,000	57,607,000
Finance leases			$ 1,613,000	$ 1,671,000
Harsco Clean Earth Segment
ROU assets obtained in exchange for lease obligations:
Operating leases		$ 34,000,000

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Operating Leases:
Right-of-use assets, net	$ 96,800	$ 52,065
Current portion of operating lease liabilities	26,577	12,544
Operating lease liabilities	67,995	36,974
Finance Leases:
Property, plant and equipment, net	4,179	3,519
Current maturities of long-term debt	1,335	1,237
Long-term debt	$ 2,903	$ 2,218

Leases - Supplemental Additiona

Leases - Supplemental Additional Information (Details)	Sep. 30, 2020	Dec. 31, 2019
Other information:
Weighted average remaining lease term - Operating leases (in years)	8 years 1 month 6 days	11 years 6 months 25 days
Weighted average remaining lease term - Finance leases (in years)	3 years 8 months 23 days	4 years 3 days
Weighted average discount rate - Operating leases	6.10%	6.30%
Weighted average discount rate - Finance leases	4.10%	4.20%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Sep. 30, 2020USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 8,126
Finance Lease, Liability, Payments, Due Next Twelve Months	361
Operating Leases
2021	27,315
2022	20,639
2023	15,818
2024	10,655
After 2024	41,421
Total lease payments	123,974
Less: Imputed interest	(29,402)
Total	94,572
Finance Leases
2021	1,330
2022	1,072
2023	869
2024	702
After 2024	113
Total lease payments	4,447
Less: Imputed interest	(209)
Total	$ 4,238

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Changes in Carrying Amounts of Goodwill by Segment (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Changes in carrying amounts of goodwill
Balance at December 31, 2019	$ 738,369
Goodwill, Other Increase (Decrease)	145,763
Foreign currency translation	(2,221)
Balance at September 30, 2020	881,911
Harsco Environmental Segment
Changes in carrying amounts of goodwill
Balance at December 31, 2019	395,113
Goodwill, Other Increase (Decrease)	1,480
Foreign currency translation	(2,221)
Balance at September 30, 2020	394,372
Harsco Clean Earth Segment
Changes in carrying amounts of goodwill
Balance at December 31, 2019	330,230
Goodwill, Other Increase (Decrease)	144,283
Foreign currency translation	0
Balance at September 30, 2020	474,513
Harsco Rail Segment
Changes in carrying amounts of goodwill
Balance at December 31, 2019	13,026
Goodwill, Other Increase (Decrease)	0
Foreign currency translation	0
Balance at September 30, 2020	$ 13,026

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Intangible Assets, by category
Gross Carrying Amount	$ 517,059		$ 517,059		$ 412,657
Accumulated Amortization	73,377		73,377		113,575
Amortization expense for intangible assets	8,272	$ 5,668	22,542	$ 9,508
Estimated amortization expense for next 5 years
2020	31,200		31,200
2021	32,300		32,300
2022	31,600		31,600
2023	31,600		31,600
2024	31,100		31,100
Customer related
Intangible Assets, by category
Gross Carrying Amount	106,247		106,247		143,996
Accumulated Amortization	43,572		43,572		99,327
Permits
Intangible Assets, by category
Gross Carrying Amount	308,559		308,559		170,322
Accumulated Amortization	14,992		14,992		4,694
Patents
Intangible Assets, by category
Gross Carrying Amount	177		177		249
Accumulated Amortization	126		126		168
Technology related
Intangible Assets, by category
Gross Carrying Amount	37,992		37,992		36,467
Accumulated Amortization	8,187		8,187		5,635
Trade names
Intangible Assets, by category
Gross Carrying Amount	31,698		31,698		31,719
Accumulated Amortization	4,133		4,133		2,182
Air rights
Intangible Assets, by category
Gross Carrying Amount	26,139		26,139		26,139
Accumulated Amortization	827		827		411
Other
Intangible Assets, by category
Gross Carrying Amount	3,747		3,747		3,765
Accumulated Amortization	1,228		1,228		1,158
Noncompete Agreements
Intangible Assets, by category
Gross Carrying Amount	2,500		2,500		$ 0
Accumulated Amortization	$ 312		$ 312

Debt and Credit Agreements - Na

Debt and Credit Agreements - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2019
Debt Instrument [Line Items]
Debt Issuance Costs, Noncurrent, Net		$ 1,900		$ 1,900
Net Debt to Consolidated Adjusted EBITDA Ratio Covenant								4.50
Other Nonoperating Expense		0	$ 158	$ 1,920	$ 7,593
Debt Instrument, Covenant, Increase In Leverage Ratio				0.0025
LIBOR | Minimum
Debt Instrument [Line Items]
Variable rate basis spread	1.50%
LIBOR | Maximum
Debt Instrument [Line Items]
Variable rate basis spread	2.25%
Subsequent Event
Debt Instrument [Line Items]
Net Debt to Consolidated Adjusted EBITDA Ratio Covenant						4.75	5.75
Term Loan 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 280,000		$ 280,000

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined benefit plans:
Multiemployer pension plans	$ 390	$ 527	$ 1,178	$ 1,531
Defined contribution pension plans	2,870	2,358	7,936	8,717
Pension Plan | U.S. Plans
Defined benefit plans:
Service cost	0	10	0	30
Interest cost	1,845	2,637	5,535	7,939
Expected return on plan assets	(2,842)	(2,602)	(8,526)	(7,788)
Recognized prior service costs	0	0	0	0
Recognized loss	1,225	1,395	3,875	4,205
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	0	129
Defined benefit pension plans net periodic pension cost (benefit)	228	1,440	884	4,515
Defined benefit pension plan	453	2,806	2,940	6,296
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	3,100		3,100
Pension Plan | International Plans
Defined benefit plans:
Service cost	448	344	1,303	1,057
Interest cost	4,474	5,168	13,104	16,380
Expected return on plan assets	(10,405)	(8,671)	(30,428)	(27,507)
Recognized prior service costs	113	61	326	192
Recognized loss	3,737	3,326	10,924	10,556
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		0	0	0
Defined benefit pension plans net periodic pension cost (benefit)	(1,633)	228	(4,771)	678
Defined benefit pension plan	2,682	$ 4,121	14,235	$ 16,522
Anticipated contributions to defined benefit pension plans during the remainder of the fiscal year	$ 6,100		$ 6,100

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Income tax expense (benefit)	$ (1,654)	$ 12,601	$ (4,640)	$ 17,814
Unrecognized income tax benefits including interest and penalties	4,000		4,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	300		300
Deferred Tax Assets, Valuation Allowance	2,800		2,800
ESOL
Business Acquisition [Line Items]
Acquisition Costs, Period Cost	8,100		23,900
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Operating Loss Carryforwards	$ 2,800		$ 2,800

Commitments and Contingencies (

Commitments and Contingencies (Details)

Jun. 04, 2018USD ($)

Aug. 31, 2005USD ($)

Sep. 30, 2020USD ($)caseclaimdefendantenforcementAction

Oct. 23, 2020USD ($)

Aug. 21, 2020USD ($)

Apr. 01, 2020USD ($)

Dec. 31, 2019USD ($)

Nov. 01, 2019USD ($)

Nov. 01, 2019BRL (R$)

Jun. 13, 2019USD ($)

Mar. 19, 2019USD ($)

Mar. 19, 2019BRL (R$)

Commitments and Contingencies

Reserve for loss contingencies

$ 7,000,000

Penalties per day

$ 4,000

R$ 25000

$ 900

R$ 5000

Penalties

1,800,000

10,000,000

Current Portion of Environmental Liabilities

6,031,000

$ 3,431,000

Environmental liabilities

29,747,000

5,600,000

Total environmental liabilities

$ 35,778,000

9,031,000

Enforcement Actions | enforcementAction

3

Pennsylvania Department Of Environmental Protection, Processed Slag | Threatened Litigation

Commitments and Contingencies

Loss contingency reserves

$ 400,000

Netherlands

Commitments and Contingencies

Damages sought - interest, penalties and fees

$ 700,000

Allegheny County Health Department [Member]

Commitments and Contingencies

Penalties

$ 6,000

$ 5,000

Damages sought - interest, penalties and fees

100,000

Allegheny County Health Department [Member] | Subsequent Event

Commitments and Contingencies

Penalties

$ 8,000

Brazilian Tax Disputes - Jan 2004 through May 2005 | Sao Paulo State Revenue Authority

Commitments and Contingencies

Damages sought - interest, penalties and fees

15,000,000

Damages sought - principal

1,100,000

Loss contingency, reduced penalty

$ 1,100,000

Amount of damages sought

$ 6,400,000

Brazilian Tax Disputes - Jan 2002 through Dec 2003 | Sao Paulo State Revenue Authority

Commitments and Contingencies

Damages sought - interest, penalties and fees

$ 3,400,000

Damages sought - principal

1,100,000

Loss contingency, reduced penalty

800,000

Amount of damages sought

4,500,000

Loss contingency, reduced penalty, including interest

$ 9,000,000

Brazilian Labor Claims

Commitments and Contingencies

Loss contingency reserves

$ 4,300,000

$ 6,500,000

Other

Commitments and Contingencies

Approximate number of defendants that includes the company named in legal actions | defendant

90

Number of pending claims | claim

17,160

Number of claims dismissed to date by stipulation or summary judgment prior to trial | case

28,300

Other | Active or In Extremis docket

Commitments and Contingencies

Number of pending claims | claim

46

Other | Minimum

Commitments and Contingencies

Amount of damages sought

$ 20,000,000

Other | Maximum

Commitments and Contingencies

Amount of damages sought

$ 25,000,000

Other | New York County as managed by the New York Supreme Court

Commitments and Contingencies

Number of pending claims | case

16,596

Other | New York County as managed by the New York Supreme Court | Pending And Future Litigation, Deferred Or Inactive Docket

Commitments and Contingencies

Number of pending claims | claim

16,550

Other | New York State Supreme Court, Counties Excluding New York County

Commitments and Contingencies

Number of pending claims | case

119

Other | Courts Located In States Other Than New York

Commitments and Contingencies

Number of pending claims | case

445

CSN

Commitments and Contingencies

Penalties per day

$ 18,000

R$ 100000

$ 4,000

R$ 20000

Bahrain Operations, Salt Cake Processing Site [Member]

Commitments and Contingencies

Minority interest

35.00%

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Loss Contingencies by Contingency (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Current Portion of Environmental Liabilities	$ 6,031,000	$ 3,431,000
Long-term environmental liabilities	29,747,000	5,600,000
Total environmental liabilities	$ 35,778,000	$ 9,031,000

Reconciliation of Basic and D_3

Reconciliation of Basic and Diluted Shares - Reconciliation of Basic and Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Income (loss) from continuing operations, net of tax	$ (7,843)	$ 17,831	$ (27,375)	$ 25,453
Weighted-average shares outstanding - basic (in shares)	79,000	79,666	78,916	79,966
Dilutive effect of stock-based compensation (in shares)	0	1,444	0	1,783
Weighted-average shares outstanding - diluted (in shares)	79,000	81,110	78,916	81,749
Earnings (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders:
Basic (in dollars per share)	$ (0.10)	$ 0.22	$ (0.35)	$ 0.32
Diluted (in dollars per share)	$ (0.10)	$ 0.22	$ (0.35)	$ 0.31

Reconciliation of Basic and D_4

Reconciliation of Basic and Diluted Shares - Antidilutive Securities Excluded from Computation of Earnings per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restricted Stock Units (RSUs) [Member]
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	691	0	723	0
Stock appreciation rights
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	2,383	599	2,499	460
Performance share units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	857	265	894	166

Derivative Instruments, Hedgi_3

Derivative Instruments, Hedging Activities and Fair Value - Fair Value of Outstanding Derivative Contracts (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivative contracts
Asset derivatives	$ 2,687	$ 2,985
Liability derivatives	17,484	10,252
Foreign currency exchange forward contracts | Other current assets
Derivative contracts
Asset derivatives	2,687	2,985
Foreign currency exchange forward contracts | Other current liabilities
Derivative contracts
Liability derivatives	9,120	3,873
Interest rate swaps | Other current liabilities
Derivative contracts
Liability derivatives	3,822	2,098
Interest rate swaps | Other liabilities
Derivative contracts
Liability derivatives	4,542	4,281
Fair Value of Derivatives Designated as Hedging Instruments
Derivative contracts
Asset derivatives	2,178	2,039
Liability derivatives	8,651	6,519
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivative contracts
Asset derivatives	2,178	2,039
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivative contracts
Liability derivatives	287	140
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other current liabilities
Derivative contracts
Liability derivatives	3,822	2,098
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivative contracts
Liability derivatives	4,542	4,281
Fair Value of Derivatives Not Designated as Hedging Instruments
Derivative contracts
Asset derivatives	509	946
Liability derivatives	8,833	3,733
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivative contracts
Asset derivatives	509	946
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivative contracts
Liability derivatives	8,833	3,733
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other current liabilities
Derivative contracts
Liability derivatives	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivative contracts
Liability derivatives	$ 0	$ 0

Derivative Instruments, Hedgi_4

Derivative Instruments, Hedging Activities and Fair Value - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2022	Dec. 31, 2019	Feb. 28, 2018
Foreign Currency Derivatives
Liabilities		$ 2,179,075,000		$ 2,179,075,000			$ 1,577,808,000
Pre-tax net gains (losses) on certain loans designated as hedges of net investments in foreign subsidiaries		4,600,000	$ (3,000,000)	(7,400,000)	$ (3,700,000)
Amount of gain or (loss) reclassified from accumulated other comprehensive income into income		1,225,000		1,199,000
Long-term debt		1,264,600,000		1,264,600,000			827,200,000
Foreign currency exchange forward contracts
Foreign Currency Derivatives
Derivative, Notional Amount		431,600,000		431,600,000			496,300,000
Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Principal amount		200,000,000		$ 200,000,000				$ 300,000,000
LIBOR | Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Variable rate basis spread				2.45%
LIBOR | Forecast | Term Loan Facility, Fixed-Rate | Term Loan
Foreign Currency Derivatives
Variable rate basis spread						3.12%
Floating-Rate To Fixed-Rate
Foreign Currency Derivatives
Converted debt	$ 100,000,000
Reported Value Measurement
Foreign Currency Derivatives
Long-term debt		$ 1,265,700,000		$ 1,265,700,000			$ 795,000,000

Derivative Instruments, Hedgi_5

Derivative Instruments, Hedging Activities and Fair Value - Effect of Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Effect of derivative instruments
Amount Recognized in OCI on Derivatives	$ (1,363)		$ (2,962)
Amount Recognized in OCI on Derivatives		$ (71)		$ (7,748)
Amount Reclassified from AOCI into Income - Effective Portion or Equity	1,225		1,199
Amount Reclassified from AOCI into Income - Effective Portion or Equity		(297)		2,068
Foreign currency exchange forward contracts
Effect of derivative instruments
Amount Recognized in OCI on Derivatives	(1,244)		834
Amount Recognized in OCI on Derivatives		808		765
Foreign currency exchange forward contracts | Cost of services and products sold
Effect of derivative instruments
Amount Reclassified from AOCI into Income - Effective Portion or Equity	174		(1,562)
Amount Reclassified from AOCI into Income - Effective Portion or Equity		(512)		(933)
Interest rate swaps | Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Effect of derivative instruments
Income (loss) from discontinued business	0	0	0	2,741
Interest rate swaps | Interest Expense
Effect of derivative instruments
Amount Reclassified from AOCI into Income - Effective Portion or Equity	739		1,849
Amount Reclassified from AOCI into Income - Effective Portion or Equity		(76)		(648)
Interest rate swaps
Effect of derivative instruments
Amount Recognized in OCI on Derivatives	(95)		(3,835)
Amount Recognized in OCI on Derivatives		(930)		(8,566)
Cross currency interest rate swaps
Effect of derivative instruments
Amount Recognized in OCI on Derivatives	(24)		39
Amount Recognized in OCI on Derivatives		51		53
Cross currency interest rate swaps | Interest Expense
Effect of derivative instruments
Amount Reclassified from AOCI into Income - Effective Portion or Equity	$ 312		$ 912
Amount Reclassified from AOCI into Income - Effective Portion or Equity		$ 291		$ 908

Derivative Instruments, Hedgi_6

Derivative Instruments, Hedging Activities and Fair Value - Derivatives Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Product Revenues	$ 509,398	$ 423,155	$ 1,355,520	$ 1,103,955
Interest Expense	(15,794)	(12,819)	(43,396)	(24,429)
Gain or (loss) reclassified from AOCI into income	(1,225)		(1,199)
Interest rate swaps | Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Derivative [Line Items]
Interest Expense	(739)	76	(1,849)	648
Income (loss) from discontinued business	0	0	0	(2,741)
Cross-currency interest rate swaps | Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Derivative [Line Items]
Interest Expense	(312)	(291)	(912)	(908)
Foreign currency exchange forward contracts | Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Derivative [Line Items]
Cost of services sold	0	0	0	44
Product Revenues | Interest rate swaps
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	0
Gain or (loss) reclassified from AOCI into income		0
Product Revenues | Foreign exchange contracts
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	(174)		1,562
Gain or (loss) reclassified from AOCI into income		(512)		977
Amount excluded from effectiveness testing recognized in earnings	12		208
Amount excluded from effectiveness testing recognized in earnings		86		403
Derivative Instruments, Loss Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing	3		24
Product Revenues | Cross-currency interest rate swaps
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	0
Gain or (loss) reclassified from AOCI into income		0
Interest Expense | Interest rate swaps
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	(739)		(1,849)
Gain or (loss) reclassified from AOCI into income		(76)		(648)
Interest Expense | Foreign exchange contracts
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	0
Gain or (loss) reclassified from AOCI into income		0
Amount excluded from effectiveness testing recognized in earnings	0
Amount excluded from effectiveness testing recognized in earnings		0
Interest Expense | Cross-currency interest rate swaps
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	(312)		(912)
Gain or (loss) reclassified from AOCI into income	312	291		908
Cost of services and products sold | Foreign currency exchange forward contracts
Derivative [Line Items]
Gain or (loss) reclassified from AOCI into income	(174)		1,562
Amount of Gain Recognized in Income on Derivatives	(12,279)	10,642	(5,001)	15,735
Product Revenues
Derivative [Line Items]
Product Revenues	125,119	106,488	334,324	319,765
Cost of services sold	99,043	71,970	257,512	220,634
Products And Services, Service Revenue
Derivative [Line Items]
Product Revenues	384,279	316,667	1,021,196	784,190
Cost of services sold	$ 313,136	239,519	$ 835,277	608,230
Gain or (loss) reclassified from AOCI into income		$ 0		$ (44)

Review of Operations by Segme_3

Review of Operations by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Operations by segment
Revenues	$ 509,398	$ 423,155	$ 1,355,520	$ 1,103,955
Operating income from continuing operations	5,064	46,745	9,813	84,368	$ 84,368
Interest income	604	445	1,613	1,569
Interest expense	(15,794)	(12,819)	(43,396)	(24,429)
Unused debt commitment and amendment fees	0	(158)	(1,920)	(7,593)
Defined benefit pension income (expense)	(1,859)	1,356	(5,171)	4,166
Income (loss) from continuing operations before income taxes and equity income	(8,267)	32,857	(28,719)	49,749
Capital Expenditures	27,883	54,941	78,990	140,920
Depreciation	32,353	29,824	93,864	89,681
Depreciation Excluding Industrial Segment			93,656	86,941
Amortization			24,721	11,941
Amortization Excluding Deferred Financing Costs	9,049	6,150	24,721	11,380
Operating Segments
Operations by segment
Operating income from continuing operations	25,278	56,217	68,507	123,123
Corporate
Operations by segment
Operating income from continuing operations	(20,214)	(9,472)	(58,694)	(38,755)
Capital Expenditures	62	109	444	1,549
Depreciation	497	716	1,531	2,094
Amortization	776	481	2,179	1,872
Harsco Environmental Segment | Operating Segments
Operations by segment
Revenues	222,507	260,883	668,057	791,533
Operating income from continuing operations	12,317	32,794	36,400	84,868
Capital Expenditures	21,700	48,348	65,102	122,606
Depreciation	25,588	25,557	75,626	79,074
Amortization	1,970	1,751	5,827	5,436
Harsco Clean Earth Segment | Operating Segments
Operations by segment
Revenues	194,098	87,639	434,489	87,639
Operating income from continuing operations	8,902	11,308	12,945	11,308
Capital Expenditures	2,647	3,204	7,134	3,204
Depreciation	5,010	2,359	12,769	2,359
Amortization	6,218	3,834	16,463	3,834
Harsco Rail Segment | Operating Segments
Operations by segment
Revenues	92,793	74,633	252,974	224,783
Operating income from continuing operations	4,059	12,115	19,162	26,947
Capital Expenditures	3,474	3,280	6,310	13,561
Depreciation	1,258	1,192	3,730	3,414
Amortization	$ 85	$ 84	$ 252	$ 238

Revenue Recognition - Revenues

Revenue Recognition - Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 509,398	$ 423,155	$ 1,355,520	$ 1,103,955
Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	194,098	87,639	434,489	87,639
Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	181,640	218,788	563,159	673,244
Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	38,166	34,890	95,019	98,966
Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	2,701	7,205	9,879	19,323
Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	55,493	30,233	138,519	102,801
After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	29,100	37,100	92,800	105,101
Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	8,200	7,300	21,655	16,881
North America
Disaggregation of Revenue [Line Items]
Total revenues	315,876	222,638	793,738	489,742
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	113,922	103,835	328,230	321,085
Latin America
Disaggregation of Revenue [Line Items]
Total revenues	29,497	35,678	89,045	110,305
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	30,239	41,279	85,877	123,788
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	15,558	15,302	46,240	44,959
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,306	4,423	12,390	14,076
Operating Segments | Harsco Environmental Segment
Disaggregation of Revenue [Line Items]
Total revenues	222,507	260,883	668,057	791,533
Operating Segments | Harsco Environmental Segment | Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	181,640	218,788	563,159	673,244
Operating Segments | Harsco Environmental Segment | Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	38,166	34,890	95,019	98,966
Operating Segments | Harsco Environmental Segment | Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	2,701	7,205	9,879	19,323
Operating Segments | Harsco Environmental Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Environmental Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	58,973	78,076	186,210	229,537
Operating Segments | Harsco Environmental Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	92,506	93,426	271,795	290,125
Operating Segments | Harsco Environmental Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	29,085	35,127	87,453	108,390
Operating Segments | Harsco Environmental Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	22,079	34,529	63,969	104,446
Operating Segments | Harsco Environmental Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	15,558	15,302	46,240	44,959
Operating Segments | Harsco Environmental Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	4,306	4,423	12,390	14,076
Operating Segments | Harsco Clean Earth Segment
Disaggregation of Revenue [Line Items]
Total revenues	194,098	87,639	434,489	87,639
Operating Segments | Harsco Clean Earth Segment | Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	194,098	87,639	434,489	87,639
Operating Segments | Harsco Clean Earth Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	194,098	87,639	434,489	87,639
Operating Segments | Harsco Clean Earth Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Clean Earth Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment
Disaggregation of Revenue [Line Items]
Total revenues	92,793	74,633	252,974	224,783
Operating Segments | Harsco Rail Segment | Waste Processing and Reuse Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Environmental services related to resource recovery for metals manufacturing and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Applied Products
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Aluminum Dross and Scrap Processing Systems
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Railway Track Maintenance Equipment
Disaggregation of Revenue [Line Items]
Total revenues	55,493	30,233	138,519	102,801
Operating Segments | Harsco Rail Segment | After-market Parts and Services; Safety and Diagnostic Technology
Disaggregation of Revenue [Line Items]
Total revenues	29,100	37,100	92,800	105,101
Operating Segments | Harsco Rail Segment | Railway Contracting Services
Disaggregation of Revenue [Line Items]
Total revenues	8,200	7,300	21,655	16,881
Operating Segments | Harsco Rail Segment | North America
Disaggregation of Revenue [Line Items]
Total revenues	62,805	56,923	173,039	172,566
Operating Segments | Harsco Rail Segment | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues	21,416	10,409	56,435	30,960
Operating Segments | Harsco Rail Segment | Latin America
Disaggregation of Revenue [Line Items]
Total revenues	412	551	1,592	1,915
Operating Segments | Harsco Rail Segment | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues	8,160	6,750	21,908	19,342
Operating Segments | Harsco Rail Segment | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Harsco Rail Segment | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Total contract assets	$ 57.6		$ 57.6		$ 31.2
Total advances on contracts	86		86		$ 60.3
Revenue recognized	20	$ 17	55	$ 53
Disaggregation of Revenue [Line Items]
Contract with Customer, Liability, Revenue Recognized	20	$ 17	$ 55	$ 53
Harsco Rail Segment
Revenue from Contract with Customer [Abstract]
Revenue recognized	0.8
Disaggregation of Revenue [Line Items]
Contract with Customer, Liability, Revenue Recognized	$ 0.8

Revenue Recognition - Remaining

Revenue Recognition - Remaining Performance Obligation (Details) - USD ($) $ in Millions	Sep. 30, 2020	Mar. 31, 2020
Harsco Environmental Segment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 102.5
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	30.1
Period of expected timing of satisfaction		1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	20.1
Period of expected timing of satisfaction		1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	15.8
Period of expected timing of satisfaction		1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	13.2
Period of expected timing of satisfaction		1 year
Harsco Environmental Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period of expected timing of satisfaction		1 year
Harsco Rail Segment
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	364
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	133
Period of expected timing of satisfaction		1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	131.5
Period of expected timing of satisfaction		1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	64
Period of expected timing of satisfaction		1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 30.8
Period of expected timing of satisfaction		1 year
Harsco Rail Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period of expected timing of satisfaction		1 year

Other (Income) Expenses, Net (D

Other (Income) Expenses, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Income and Expenses [Abstract]
Employee termination benefit costs	$ 798	$ 1,591	$ 6,694	$ 5,107
Net gains	(7)	(1,353)	(255)	(3,624)
Other costs to exit activities	13	918	478	3,265
Impaired asset write-downs	2	129	75	343
Contingent consideration adjustments	2,437	(906)	2,437	(4,417)
Other	390	4	(355)	(265)
Other expenses, net	$ 3,633	$ 383	$ 9,074	$ 409

Components of Accumulated Oth_3

Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 01, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adoption of new accounting standard									$ 0
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 764,516	$ 758,870	$ 789,659	$ 349,114	$ 335,272	$ 313,376	$ 789,659	$ 313,376
Other comprehensive income (loss) before reclassifications							(40,493)	(14,753)
Amounts reclassified from accumulated other comprehensive loss							31,642	13,662
Total other comprehensive income (loss)	8,120	13,031	(30,002)	(9,220)	3,598	4,531	(8,851)	(1,091)
OCI attributable to noncontrolling interests							(579)	1,868
Other comprehensive income (loss) attributable to Harsco Corporation							(9,430)	777
Ending balance	766,414	764,516	758,870	751,260	349,114	335,272	766,414	751,260
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			(143,340)			(159,810)	(143,340)	(159,810)
Other comprehensive income (loss) before reclassifications							(48,150)	(20,513)
Amounts reclassified from accumulated other comprehensive loss							12,906	(1,763)
Total other comprehensive income (loss)							(35,244)	(22,276)
OCI attributable to noncontrolling interests							(579)	1,868
Other comprehensive income (loss) attributable to Harsco Corporation							(35,823)	(20,408)
Ending balance	(179,163)			(180,218)			(179,163)	(180,218)
Effective Portion of Deriviatives Designated as Hedging Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adoption of new accounting standard									0
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			(3,717)			1,389	(3,717)	1,389
Other comprehensive income (loss) before reclassifications							(2,226)	(5,889)
Amounts reclassified from accumulated other comprehensive loss							604	1,404
Total other comprehensive income (loss)							(1,622)	(4,485)
OCI attributable to noncontrolling interests							0	0
Other comprehensive income (loss) attributable to Harsco Corporation							(1,622)	(4,485)
Ending balance	(5,339)			(3,096)			(5,339)	(3,096)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adoption of new accounting standard									(21,429)
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			(440,562)			(408,655)	(440,562)	(408,655)
Other comprehensive income (loss) before reclassifications							9,905	11,630
Amounts reclassified from accumulated other comprehensive loss							18,132	14,021
Total other comprehensive income (loss)							28,037	25,651
OCI attributable to noncontrolling interests							0	0
Other comprehensive income (loss) attributable to Harsco Corporation							28,037	25,651
Ending balance	(412,525)			(404,433)			(412,525)	(404,433)
Unrealized Loss on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			(3)			(31)	(3)	(31)
Other comprehensive income (loss) before reclassifications							(22)	19
Amounts reclassified from accumulated other comprehensive loss							0	0
Total other comprehensive income (loss)							(22)	19
OCI attributable to noncontrolling interests							0	0
Other comprehensive income (loss) attributable to Harsco Corporation							(22)	19
Ending balance	(25)			(12)			(25)	(12)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adoption of new accounting standard									$ (21,429)
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(603,618)	(616,476)	(587,622)	(580,229)	(584,425)	(567,107)	(587,622)	(567,107)
Total other comprehensive income (loss)	6,566	12,858	(28,854)	(7,530)	4,196	4,111
Ending balance	$ (597,052)	$ (603,618)	$ (616,476)	$ (587,759)	$ (580,229)	$ (584,425)	$ (597,052)	$ (587,759)

Components of Accumulated Oth_4

Components of Accumulated Other Comprehensive Loss - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net	$ (3,633)			$ (383)			$ (9,074)	$ (409)
Product revenues	509,398			423,155			1,355,520	1,103,955
Interest expense	15,794			12,819			43,396	24,429
Income from continuing operations before income taxes	(8,267)			32,857			(28,719)	49,749
Income tax expense (benefit)	(1,654)			12,601			(4,640)	17,814
Net income (loss)	(8,339)	$ (9,455)	$ 1,227	437,857	$ 10,929	$ 22,537	(16,567)	471,323
Amount Reclassified from Accumulated Other Comprehensive Loss | Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net	0
Amount Reclassified from Accumulated Other Comprehensive Loss | Cumulative Unrecognized Actuarial Losses on Pension Obligations
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	5,075			4,782			20,488	15,082
Income tax expense (benefit)	(323)			(340)			(2,356)	(1,061)
Net income (loss)	4,752			4,442			18,132	14,021
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	1,225			(297)			1,199	2,068
Income tax expense (benefit)	(408)			(21)			(595)	(664)
Net income (loss)	817			(318)			604	1,404
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Foreign currency exchange forward contracts
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net				(154)			12,906	(2,425)
Discontinued Operation, Gain From Disposal Of Discontinued Operation, Before Income Tax	0			662			0	662
Product revenues	174			(512)			(1,562)	(977)
Cost of services sold	0			0			0	44
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Cross currency interest rate swaps
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	312			291			912	908
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Interest rate swaps
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	739			(76)			1,849	(648)
Income (loss) from discontinued business	0			0			0	2,741
Amount Reclassified from Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	4,962			4,721			14,799	14,761
Amount Reclassified from Accumulated Other Comprehensive Loss | Prior service costs (benefits)
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	0			0				0
Amount Reclassified from Accumulated Other Comprehensive Loss | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	113			61			326	192
Amount Reclassified from Accumulated Other Comprehensive Loss | AOCI Attributable to Parent
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	$ 0			$ 0			0	$ 129
Amount Reclassified from Accumulated Other Comprehensive Loss | Pension Liability Transfer - Discontinued Businesses
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)							$ 5,363

Uncategorized Items - hsc-20200

Label	Element	Value
Retained Earnings [Member]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1	$ 21,429,000