Enviri (NVRI) 10-K 24 Feb 22 2021 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
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
Title of 12(b) Security	Common stock, par value $1.25 per share
Trading Symbol	HSC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,617,067,000
Entity Common Stock, Shares Outstanding		79,225,394
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0000045876
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Selected portions of the 2022 Proxy Statement are incorporated by reference into Part III of this Report.

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Philadelphia, Pennsylvania
Auditor Firm ID	238

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 82,908	$ 76,454
Restricted cash	4,220	3,215
Trade accounts receivable, net	377,881	355,313
Other receivables	33,059	31,208
Inventories	70,493	61,001
Prepaid Expense	31,065	30,645
Current portion of assets held-for-sale	265,413	247,477
Other current assets	9,934	10,510
Total current assets	874,973	815,823
Property, plant and equipment, net	653,913	630,354
Right-of-use assets, net	101,576	92,495
Goodwill	883,109	889,048
Intangible assets, net	402,801	435,116
Deferred income tax assets	17,883	10,368
Assets held-for-sale	71,234	69,906
Other assets	48,419	50,177
Total assets	3,053,908	2,993,287
Current liabilities:
Short-term borrowings	7,748	7,450
Current maturities of long-term debt	10,226	13,576
Accounts payable	186,126	164,102
Accrued compensation	48,165	44,382
Income taxes payable	6,378	3,403
Operating Lease, Liability, Current	25,590	23,117
Total Rail liabilities included in Liabilities of assets held-for-sale	161,999	127,927
Other current liabilities	155,159	153,998
Total current liabilities	601,391	537,955
Long-term debt	1,359,446	1,271,189
Retirement plan liabilities	93,693	231,335
Operating Lease, Liability, Noncurrent	74,571	67,126
Liabilities of assets held-for-sale	8,492	52,851
Accrued Environmental Loss Contingencies, Noncurrent	28,435	29,424
Deferred tax liabilities	33,826	36,192
Other liabilities	48,284	53,816
Total liabilities	2,248,138	2,279,888
COMMITMENTS AND CONTINGENCIES
HARSCO CORPORATION STOCKHOLDERS' EQUITY
Common stock, par value $1.25 (issued 115,906,393 and 115,430,042 shares at December 31, 2021 and 2020, respectively)	144,883	144,288
Additional paid-in capital	215,528	204,078
Accumulated other comprehensive loss	(560,139)	(645,741)
Retained earnings	1,794,510	1,797,759
Treasury stock, at cost (36,690,847 and 36,505,672 shares at December 31, 2021 and 2020, respectively)	(846,622)	(843,230)
Total Harsco Corporation stockholders' equity	748,160	657,154
Noncontrolling interests	57,610	56,245
Total equity	805,770	713,399
Total liabilities and equity	$ 3,053,908	$ 2,993,287

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 1.25	$ 1.25
Common stock, shares issued	115,906,393	115,430,042	114,720,347	113,473,951
Treasury stock, shares	36,690,847	36,505,672	36,205,589	33,928,928

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from continuing operations:
Product revenues	$ 1,848,399	$ 1,534,033	$ 1,204,369
Costs and expenses from continuing operations:
Selling, general and administrative costs	272,233	284,442	205,177
Research and development expenses	956	534	886
Other expenses	(3,722)	10,072	(8,194)
Total costs and expenses	1,760,023	1,537,339	1,127,966
Operating income (loss) from continuing operations	88,376	(3,306)	76,403
Interest income	2,231	2,129	1,946
Interest expense	(63,235)	(58,196)	(34,024)
Defined benefit pension income (expense)	15,640	7,073	(5,556)
Loss on early extinguishment of debt	(5,506)	(1,920)	(7,704)
Income (loss) from continuing operations before income taxes and equity income	37,506	(54,220)	31,065
Income tax expense	(9,089)	8,673	(12,728)
Equity in income (loss) of unconsolidated entities, net	(302)	186	273
Income (loss) from continuing operations	28,115	(45,361)	18,610
Discontinued operations:
Income (loss) from discontinued businesses	0	18,281	569,135
Income (loss) from discontinued businesses	(25,863)	20,350	52,937
Income tax benefit (expense) from discontinued businesses	477	(15,245)	(128,464)
Income (loss) from discontinued operations, net of tax	(25,386)	23,386	493,608
Net income (loss)	2,729	(21,975)	512,218
Less: Net income attributable to noncontrolling interests	(5,978)	(4,366)	(8,299)
Net income (loss) attributable to Harsco Corporation	(3,249)	(26,341)	503,919
Amounts attributable to Harsco Corporation common stockholders:
Income (loss) from continuing operations, net of tax	22,137	(49,727)	10,311
Income (loss) from discontinued operations, net of tax	(25,386)	23,386	493,608
Net income (loss) attributable to Harsco Corporation common stockholders	$ (3,249)	$ (26,341)	$ 503,919
Weighted average shares of common stock outstanding	79,234	78,939	79,632
Basic earnings (loss) per share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.28	$ (0.63)	$ 0.13
Discontinued operations (in dollars per share)	(0.32)	0.30	6.20
Basic earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ (0.04)	$ (0.33)	$ 6.33
Diluted weighted average shares of stock outstanding	80,289	78,939	81,375
Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders:
Continuing operations (in dollars per share)	$ 0.28	$ (0.63)	$ 0.13
Discontinued operations (in dollars per share)	(0.32)	0.30	6.07
Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders (in dollars per share)	$ (0.04)	$ (0.33)	$ 6.19	[1]
Services
Revenues from continuing operations:
Product revenues	$ 1,700,896	$ 1,400,648	$ 1,058,373
Costs and expenses from continuing operations:
Cost of services and products sold	1,369,073	1,140,303	822,043
Product
Revenues from continuing operations:
Product revenues	147,503	133,385	145,996
Costs and expenses from continuing operations:
Cost of services and products sold	$ 121,483	$ 101,988	$ 108,054
[1]	Does not total due to rounding.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,729	$ (21,975)	$ 512,218
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes of $1,284, 2,507 and $(2,167) in 2020, 2019 and 2018, respectively	(10,994)	20,760	15,498
Net gain (loss) on cash flow hedging instruments, net of deferred income taxes of $(797), $79 and $1,438 in 2021, 2020 and 2019, respectively	2,816	(2,123)	(5,106)
Pension liability adjustments, net of deferred income taxes of $(5,409), $384 and $(3,244) in 2021, 2020 and 2019, respectively	92,252	(73,938)	(10,478)
Unrealized gain (loss) on marketable securities, net of deferred income taxes of $(12), $2 and $(11) in 2021, 2020 and 2019, respectively	31	(6)	28
Total OCI	84,105	(55,307)	(58)
Total comprehensive income (loss)	86,834	(77,282)	512,160
Less: Comprehensive income attributable to noncontrolling interests	(4,480)	(7,178)	(7,327)
Comprehensive income (loss) attributable to Harsco Corporation	$ 82,354	$ (84,460)	$ 504,833

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, deferred income taxes	$ (23)	$ 1,284	$ 2,507
Net gains (losses) on cash flow hedging instruments, deferred income taxes	(797)	79	1,438
Pension liability adjustments, deferred income taxes	(5,409)	384	(3,244)
Unrealized gain (loss) on marketable securities, deferred income taxes	$ (12)	$ 2	$ (11)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 2,729	$ (21,975)	$ 512,218
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation	131,449	125,765	119,803
Amortization	35,224	33,937	18,592
Loss on early extinguishment of debt	2,668	0	5,314
Deferred income tax expense (benefit)	(16,930)	1,115	6,815
Equity (income) loss of unconsolidated entities, net	302	(186)	(273)
Dividends from unconsolidated entities	269	216	125
Gain on sale from discontinued businesses	0	(18,281)	(569,135)
Other, net	2,062	310	1,764
Changes in assets and liabilities:
Accounts receivable	(19,781)	34,221	(3,464)
Income tax refunds receivable from acquisition, reimbursable to seller	2,870	(11,032)	0
Insurance receivable	0	0	195,000
Inventories	(7,783)	(12,281)	(42,484)
Contract assets	(43,510)	(28,376)	(21,795)
Right-of-use-assets	28,300	25,400	15,164
Accounts payable	14,118	(14,452)	13,407
Accrued interest payable	(411)	(2,422)	14,723
Accrued compensation	6,469	2,921	(15,759)
Advances on contracts and other customer advances	(14,311)	10,492	(4,172)
Operating lease liabilities	(27,307)	(24,785)	(14,740)
Insurance liability	0	0	(195,000)
Income taxes payable - gain on sale of discontinued businesses	0	(12,373)	12,373
Retirement plan liabilities, net	(45,786)	(33,257)	(24,022)
Other assets and liabilities	21,556	(1,139)	(24,617)
Net cash provided (used) by operating activities	72,197	53,818	(163)
Cash flows from investing activities:
Purchases of property, plant and equipment	(158,326)	(120,224)	(184,973)
Proceeds from sale of businesses	0	37,219	658,414
Purchase of businesses, net of cash acquired*	0	(432,855)	(623,495)
Proceeds from sales of assets	16,724	6,204	17,022
Expenditures for intangible assets	(358)	(317)	(1,311)
Proceeds from notes receivable	6,400	0
Purchase of equity method investment	0	0	(2,364)
Payments for interest rate swap terminations	0	0	(2,758)
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	10,940	(10,519)	7,273
Other investing activities, net	171	(152)	0
Net cash used by investing activities	(124,449)	(520,644)	(132,192)
Cash flows from financing activities:
Short-term borrowings, net	935	1,612	(5,398)
Current maturities and long-term debt:
Additions	540,663	638,717	848,314
Reductions	(464,848)	(139,887)	(661,620)
Dividends paid to noncontrolling interests	(3,103)	(2,978)	(4,712)
Noncontrolling Interest - purchase or sale	0	(561)	4,026
Stock-based compensation - Employee taxes paid	(3,392)	(4,303)	(11,234)
Common stock acquired for treasury	0	0	(31,838)
Payment of contingent consideration	(1,588)	(2,342)	0
Deferred financing costs	(7,828)	(1,928)	(11,272)
Other financing activities, net	(601)	(1,372)	(532)
Net cash provided by financing activities	60,238	486,958	125,734
Effect of exchange rate changes on cash, including restricted cash	(527)	(195)	(793)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	7,459	19,937	(7,414)
Cash and cash equivalents, including restricted cash, at beginning of period	79,669	59,732	67,146
Cash and cash equivalents, including restricted cash, at end of period	87,128	79,669	59,732
Supplemental Cash Flow Information [Abstract]
Change in accrual for purchases of property, plant and equipment included in accounts payable	4,253	3,559	5,164
Purchase of businesses, net of cash acquired
Working capital	532	(33,387)	(26,663)
Property, plant and equipment	823	(102,258)	(77,295)
Goodwill	(1,232)	(153,562)	(330,230)
Long-term debt acquired	0	0	605
Other noncurrent assets and liabilities, net	(123)	(143,648)	(189,912)
Net cash used to acquire businesses	$ 0	$ (432,855)	$ (623,495)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock Issued	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests
Balances at Dec. 31, 2018	$ 313,376	$ 0	$ 141,842	$ (795,821)	$ 190,597	$ 1,298,752	$ 21,429	$ (567,107)	$ (21,429)	$ 45,113
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	512,218					503,919				8,299
Cash dividends declared:
Noncontrolling interests	(4,693)									(4,693)
Total other comprehensive income (loss)	(58)							914		(972)
Sale of investment in consolidated subsidiary	4,026									4,026
Strategic venture exit	(3,694)									(3,694)
Stock appreciation rights exercised	(117)		20	(117)	(20)
Vesting of restricted stock units and other stock grants	(2,882)		402	(2,882)	(402)
Vesting of performance share units	(8,248)		1,136	(8,235)	(1,149)
Treasury shares repurchased	(31,838)			(31,838)
Amortization of unearned stock-based compensation, net of forfeitures	11,569				11,569
Balances at Dec. 31, 2019	789,659		143,400	(838,893)	200,595	1,824,100		(587,622)		48,079
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(21,975)					(26,341)				4,366
Cash dividends declared:
Noncontrolling interests	(2,978)									(2,978)
Total other comprehensive income (loss)	(55,307)							(58,119)		2,812
Purchase of noncontrolling interest	(561)				(4,527)					3,966
Stock appreciation rights exercised	(24)		11	(24)	(11)
Vesting of restricted stock units and other stock grants	(1,108)		288	(1,108)	(288)
Vesting of performance share units	(3,205)		589	(3,205)	(589)
Amortization of unearned stock-based compensation, net of forfeitures	8,898				8,898
Balances at Dec. 31, 2020	713,399		144,288	(843,230)	204,078	1,797,759		(645,741)		56,245
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,729					(3,249)				5,978
Cash dividends declared:
Noncontrolling interests	(3,116)									(3,116)
Total other comprehensive income (loss)	84,105							85,602		(1,497)
Stock appreciation rights exercised	(376)		58	(376)	(58)
Vesting of restricted stock units and other stock grants	(1,983)		382	(1,983)	(382)
Vesting of performance share units	(1,033)		155	(1,033)	(155)
Amortization of unearned stock-based compensation, net of forfeitures	12,045				12,045
Balances at Dec. 31, 2021	$ 805,770		$ 144,883	$ (846,622)	$ 215,528	$ 1,794,510		$ (560,139)		$ 57,610

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred income taxes	$ (6,241)	$ 1,749	$ 690
Stock appreciation rights exercised (in shares)	28,789	6,236	11,246
Vesting of restricted stock units (in shares)	193,260	138,225	196,102
Vesting of performance shares (in shares)	69,127	265,151	529,213
Treasury shares repurchased (in shares)			1,766,826
Treasury Stock
Treasury shares repurchased (in shares)			1,766,826

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Consolidation The consolidated financial statements include all accounts of Harsco Corporation (the "Company"), all entities in which the Company has a controlling voting interest and variable interest entities required to be consolidated in accordance with U.S. GAAP. Intercompany accounts and transactions have been eliminated among consolidated entities. The Company's management has evaluated all activity of the Company and concluded that subsequent events are properly reflected in the Company's consolidated financial statements and notes as required by U.S. GAAP. Reclassifications Certain reclassifications have been made to prior year amounts to conform with current year classifications. Cash and Cash Equivalents Cash and cash equivalents include cash on hand, demand deposits and short-term investments that are highly liquid in nature and have an original maturity of three months or less. Restricted Cash The Company had restricted cash of $4.2 million and $3.2 million at December 31, 2021 and 2020, respectively, and the restrictions are primarily related to collateral provided for certain guarantees of the Company’s performance. Accounts 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. Inventories Inventories are accounted for using the average cost, first-in, first-out ("FIFO"), or last-in, first-out ("LIFO") method. Inventory accounted for under the average cost and FIFO methods are stated at the lower of cost or net realizable value. Inventory accounted for under the LIFO method is stated at the lower of cost or market. See Note 5, Inventories, for additional information. Depreciation Property, plant and equipment is recorded at cost and depreciated over the estimated useful lives of the assets using, principally, the straight-line method. When property, plant and equipment is retired from service, the cost of the retirement is charged to the allowance for depreciation to the extent of the accumulated depreciation and the balance is charged to income. Long-lived assets to be disposed of by sale are not depreciated while they are classified as held-for-sale. Leases The Company leases certain property and equipment under noncancelable lease agreements. The Company determines if a contract or arrangement contains a lease at inception. All leases are evaluated and classified as either an operating or finance lease. A lease is classified as a finance lease if any of the following criteria are met: (i) ownership of the underlying asset transfers to the Company by the end of the lease term; (ii) the lease contains an option to purchase the underlying asset that the Company is reasonably expected to exercise; (iii) the lease term is for a major part of the remaining economic life of the underlying asset; (iv) the present value of the sum of lease payments and any residual value guaranteed by the Company equals or exceeds substantially all of the fair value of the underlying asset; or (v) the underlying asset is of a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. A lease that does not meet any of the criteria to be classified as a finance lease is classified as an operating lease. Operating leases are included as Right-of-use assets, net, Current portion of operating lease liabilities, and Operating lease liabilities on the Consolidated Balance Sheets. ROU assets and operating lease liabilities are recognized based on the present value of the future lease payments over the lease term at the commencement date. As most of the Company’s leases do not provide an implicit rate for use in determining the present value of future payments, the Company uses an incremental borrowing rate. This incremental borrowing rate reflects the creditworthiness of the Company for a lending period commensurate to the term of the lease and the standard lending practices related to such loans in the respective jurisdiction where the underlying assets are located. ROU assets also include any lease payments made and exclude any lease incentives and initial direct costs incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term, including rent abatement periods and rent holidays. Certain of the Company's leases are subject to annual changes in an index or are subject to adjustments for which the amounts are not readily determinable at lease inception. While lease liabilities are not remeasured as a result of changes to these costs, changes are treated as variable lease payments and recognized in the period in which the obligation for those payments was incurred. Finance leases are included as Property, plant and equipment, net; Current maturities of long-term debt and Long-term debt on the Consolidated Balance Sheets. Finance lease costs are split between depreciation expense related to the asset and interest expense on the lease liability, using the effective rate charged by the lessor. The Company has lease agreements with both lease and non-lease components, which the Company has elected to account for as a single lease component. Additionally, the Company has elected not to record short-term leases, those with expected terms of twelve months or less, on the Consolidated Balance Sheets. Certain lease agreements include fixed escalations, while others include rental payments adjusted periodically for inflation. See Note 8, Debt and Credit Agreements, and Note 9, Leases, for additional information on leases. Business Combinations and Goodwill The Company accounts for business combinations using the acquisition method of accounting, which requires that once control is obtained, all assets acquired and liabilities assumed, including amounts attributable to noncontrolling interests, be recorded at their respective fair values at the date of acquisition. The excess of purchase price over the fair values of identifiable assets and liabilities is recorded as goodwill. The determination of fair value of assets acquired and liabilities assumed requires numerous estimates and assumptions with respect to the timing and amounts of cash flow projections, revenue growth rates, customer attrition rates, discount rates and useful lives. Such estimates are based upon assumptions believed to be reasonable, and, when appropriate, include assistance from independent third-party valuation firms. During the measurement period, which is up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with corresponding offsets to goodwill. In accordance with U.S. GAAP, goodwill is not amortized and is tested for impairment at least annually or more frequently if indicators of impairment exist or if a decision is made to dispose of a business. Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment for which discrete financial information is available. A significant amount of judgment is involved in determining if an indicator of impairment has occurred. Such indicators may include declining cash flows or operating losses at the reporting unit level, a significant adverse change in legal factors or in the business climate, an adverse action or assessment by a regulator, unanticipated competition, a loss of key personnel or a more likely than not expectation that a reporting unit or a significant portion of a reporting unit will be sold or otherwise disposed of, among others. In applying the goodwill impairment test, the Company has the option to perform a qualitative test or a quantitative test . Under the qualitative test, the Company assesses qualitative factors to determine whether it is more likely than not that the fair value of the reporting units is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting unit and other entity and reporting unit specific events. If after assessing these qualitative factors, the Company determines it is “more-likely-than-not” that the fair value of the reporting unit is less than the carrying value, the Company would perform a quantitative test. The quantitative approach of testing for goodwill impairment involves comparing the current fair value of each reporting unit to the carrying value, including goodwill. The Company uses a discounted cash flow model (“DCF model”) to estimate the current fair value of reporting units, as management believes forecasted operating cash flows are the best indicator of current fair value. A number of significant assumptions and estimates are involved in the preparation of DCF models including future revenues and operating margin growth, the weighted-average cost of capital (“WACC”), tax rates, capital spending, pension funding, the impact of business initiatives and working capital projections. These assumptions and estimates may vary significantly among reporting units. DCF models are based on approved long-range plans for the early years and historical relationships and projections for later years. WACC rates are derived from internal and external factors including, but not limited to, the average market price of the Company's stock, shares outstanding, book value of the Company's debt, the long-term risk-free interest rate, and both market and size-specific risk premiums. Due to the many variables noted above and the relative size of the Company's goodwill, differences in assumptions may have a material impact on the results of the Company's annual goodwill impairment testing. If the net book value of a reporting unit were to exceed the Company's determination of the current fair value, then an impairment charge would be recognized as the difference between the fair value and the carrying value. See Note 7, Goodwill and Other Intangible Assets, for additional information. Long-Lived Assets Impairments (Other than Goodwill) Long-lived assets or asset groups are reviewed for impairment when events and circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Long-lived assets or asset groups are reviewed for impairment when events and circumstances indicate the book value of an asset or asset group may be impaired. The Company's policy is to determine if an impairment loss exists when it is determined that the carrying amount of the asset or asset group exceeds the sum of the expected undiscounted future cash flows resulting from use of the asset or asset group and its eventual disposition. Impairment losses are measured as the amount by which the carrying amount of the asset or asset group exceeds its fair value, normally as determined in either open market transactions or through the use of a DCF model. Long-lived assets or asset groups to be disposed of are reported at the lower of the carrying amount or fair value less cost to sell. See Note 18, Other (Income) Expenses, Net for additional information. Deferred Financing Costs The Company has incurred debt issuance costs which are recognized as a reduction of Long-term debt on the Consolidated Balance Sheets. Debt issuance costs are amortized and recognized as interest expense over the contractual term of the related indebtedness or shorter period if appropriate based upon contractual terms. Whenever indebtedness is modified from its original terms, an evaluation is made whether an accounting modification or extinguishment has occurred in order to determine the accounting treatment for debt issuance costs related to the debt modification. 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 Segment. Product revenues include portions of the Harsco Environmental Segment. Harsco Environmental - This Segment provides on-site services, under long-term contracts, for material logistics; product quality improvement and resource recovery from iron, steel and metals manufacturing; manufactures and sells industrial abrasives and roofing granule products; and manufactures aluminum dross and scrap processing systems. • Service revenues are recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an output method based on work performed (liquid steel tons processed, weight of material handled, etc.) to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms, which may include both fixed and variable portions. The fixed portion is recognized as earned (normally monthly) over the contractual period. The variable portion is recognized as services are performed and differs based on the volume of services performed. Given the long-term nature of these arrangements, most contracts permit periodic adjustment of either the variable or both the fixed and variable portions based on the changes in macroeconomic indicators, including changes in commodity prices. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis as services are performed. • Product revenues are recognized at the point when control transfers to the customer. Control generally transfers at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. Transaction prices are based on contractual terms, which are generally fixed and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. Amounts are billed and payable upon completion of each transaction. • Product revenues in the aluminum dross and scrap process systems business are generally recognized over time as control is transferred to the customer. Control transfers over time because aluminum dross and scrap systems are customized, have no alternate use and the Company has an enforceable right to payment. The Company utilizes an input method based on costs incurred ("cost-to-cost method") to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. The Company may receive periodic payments associated with key milestones with any remaining consideration billed and payable upon completion of the transaction. Harsco Clean Earth - This Segment provides specialty waste processing and beneficial reuse solutions for hazardous wastes, and soil and dredged materials. • Revenues are recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an output method based on the amount of materials received for processing to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms which are principally variable based on volume and recognized as services are performed. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis. Harsco Rail - This business sells railway track maintenance equipment, after-market parts, Protran/safety equipment and provides railway track maintenance services. • For standard railway track maintenance equipment sales, revenue is recognized at the point when control transfers to the customer. Control generally transfers at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. In certain railway track maintenance equipment sales, revenue is recognized over time because such equipment is highly customized, has no alternate use and the Company has an enforceable right to payment. The former Harsco Rail Segment uses the cost-to-cost method to measure progress because it is the measure that best depicts the transfer of control to the customer, which occurs as the former Harsco Rail Segment incurs costs under the contracts. Under the cost-to-cost method, the extent of progress towards completion is based on the ratio of costs incurred to total estimated costs at completion which includes both actual costs already incurred and the estimated costs to complete. Accounting for contracts with customers using the cost-to-cost method requires significant judgment relative to assessing risks, estimating contract revenues (including estimates of variable consideration, if applicable, as well as estimating any liquidating damages or penalties related to performance), estimating contract costs (including estimating engineering costs to design the machine and the material, labor and overhead manufacturing costs to build the machine); making assumptions for schedule and technical items; properly executing the engineering and design phases consistent with customer expectations; the availability and costs of labor and material resources; productivity; and evaluating whether a significant financing component is present. Due to the number of years it may take to complete certain contracts and the scope and nature of the work required to be performed on those contracts, estimating total revenues and costs at completion is inherently complicated and subject to many variables. Transaction prices are based on contracted terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing either the adjusted market assessment or expected cost plus a margin approach. For certain transactions, the Company receives periodic payments associated with key milestones. In limited instances, those payments are intended to provide financing with such transactions being treated as including a significant financing component. Any remaining consideration is billed and payable upon completion of the transaction. Railway track maintenance equipment revenue of approximately $102 million was recognized using the cost-to-cost method in 2021, the net profit or loss of which is included in Income (loss) from discontinued businesses in the Consolidated Statements of Operations. • For after-market parts sales and Protran/safety equipment, revenue is recognized at the point when control transfers to the customer. Control generally transfers to the customer at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. Transaction prices are based on contracted terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. Amounts are billed and payable upon completion of each contract. • For railway track maintenance services, revenue is recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an appropriate output method based on work performed (feet, miles, shifts worked, etc.) to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contracted terms, which are generally variable. The variable portion is recognized as services are performed and differs based on the value of services. Given the long-term nature of these arrangements, most contracts permit periodic adjustment based on the changes in macroeconomic indicators. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis as services are performed. The Company has elected to utilize the following practical expedients on an ongoing basis: • The Company has not adjusted the promised amount of consideration for the effects of a significant financing component if the Company expects, at contract inception, that the period between when the Company transfers the promised good or services to the customer and when the customer pays for that good or service would be one year or less; and • The Company has elected to exclude disclosures related to unsatisfied performance obligations where the related contract has a duration of one year or less; or where the consideration is entirely variable. Accordingly, the Company's disclosure related to unsatisfied performance obligations is limited to the fixed portion of fees related to metals services in the Harsco Environmental Segment. Taxes assessed by governmental authorities that are both imposed on and concurrent with a specific revenue-producing transaction, that are collected by the Company from a customer, are excluded from revenue. Additionally, in certain contracts, the Company facilitates shipping and handling activities after control has transferred to the customer. The Company has elected to record all shipping and handling activities as costs to fulfill a contract. In situations where the shipping and handling costs have not been incurred at the time revenue is recognized, the respective shipping and handling costs are accrued. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of the events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the consolidated financial statements and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company records deferred tax assets to the extent that the Company believes that these assets will more likely than not be realized. In making such determinations, the Company considers all available positive and negative evidence, including future reversals of existing deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial results. If the Company determines that it will not be able to realize deferred income tax assets in the future, a valuation allowance is recorded. If sufficient positive evidence arises in the future indicating that all or a portion of the deferred tax assets meet the more likely than not standard for realization, the valuation allowance would be reduced accordingly in the period that such a conclusion is reached. The Company prepares and files tax returns based on interpretation of tax laws and regulations and records its provision for income taxes based on these interpretations. Uncertainties may exist in estimating the Company's tax provisions and in filing tax returns in the many jurisdictions in which the Company operates, and as a result these interpretations may give rise to an uncertain tax position. The tax benefit from an uncertain tax position is recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on its technical merits. Each subsequent period the Company determines if existing or new uncertain tax positions meet a more likely than not recognition threshold and adjusts accordingly. The Company recognizes interest and penalties related to unrecognized tax benefits within Income tax expense in the accompanying Consolidated Statements of Operations. Liabilities for uncertain tax positions are included in Other liabilities on the Consolidated Balance Sheets. The significant assumptions and estimates described in the preceding paragraphs are important contributors to the effective tax rate each year. See Note 11, Income Taxes, for additional information. Accrued Insurance and Loss Reserves The Company retains a significant portion of the risk for certain U.S. workers' compensation, U.K. employers' liability, automobile, general and product liability losses. During 2021, 2020 and 2019, the Company recorded insurance expense from continuing operations related to these lines of coverage of $25.6 million, $21.1 million and $12.5 million, respectively. Reserves have been recorded that reflect the undiscounted estimated liabilities including claims incurred but not reported. When a recognized liability is covered by third-party insurance, the Company records an insurance claim receivable to reflect the covered liability. Changes in the estimates of the reserves are included in net income(loss) in the period determined. During 2021, 2020 and 2019, the Company recorded insurance reserve adjustments that decreased pre-tax insurance expense from continuing operations for self-insured programs by $0.2 million, $1.3 million and $0.8 million, respectively. At December 31, 2021 and 2020, the Company has recorded liabilities of $28.3 million and $27.3 million, respectively, related to both asserted as well as unasserted insurance claims. Included in the balances at December 31, 2021 and 2020 were $4.1 million and $5.2 million, respectively, of recognized liabilities covered by insurance carriers. Amounts estimated to be paid within one year have been included in Other current liabilities, with the remainder included in Other liabilities, on the Consolidated Balance Sheets. Foreign Currency Translation The financial statements of the Company's subsidiaries outside the U.S., except for those subsidiaries located in highly inflationary economies and those entities for which the U.S. dollar is the currency of the primary economic environment in which the entity operates, are measured using the local currency as the functional currency. Assets and liabilities of these subsidiaries are translated at the exchange rates at the balance sheet date. Resulting translation adjustments are recorded in the cumulative translation adjustment account, a separate component of AOCI on the Consolidated Balance Sheets. Income and expense items are translated at average monthly exchange rates. Gains and losses from foreign currency transactions are included in Operating income from continuing operations. For subsidiaries operating in highly inflationary economies, and those entities for which the U.S. dollar is the currency of the primary economic environment in which the entity operates, gains and losses on foreign currency transactions and balance sheet translation adjustments are included in Operating income from continuing operations. Financial Instruments and Hedging The Company has operations throughout the world that are exposed to fluctuations in related foreign currencies in the normal course of business. The Company seeks to reduce exposure to foreign currency fluctuations through the use of forward exchange contracts. The Company does not hold or issue financial instruments for trading purposes and it is the Company's policy to prohibit the use of derivatives for speculative purposes. The Company has a Foreign Currency Risk Management Committee that meets periodically to monitor foreign currency risks. The Company executes foreign currency exchange forward contracts to hedge transactions for firm purchase commitments, to hedge variable cash flows of forecasted transactions and for export sales denominated in foreign currencies. These contracts are generally for 90 days or less; however, where appropriate, longer-term contracts may be utilized. For those contracts that are designated as qualified cash flow hedges, gains or losses are recorded in AOCI on the Consolidated Balance Sheets. The Company uses interest rate swaps in conjunction with certain debt issuances in order to secure a fixed interest rate. The interest rate swaps are recorded on the Consolidated Balance Sheets at fair value, with changes in value attributed to the effect of the swaps’ interest spread and changes in the credit worthiness of the counter-parties recorded in AOCI. Amounts recorded in AOCI on the Consolidated Balance Sheets are reclassified into income in the same period or periods during which the hedged forecasted transaction affects income. The cash flows from these contracts are classified consistent with the cash flows from the transaction being hedged (e.g., the cash flows related to contracts to hedge the purchase of fixed assets are included in cash flows from investing activities, etc.). The Company also enters into certain forward exchange contracts that are not designated as hedges. Gains and losses on these contracts are recognized in operations based on changes in fair market value. For fair value hedges of a firm commitment, the gain or loss on the derivative and the offsetting gain or loss on the hedged firm commitment are recognized currently in operations. See Note 15, Financial Instruments, for additional information. Earnings Per Share Basic earnings per share are calculated using the weighted-average shares of common stock outstanding, while diluted earnings per share reflect the dilutive effects of stock-based compensation. Dilutive securities are not included in the computation of loss per share when the Company reports a net loss from continuing operations as the impact would be anti-dilutive. All share and per share amounts are restated for any stock splits and stock dividends that occur prior to the issuance of the financial statements. See Note 13, Capital Stock, for additional information. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses. Actual results could differ from those estimates. Impact of COVID-19 Beginning in early 2020, overall global economic conditions were significantly impacted by COVID-19. The Company operated, since the onset of the pandemic, as a provider of certain essential services in the U.S. and other countries and overall business conditions have strengthened since the second quarter of 2020. 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 d

Recently Adopted and Recently I

Recently Adopted and Recently Issued Accounting Standards	12 Months Ended
	Dec. 31, 2021
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 2021: On January 1, 2021 the Company adopted changes issued by the FASB 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. These changes did not have a material impact on the Company's consolidated financial statements. The following accounting standards have been issued and become effective for the Company at a future date: 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. In January 2021, the FASB issued additional clarification changes. 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 the Company's 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. The changes become effective January 1, 2022. Management has concluded that this standard will not have an impact on the Company's consolidated financial statements. In November 2021, the FASB issued changes that improve the transparency of government assistance received by entities. The changes require disclosure of the nature of transactions, including significant terms and conditions, accounting policies used, and financial statement line items affected by the transactions. The changes become effective January 1, 2022. Other than required expanded disclosures, the adoption of these changes will not have a material impact on the Company's consolidated financial statements.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Harsco Rail Segment In November 2021, the Company announced its intention to sell the Rail business. The former Harsco Rail Segment has historically been a separate reportable segment with primary operations in the United States, Europe and Asia Pacific. The former Harsco Rail Segment's balance sheet positions as of December 31, 2021 and 2020 are presented as Assets held-for-sale and Liabilities of assets held-for-sale in the Consolidated Balance Sheets and are summarized as follows: (in thousands) December 31 December 31 Trade accounts receivable, net $ 33,689 $ 52,077 Other receivables 4,740 3,045 Inventories 103,560 112,013 Current portion of contract assets 94,597 52,240 Other current assets 25,442 27,703 Property, plant and equipment, net 39,524 37,855 Right-of-use assets, net 3,108 4,354 Goodwill 13,026 13,026 Intangible assets, net 3,081 3,449 Deferred income tax assets 6,064 4,906 Other assets 6,432 6,316 Total Rail assets included in Assets held-for-sale $ 333,263 $ 316,984 Accounts payable $ 46,076 $ 53,937 Accrued compensation 2,171 1,503 Current portion of operating lease liabilities 1,619 1,745 Current portion of advances on contracts 62,401 37,462 Other current liabilities 49,732 33,280 Advances on contracts — 44,731 Operating lease liabilities 1,775 2,734 Deferred tax liabilities 5,736 4,461 Other liabilities 982 925 Total Rail liabilities included in Liabilities of assets held-for-sale $ 170,492 $ 180,778 The results of the former Harsco Rail Segment are presented as discontinued operations and, as such, have been excluded from both continuing operations and segment results for the years ended December 31, 2021, 2020, and 2019. Certain key selected financial information included in Income (loss) from discontinued operations, net of tax for the former Harsco Rail Segment is as follows: Years ended December 31 (In thousands) 2021 2020 2019 Amounts directly attributable to the former Harsco Rail Segment: Service revenues $ 32,425 $ 31,642 $ 30,254 Product revenues 266,221 298,189 269,119 Cost of services sold 17,272 23,480 21,883 Cost of products sold 251,897 235,040 192,310 Income (loss) from discontinued businesses (19,967) 23,096 25,406 Additional amounts allocated to the former Harsco Rail Segment: Selling, general and administrative expenses (a) $ 178 $ — $ — (a) The Company has allocated directly attributable transaction costs to discontinued operations. The Company has retained corporate overhead expenses previously allocated to the former Harsco Rail Segment of $4.2 million for each of the years ended December 31, 2021, 2020, and 2019 as part of Selling, general and administrative expenses on the Consolidated Statements of Operations. The Company's former Harsco Rail segment is currently manufacturing highly-engineered equipment under large long-term fixed-price contracts with the SBB, the infrastructure manager for most of the railway in the U.K. ("Network Rail"), and the national railway company in Germany ("Deutsche Bahn"). Post-engineering, the Company has made significant progress in the development of the prototype/initial units for certain portions of these contracts during the fourth quarter of 2021, which has provided clarity in terms of material requirements and associated cost impacts. As a result, in the fourth quarter of 2021, the Company recognized estimated forward loss provisions related to these contracts of $33.4 million. The principal driver of the provisions was recent expected cost inflation for all contracts, including for vendors in Europe who perform the manufacturing and assembly of certain equipment under these contracts. In addition, the estimate for liquidated damages for delivery delays for the Network Rail contract was increased based on the current status of negotiations with the customer during the quarter, as well as delayed prototype build and the resulting delayed delivery schedule. 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 first contract with SBB is complete, and the second contract is 78% complete as of December 31, 2021. The contracts with Network Rail and Deutsche Bahn are 42% and 18% complete, respectively, as of December 31, 2021. The following is selected financial information included on the Consolidated Statements of Cash Flows attributable to the former Harsco Rail Segment: Years Ended December 31 (In thousands) 2021 2020 2019 Non-cash operating items Depreciation and amortization $ 4,329 $ 5,450 $ 4,876 Cash flows from investing activities Purchases of property, plant and equipment 1,406 7,962 15,274 ESOL On April 6, 2020 the Company completed the 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 cash, 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 fair value recorded for the assets acquired and liabilities assumed for ESOL is as follows: (In millions) April 6 Measurement Period Adjustments Final Valuation Cash and cash equivalents $ 0.4 $ — $ 0.4 Trade accounts receivable 124.1 (1.5) 122.6 Inventory 5.0 — 5.0 Other current assets 0.7 (0.7) — Property, plant and equipment 105.3 (3.9) 101.4 Right-of-use assets, net 56.0 — 56.0 Goodwill 152.0 1.3 153.3 Intangible assets 161.0 — 161.0 Other assets 0.2 — 0.2 Accounts payable (48.6) (1.5) (50.1) Accrued expenses (17.5) (1.8) (19.3) Current portion of operating lease liabilities (16.6) — (16.6) Other current liabilities (6.4) (0.2) (6.6) Environmental liabilities (24.4) — (24.4) Deferred income taxes (15.5) (1.5) (17.0) 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 valuation of identifiable intangible assets and amortization periods for ESOL and the non-compete agreement: (Dollars in millions) Weighted-Average Amortization Period April 6 Measurement Period Adjustments Final Valuation 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 years ended December 31, 2020 and 2019 included ESOL direct acquisition and integration costs of $49.0 million and $7.3 million, respectively, which are included in Selling, general and administrative expenses, within the Corporate function, in the Consolidated Statements of Operations. In addition to the acquisition and integration costs reflected in the Consolidated Statements of Operations, 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 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 wastes, soil and dredged materials, 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. At December 31, 2021 and 2020, the present value of the expected reimbursement is approximately $8 million and $11 million, respectively. See Footnote 18, Other (Income) Expenses, Net, for additional details. The fair value recorded for the assets acquired and liabilities assumed for Clean Earth is as follows: (In millions) June 28 Measurement Period Adjustments Final Valuation Cash and cash equivalents $ 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, net 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 (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 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: (Dollars in millions) Weighted-Average Amortization Period June 28 Measurement Period Adjustments Final Valuation Permits 18 years $ 176.1 $ (6.0) $ 170.1 Customer relationships and backlog 8 years 33.4 (12.9) 20.5 Air rights Usage based (b) 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 (b) 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 year ended December 31, 2019 included Clean Earth direct acquisition costs of $15.2 million, which are included in Selling, general and administrative expenses, within the Corporate function, in the Consolidated Statements of Operations. In addition to the acquisition costs reflected in the Consolidated Statements of Operations, 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 Consolidated Balance Sheets. Harsco Industrial Segment In May 2019, the Company announced its intent to divest the businesses that comprised the Harsco Industrial Segment; AXC, IKG and PK. These disposals represented a strategic shift and accelerated the transformation of the Company's portfolio of businesses into a leading provider of environmental solutions and services. In July 2019, the Company sold AXC for $600 million in cash and recognized a gain on sale of $527.9 million pre-tax (or approximately $421 million after-tax). In November 2019, the Company sold PK for approximately $60 million in cash and recognized a gain on sale of $41.2 million pre-tax (or approximately $33 million after-tax). In January 2020, the Company sold IKG for $85.0 million, including a note receivable with a face value of $40.0 million and recognized an $18.4 million pre-tax gain on sale (or approximately $9 million after-tax). In 2019 the gains on the sales of AXC and PK and in 2020 the gain on the sale of IKG have been recorded in the Consolidated Statements of Operations as discontinued operations. The Harsco Industrial Segment was historically 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 years ended December 31, 2021, 2020, and 2019. Certain key selected financial information included in net income from discontinued operations for the former Harsco Industrial Segment is as follows: Years ended December 31 (In thousands) 2021 2020 2019 Amounts directly attributable to the former Harsco Industrial Segment: Total revenues $ — $ 10,203 $ 306,972 Cost of products sold — 8,082 224,811 Gain on sale from discontinued businesses — 18,281 569,135 Income (loss) from discontinued businesses (3,510) (1,578) 27,823 Additional amounts allocated to the former Harsco Industrial Segment: Selling, general and administrative expenses (c) $ 3,510 $ 2,695 $ 8,429 Interest expense (d) — — 11,237 Loss on early extinguishment of debt (e) — — 5,314 (c) The Company allocated directly attributable transaction costs to discontinued operations. In addition, this caption includes costs directly attributable to retained contingent liabilities of the former Harsco Industrial Segment. (d) The Company allocated interest expense, including a portion of the amount reclassified into income for the Company's interest rate swaps, amortization of deferred financing costs, and $2.7 million related to interest rate swap terminations which were directly attributed with the mandatory repayment of certain debt resulting from the AXC disposal. (e) The Company allocated the $5.3 million write-off of deferred financing costs to discontinued operations as it directly attributed to the mandatory repayment of certain debt resulting from the AXC disposal. The Company retained corporate overhead expenses previously allocated to the former Harsco Industrial Segment of $4.0 million in 2019 as part of Selling, general and administrative expenses on the Consolidated Statements of Operations.

Accounts Receivable and Note Re

Accounts Receivable and Note Receivable (Notes)	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Accounts Receivable and Note Receivable	Accounts Receivable and Note Receivable Accounts receivable consist of the following: (In thousands) December 31 December 31 Trade accounts receivable $ 385,143 $ 362,801 Less: Allowance for expected credit losses (7,262) (7,488) Trade accounts receivable, net $ 377,881 $ 355,313 Other receivables (a) $ 33,059 $ 31,208 (a) Other receivables include employee receivables, insurance receivable, tax claims and refunds and other miscellaneous receivables not included in Trade accounts receivable, net. The provision for doubtful accounts related to trade accounts receivable was as follows: Years Ended December 31 (In thousands) 2021 2020 2019 Provision for expected credit losses and doubtful accounts related to trade accounts receivable $ 589 $ 1,961 $ 7,123 The provision for doubtful accounts in 2019 primarily included a provision in the Harsco Environmental Segment related to a customer in the U.K entering administration which was subsequently written off in 2020. At December 31, 2021 $8.0 million of the Company's trade accounts receivable were past due by twelve months or more, with $5.4 million of this amount reserved. 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 and is included in the caption Other assets on the Consolidated Balance Sheets. 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. During the twelve months ended December 31, 2021, the Company received a payment of $6.4 million related to excess cash flow. At December 31, 2021 the amortized cost of the note receivable was $31.0 million, compared with a fair value of $32.3 million. (In thousands) December 31 December 31 Note receivable $ 31,025 $ 35,806

Inventories

Inventories	12 Months Ended
	Dec. 31, 2021
Accounts Receivable and Inventories [Abstract]
Inventories	Inventories Inventories consist of the following: (In thousands) December 31 December 31 Finished goods $ 8,323 $ 7,749 Work-in-process 5,393 2,795 Raw materials and purchased parts 21,188 20,259 Stores and supplies 35,589 30,198 Total inventories $ 70,493 $ 61,001 Valued at lower of cost or market: LIFO basis $ 14,133 $ 14,690 FIFO basis 7,567 5,485 Average cost basis 48,793 40,826 Total inventories $ 70,493 $ 61,001

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment consist of the following: (In thousands) Estimated December 31 December 31 Land — $ 73,067 $ 73,237 Land improvements 5-20 years 16,970 17,500 Buildings and improvements (a) 5-30 years 221,236 224,909 Machinery and equipment (b) 3-20 years 1,507,214 1,512,966 Uncompleted construction — 63,816 39,587 Gross property, plant and equipment 1,882,303 1,868,199 Less: Accumulated depreciation (1,228,390) (1,237,845) Property, plant and equipment, net $ 653,913 $ 630,354 (a) Buildings and improvements include leasehold improvements that are amortized over the shorter of their useful lives or the initial term of the lease. (b) Includes information technology hardware and software.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill by Segment The following table reflects the changes in carrying amounts of goodwill by segment for the years ended December 31, 2021 and 2020: (In thousands) Harsco Environmental Harsco Consolidated Balance at December 31, 2019 $ 395,113 $ 330,230 $ 725,343 Changes to goodwill (a) 1,480 152,417 153,897 Foreign currency translation 9,808 — 9,808 Balance at December 31, 2020 406,401 482,647 889,048 Changes to goodwill — 1,232 1,232 Foreign currency translation (7,171) — (7,171) Balance at December 31, 2021 $ 399,230 $ 483,879 $ 883,109 (a) The changes to goodwill related to the acquisition of ESOL, and immaterial acquisitions in the Harsco Environmental segment. See Note 3, Acquisitions and Dispositions. The Company's methodology for determining reporting unit fair value is described in Note 1, Summary of Significant Accounting Policies. Performance of the Company's 2021 annual impairment test did not result in impairment of any of the Company's reporting units. Intangible Assets Net intangible assets totaled $402.8 million at December 31, 2021 and $435.1 million at December 31, 2020. The following table reflects these intangible assets by major category: December 31, 2021 December 31, 2020 (In thousands) Gross Carrying Accumulated Gross Carrying Accumulated Customer related $ 104,322 $ 54,057 $ 105,222 $ 46,267 Permits 309,069 34,822 308,705 18,955 Technology related 39,886 13,415 40,274 9,654 Trade names 30,738 6,842 30,779 4,272 Air rights 26,139 1,675 26,139 1,044 Patents 179 138 192 139 Non-compete agreement 2,500 1,094 2,500 469 Other 3,407 1,396 3,335 1,230 Total $ 516,240 $ 113,439 $ 517,146 $ 82,030 Amortization expense for intangible assets was $32.2 million, $30.6 million and $15.2 million for 2021, 2020 and 2019, respectively. The following table shows the estimated amortization expense for the next five fiscal years based on current intangible assets. (In thousands) 2022 2023 2024 2025 2026 Estimated amortization expense (b) $ 31,600 $ 31,600 $ 31,100 $ 30,900 $ 28,900 (b) These estimated amortization expense amounts do not reflect the potential effect of future foreign currency exchange rate fluctuations.

Debt and Credit Agreements

Debt and Credit Agreements	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt and Credit Agreements	Debt and Credit Agreements The Company's long-term debt consists of the following: (In thousands) December 31 December 31 Senior Secured Credit Facilities (a) : New Term Loan with an interest rate of 2.75% at December 31, 2021 $ 497,500 $ — Term Loan A with an interest rate of 3.50% at December 31, 2020 — 280,000 Term Loan B with an interest rate of 3.25% at December 31, 2020 — 218,188 Revolving Credit Facility with an average interest rate of 2.5% and 2.8% at December 31, 2021 and 2020, respectively 362,000 281,000 5.75% Senior Notes due July 31, 2027 500,000 500,000 Other financing payable (including capital leases) in varying amounts due principally through 2026 with a weighted-average interest rate of 4.7% and 5.0% at December 31, 2021 and 2020, respectively 28,389 21,344 Total debt obligations 1,387,889 1,300,532 Less: deferred financing costs (18,217) (15,767) Total debt obligations, net of deferred financing costs 1,369,672 1,284,765 Less: current maturities of long-term debt (10,226) (13,576) Long-term debt $ 1,359,446 $ 1,271,189 (a) The current portion of long-term debt related to the Senior Secured Credit Facilities was $5.0 million and $10.5 million with the remainder reflected as Long-term debt at December 31, 2021 and 2020, respectively. The maturities of long-term debt for the four years following December 31, 2022 are as follows: (In thousands) 2023 $ 17,331 2024 9,351 2025 7,560 2026 368,558 Cash payments for interest on debt were $60.9 million, $59.5 million and $27.6 million in 2021, 2020 and 2019, respectively. Senior Secured Credit Facilities March 2021 Amendment In March 2021, the Company amended its Senior Secured Credit Facilities to, among other things, extend the maturity date of the Revolving Credit Facility to March 10, 2026, and to modify aspects of its total net leverage ratio covenant. As a result of this amendment, the net debt to consolidated adjusted EBITDA ratio covenant was increased to 5.75 through December 2021 and then decreases quarterly until reaching 4.50 in December 2022 and 4.00 in March 2023. In addition the Company issued the New Term Loan, as an additional tranche, under the Senior Secured Credit Facilities, in an aggregate principal amount of $500 million. The New Term Loan bears interest at a rate per annum of 1.25% over base rate, subject to a zero floor, or 2.25% over LIBOR, subject to a 0.50% floor. The New Term Loan is subject to quarterly amortization of principal of 0.25%, beginning September 30, 2021. The proceeds of the New Term Loan were used to repay in full the outstanding Term Loan A and Term Loan B under the Senior Secured Credit Facilities, which were due on June 28, 2024 and December 8, 2024, respectively. The New Term Loan matures on March 10, 2028, or earlier, on the date that is 91 days prior to the maturity date of the Company’s 5.75% Senior Notes, due 2027, if such Senior Notes are outstanding or have not been refinanced at such time. In October 2021, the Company amended its Senior Secured Credit Facilities to, among other things, to make certain amendments in connection with the discontinuation of LIBOR. At December 31, 2021, the Company was in compliance with all covenants for the Senior Secured Credit Facilities. During the twelve months ended December 31, 2021, 2020 and 2019, the Company recognized $5.5 million, $1.9 million and $1.0 million, respectively, of fees and expenses related to amendments to the Senior Secured Credit Facilities in the caption Unused debt commitment, amendment fees and loss on the extinguishment of debt on the Consolidated Statements of Operations. The amount for 2021 includes a write-off of $2.7 million of previously recorded deferred financing costs. The Company capitalized fees of $7.8 million related to the March 2021 Amendment. In addition, on February 22, 2022, the Company amended its Senior Credit Facilities (“Amendment No. 9 to the Third Amended and Restated Credit Agreement”) to reset the levels of the net debt to consolidated adjusted EBITDA ratio covenant. As a result of this amendment, the net debt to consolidated adjusted EBITDA ratio covenant was set at 5.75 for the quarter ending March 31, 2022, and then decreases quarterly by 0.25 until reaching 4.00 for the quarter ending December 31, 2023 and thereafter. In addition, upon closing on the divestiture of the former Harsco Rail Segment, the net debt to consolidated adjusted EBITDA ratio covenant will decrease by an additional 0.25, provided, however, it will not go below 4.00. See Note 20 Subsequent Events and Item 9B Other Information for discussion of the Amendment No. 9 to the Third Amended and Restated Credit Agreement. The Credit Agreement imposes certain restrictions including, but not limited to, restrictions as to types and amounts of debt of liens that may be incurred by the Company; limitations on increases in dividend payments; limitations on repurchases of the Company's stock and limitations on certain acquisitions by the Company. With respect to the Senior Secured Credit Facilities, the obligations of the Company are guaranteed by substantially all of the Company’s current and future wholly-owned domestic subsidiaries (“Guarantors”). All obligations under the Senior Credit Facility, and the guarantees of those obligations, are secured, subject to certain exceptions, by substantially all of the Company’s assets and the assets of the Guarantors. The Credit Agreement requires certain mandatory prepayments of the New Term Loan, subject to certain exceptions, based on net cash proceeds of certain sales or distributions of assets, as well as certain casualty and condemnation events, in some cases subject to reinvestment rights and certain other exceptions; net cash proceeds of any issuance of debt, excluded permitted debt issuances; and a percentage of excess cash flow, as defined by the Credit Agreement, during a fiscal year. Revolving Credit Facility Borrowings under the Revolving Credit Facility, a U.S.-based program, bear interest at a rate per annum ranging from 50 to 150 basis points over base rate or 150 to 250 basis points over adjusted LIBOR, subject to a 0% floor. Any principal amount outstanding under the Revolving Credit Facility is due and payable on its maturity on March 10, 2026. The following table shows the amount outstanding under the Revolving Credit Facility and available credit at December 31, 2021. December 31, 2021 (In thousands) Facility Outstanding Outstanding Letters of Credit Available Revolving Credit Facility $ 700,000 $ 362,000 $ 29,824 $ 308,176 Other In 2019, the Company recognized $6.7 million of expenses in the caption Unused commitment fees, amendment fees and loss on extinguishment of debt on the Consolidated Statements of Operations, for fees and other costs related to bridge financing commitments that the Company arranged in the event that the Senior Notes were not issued prior to the acquisition of Clean Earth. The Senior Notes were issued prior to completion of the Clean Earth acquisition thus the bridge financing commitments were not utilized.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Leases The components of lease expense were as follows: (In thousands) 2021 2020 2019 Finance leases: Amortization expense $ 2,510 $ 1,523 $ 1,234 Interest on lease liabilities 495 184 50 Operating leases 32,544 28,537 13,754 Variable and short-term leases 47,780 40,953 22,201 Sublease income (53) (202) (198) Total lease expense from continuing operations $ 83,276 $ 70,995 $ 37,041 Supplemental cash flow information related to leases was as follows: (In thousands) 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows used by operating activities - Operating leases (a) $ 33,645 $ 28,057 $ 15,143 Cash flows used by financing activities - Finance leases 2,847 1,367 1,317 ROU assets obtained in exchange for lease obligations: Operating leases (b) $ 42,442 $ 69,044 $ 65,525 Finance leases 11,495 6,220 2,658 (a) Cash flows include cash paid for operating leases of discontinued operations. (b) Cash flows include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL in 2020. See Note 3, Acquisitions and Dispositions, for additional information. Supplemental balance sheet information related to leases was as follows: (In thousands) 2021 2020 Operating Leases (c): Operating lease ROU assets $ 101,576 $ 92,495 Current portion of operating lease liabilities 25,590 23,117 Operating lease liabilities 74,571 67,126 Finance Leases: Property, plant and equipment, net $ 17,185 $ 8,434 Current maturities of long-term debt 3,756 1,683 Long-term debt 13,736 6,867 (c) The 2021 operating lease ROU assets and operating lease liabilities include a $15 million adjustment to record certain leases for ESOL. These leases have been incorrectly treated as short term leases versus operating leases since ESOL's acquisition on April 6, 2020. Supplemental additional information related to leases was as follows: 2021 2020 Other information: Weighted average remaining lease term - Operating leases (in years) 7.14 8.22 Weighted average remaining lease term - Finance leases (in years) 5.88 8.20 Weighted average discount rate - Operating leases 5.9 % 6.1 % Weighted average discount rate - Finance leases 4.6 % 5.1 % Maturities of lease liabilities were as follows: (In thousands) Operating Leases Finance Year Ending December 31: 2022 $ 30,347 $ 4,483 2023 24,959 4,311 2024 18,612 3,901 2025 12,923 2,834 2026 8,641 1,733 After 2026 31,890 3,078 Total lease payments 127,372 20,340 Less: Imputed interest (27,211) (2,848) Total lease liabilities $ 100,161 $ 17,492 The Company's leases, excluding short-term leases, have remaining terms of less than one year to 29 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 December 31, 2021, the Company has additional operating leases for property and equipment that have not yet commenced, with estimated ROU assets and lease liabilities of approximately $17 million to be recognized upon anticipated lease commencements in the first and second quarters of 2022. There are no material residual value guarantees or material restrictive covenants in any of the Company's leases.
Leases	Leases The components of lease expense were as follows: (In thousands) 2021 2020 2019 Finance leases: Amortization expense $ 2,510 $ 1,523 $ 1,234 Interest on lease liabilities 495 184 50 Operating leases 32,544 28,537 13,754 Variable and short-term leases 47,780 40,953 22,201 Sublease income (53) (202) (198) Total lease expense from continuing operations $ 83,276 $ 70,995 $ 37,041 Supplemental cash flow information related to leases was as follows: (In thousands) 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows used by operating activities - Operating leases (a) $ 33,645 $ 28,057 $ 15,143 Cash flows used by financing activities - Finance leases 2,847 1,367 1,317 ROU assets obtained in exchange for lease obligations: Operating leases (b) $ 42,442 $ 69,044 $ 65,525 Finance leases 11,495 6,220 2,658 (a) Cash flows include cash paid for operating leases of discontinued operations. (b) Cash flows include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL in 2020. See Note 3, Acquisitions and Dispositions, for additional information. Supplemental balance sheet information related to leases was as follows: (In thousands) 2021 2020 Operating Leases (c): Operating lease ROU assets $ 101,576 $ 92,495 Current portion of operating lease liabilities 25,590 23,117 Operating lease liabilities 74,571 67,126 Finance Leases: Property, plant and equipment, net $ 17,185 $ 8,434 Current maturities of long-term debt 3,756 1,683 Long-term debt 13,736 6,867 (c) The 2021 operating lease ROU assets and operating lease liabilities include a $15 million adjustment to record certain leases for ESOL. These leases have been incorrectly treated as short term leases versus operating leases since ESOL's acquisition on April 6, 2020. Supplemental additional information related to leases was as follows: 2021 2020 Other information: Weighted average remaining lease term - Operating leases (in years) 7.14 8.22 Weighted average remaining lease term - Finance leases (in years) 5.88 8.20 Weighted average discount rate - Operating leases 5.9 % 6.1 % Weighted average discount rate - Finance leases 4.6 % 5.1 % Maturities of lease liabilities were as follows: (In thousands) Operating Leases Finance Year Ending December 31: 2022 $ 30,347 $ 4,483 2023 24,959 4,311 2024 18,612 3,901 2025 12,923 2,834 2026 8,641 1,733 After 2026 31,890 3,078 Total lease payments 127,372 20,340 Less: Imputed interest (27,211) (2,848) Total lease liabilities $ 100,161 $ 17,492 The Company's leases, excluding short-term leases, have remaining terms of less than one year to 29 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 December 31, 2021, the Company has additional operating leases for property and equipment that have not yet commenced, with estimated ROU assets and lease liabilities of approximately $17 million to be recognized upon anticipated lease commencements in the first and second quarters of 2022. There are no material residual value guarantees or material restrictive covenants in any of the Company's leases.
Leases	Leases The components of lease expense were as follows: (In thousands) 2021 2020 2019 Finance leases: Amortization expense $ 2,510 $ 1,523 $ 1,234 Interest on lease liabilities 495 184 50 Operating leases 32,544 28,537 13,754 Variable and short-term leases 47,780 40,953 22,201 Sublease income (53) (202) (198) Total lease expense from continuing operations $ 83,276 $ 70,995 $ 37,041 Supplemental cash flow information related to leases was as follows: (In thousands) 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows used by operating activities - Operating leases (a) $ 33,645 $ 28,057 $ 15,143 Cash flows used by financing activities - Finance leases 2,847 1,367 1,317 ROU assets obtained in exchange for lease obligations: Operating leases (b) $ 42,442 $ 69,044 $ 65,525 Finance leases 11,495 6,220 2,658 (a) Cash flows include cash paid for operating leases of discontinued operations. (b) Cash flows include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL in 2020. See Note 3, Acquisitions and Dispositions, for additional information. Supplemental balance sheet information related to leases was as follows: (In thousands) 2021 2020 Operating Leases (c): Operating lease ROU assets $ 101,576 $ 92,495 Current portion of operating lease liabilities 25,590 23,117 Operating lease liabilities 74,571 67,126 Finance Leases: Property, plant and equipment, net $ 17,185 $ 8,434 Current maturities of long-term debt 3,756 1,683 Long-term debt 13,736 6,867 (c) The 2021 operating lease ROU assets and operating lease liabilities include a $15 million adjustment to record certain leases for ESOL. These leases have been incorrectly treated as short term leases versus operating leases since ESOL's acquisition on April 6, 2020. Supplemental additional information related to leases was as follows: 2021 2020 Other information: Weighted average remaining lease term - Operating leases (in years) 7.14 8.22 Weighted average remaining lease term - Finance leases (in years) 5.88 8.20 Weighted average discount rate - Operating leases 5.9 % 6.1 % Weighted average discount rate - Finance leases 4.6 % 5.1 % Maturities of lease liabilities were as follows: (In thousands) Operating Leases Finance Year Ending December 31: 2022 $ 30,347 $ 4,483 2023 24,959 4,311 2024 18,612 3,901 2025 12,923 2,834 2026 8,641 1,733 After 2026 31,890 3,078 Total lease payments 127,372 20,340 Less: Imputed interest (27,211) (2,848) Total lease liabilities $ 100,161 $ 17,492 The Company's leases, excluding short-term leases, have remaining terms of less than one year to 29 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 December 31, 2021, the Company has additional operating leases for property and equipment that have not yet commenced, with estimated ROU assets and lease liabilities of approximately $17 million to be recognized upon anticipated lease commencements in the first and second quarters of 2022. There are no material residual value guarantees or material restrictive covenants in any of the Company's leases.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Pension Benefits The Company has defined benefit pension plans covering a certain number of employees. The defined benefits for salaried employees generally are based on years of service and the employee's level of compensation during specified periods of employment. Defined benefit pension plans covering hourly employees generally provide benefits of stated amounts for each year of service. MEPPs in which the Company participates provide benefits to certain unionized employees. The Company's funding policy for qualified plans is consistent with statutory regulations and customarily equals the amount deducted for income tax purposes. Periodic voluntary contributions are made, as recommended, by the Company's Pension Committee. For most U.S. defined benefit pension plans and a majority of international defined benefit pension plans, accrued service is no longer granted. In place of these plans, the Company has established defined contribution plans providing for the Company to contribute a specified matching amount for participating employees' contributions to the plan. For U.S. employees, this match is made on employee contributions up to 4% of eligible compensation. Additionally, the Company may provide a discretionary contribution for eligible employees. There have been no discretionary contributions provided for the years 2021, 2020 and 2019. For non-U.S. employees, this match is up to 6% of eligible compensation with an additional 2% going towards insurance and administrative costs. NPPC from continuing operations for U.S. and international plans for 2021, 2020 and 2019 is as follows: U.S. Plans International Plans (In thousands) 2021 2020 2019 2021 2020 2019 Net Periodic Pension Cost (Income): Defined benefit pension plans: Service cost $ — $ — $ 39 $ 1,805 $ 1,642 $ 1,308 Interest cost 4,813 7,381 10,551 12,652 17,599 22,148 Expected return on plan assets (12,199) (11,368) (10,297) (45,018) (41,013) (37,218) Recognized prior service costs — — — 582 512 326 Recognized losses 5,538 5,100 5,585 18,119 14,723 14,345 Settlement/curtailment loss (gain) — — 129 (6) 18 19 Defined benefit pension plan cost (income) (1,848) 1,113 6,007 (11,866) (6,519) 928 Multiemployer pension plans 640 620 727 1,035 969 1,167 Defined contribution plans 5,660 4,769 2,523 4,196 3,994 5,349 Net periodic pension cost (income) $ 4,452 $ 6,502 $ 9,257 $ (6,635) $ (1,556) $ 7,444 The change in the financial status of the defined benefit pension plans and amounts recognized on the Consolidated Balance Sheets at December 31, 2021 and 2020 are as follows: U.S. Plans International Plans (In thousands) 2021 2020 2021 2020 Change in benefit obligation: Benefit obligation at beginning of year $ 296,660 $ 294,693 $ 1,119,552 $ 984,665 Service cost — — 1,805 1,642 Interest cost 4,813 7,381 12,652 17,599 Plan participants' contributions — — 15 18 Amendments — — — 1,088 Actuarial (gain) loss (8,063) 25,212 (58,567) 129,410 Settlements/curtailments — — (269) (256) Benefits paid (16,403) (17,675) (39,831) (43,952) Effect of foreign currency — — (13,159) 29,379 Acquisitions/divestitures — (12,951) — (41) Benefit obligation at end of year $ 277,007 $ 296,660 $ 1,022,198 $ 1,119,552 Change in plan assets: Fair value of plan assets at beginning of year $ 226,125 $ 226,268 $ 957,177 $ 860,321 Actual return on plan assets 19,005 24,975 40,382 95,132 Employer contributions 4,219 3,528 25,077 21,955 Plan participants' contributions — — 15 18 Settlements/curtailments — — (269) (256) Benefits paid (16,402) (17,675) (39,220) (43,527) Effect of foreign currency — — (9,910) 23,534 Acquisitions/divestitures — (10,971) — — Fair value of plan assets at end of year $ 232,947 $ 226,125 $ 973,252 $ 957,177 Funded status at end of year $ (44,060) $ (70,535) $ (48,946) $ (162,375) Significant items impacting actuarial gains and losses for 2021 for U.S. plans included: improvement in the funded position due to the actual return on the fair value of plan assets since the prior measurement date being greater than assumed, and an increase in the discount rate used to measure the benefit obligation compared with the prior year; partially offset by a decrease in the funded position due to updates in the mortality improvement projection assumption. The significant item impacting actuarial gains and losses for 2021 for international plans, principally the U.K. plan, was improvement in the funded position due to an increase in the discount rate used to measure the benefit obligation compared with the prior year. Amounts recognized on the Consolidated Balance Sheets for defined benefit pension plans consist of the following at December 31, 2021 and 2020: U.S. Plans International Plans December 31 December 31 (In thousands) 2021 2020 2021 2020 Noncurrent assets $ — $ — $ 2,046 $ — Current liabilities 1,999 1,970 967 907 Noncurrent liabilities 42,061 68,565 50,025 161,468 AOCI 114,874 135,281 410,114 487,682 Amounts recognized in AOCI for defined benefit pension plans consist of the following at December 31, 2021 and 2020: U.S. Plans International Plans (In thousands) 2021 2020 2021 2020 Net actuarial loss $ 114,874 $ 135,281 $ 400,497 $ 477,238 Prior service cost — — 9,617 10,444 Total $ 114,874 $ 135,281 $ 410,114 $ 487,682 The Company's estimate of expected contributions to be paid in 2022 for the U.S. and international defined benefit plans total $2.0 million and $24.7 million, respectively. Future Benefit Payments Expected benefit payments for defined benefit pension plans over the next ten years are as follows: (In millions) 2022 2023 2024 2025 2026 2026-2030 U.S. Plans $ 27.2 $ 16.7 $ 16.6 $ 16.5 $ 16.4 $ 78.7 International Plans 40.9 41.9 43.1 44.5 45.9 245.3 Net Periodic Pension Cost and Defined Benefit Pension Obligation Assumptions The weighted-average actuarial assumptions used to determine the defined benefit pension plan NPPC for 2021, 2020 and 2019 were as follows: U.S. Plans International Plans Global Weighted-Average 2021 2020 2019 2021 2020 2019 2021 2020 2019 Discount rates 2.4 % 3.2 % 4.2 % 1.4 % 2.1 % 2.9 % 1.6 % 2.4 % 3.2 % Expected long-term rates of return on plan assets 6.8 % 7.0 % 7.3 % 4.7 % 5.2 % 5.5 % 5.1 % 5.6 % 5.9 % The expected long-term rates of return on defined benefit pension plan assets for the 2022 NPPC are 6.3% for the U.S. plans and 4.4% for the international plans. The expected global long-term rate of return on assets for 2022 is 4.7%. The weighted-average actuarial assumptions used to determine the defined benefit pension plan obligations at December 31, 2021 and 2020 were as follows: U.S. Plans International Plans Global Weighted-Average December 31 December 31 December 31 2021 2020 2021 2020 2021 2020 Discount rates 2.7 % 2.4 % 1.9 % 1.4 % 2.1 % 1.6 % Since accrued service is no longer granted to the U.S. defined benefit plans and the majority of the international defined benefit pension plans, the rate of compensation increase did not have a significant impact on the defined benefit pension obligation at December 31, 2021 and 2020 or the defined benefit pension plan NPPC for the years ended 2021, 2020 and 2019. The U.S. discount rate was determined using a yield curve that was produced from a universe containing approximately 1,100 U.S. dollar-denominated, AA-graded corporate bonds, all of which were noncallable (or callable with make-whole provisions) and excluding the 10% of the bonds with the highest deviation from the expected yield and the 10% with the lowest deviation from the expected yield within each duration group. The discount rate was then developed as the level-equivalent rate that would produce the same present value as that using spot rates to discount the projected benefit payments. For international plans, the discount rate is aligned to corporate bond yields in the local markets, normally AA-rated corporations. The process and selection seek to approximate the cash inflows with the timing and amounts of the expected benefit payments. Accumulated Benefit Obligation The accumulated benefit obligation for all defined benefit pension plans at December 31, 2021 and 2020 was as follows: U.S. Plans International Plans December 31 December 31 (In millions) 2021 2020 2021 2020 Accumulated benefit obligation $ 277.0 $ 296.7 $ 1,016.1 $ 1,113.4 Defined Benefit Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for defined benefit pension plans with accumulated benefit obligations in excess of plan assets at December 31, 2021 and 2020 were as follows: U.S. Plans International Plans December 31 December 31 (In millions) 2021 2020 2021 2020 Projected benefit obligation $ 277.0 $ 296.7 $ 988.6 $ 1,115.7 Accumulated benefit obligation 277.0 296.7 984.7 1,109.8 Fair value of plan assets 232.9 226.1 939.3 953.5 The asset allocations attributable to the Company's U.S. defined benefit pension plans at December 31, 2021 and 2020, and the long-term target allocation of plan assets, by asset category, are as follows: Target Long-Term Percentage of Plan Assets U.S. Plans Asset Category 2021 2020 Domestic equity securities 18%-28% 22.8 % 30.8 % International equity securities 17%-27% 22.5 % 26.5 % Fixed income securities 41%-51% 45.9 % 33.4 % Cash and cash equivalents Less than 5% — % 0.7 % Other (a) 4%-14% 8.8 % 8.6 % (a) Investments within this caption include diversified global asset allocation funds and credit collection funds. Defined benefit pension plan assets are allocated among various categories of equities, fixed income securities and cash and cash equivalents with professional investment managers whose performance is actively monitored. The primary investment objective is long-term growth of assets in order to meet present and future benefit obligations. The Company periodically conducts an asset/liability modeling study and accordingly adjusts investments among and within asset categories to ensure the long-term investment strategy is aligned with the profile of benefit obligations. The Company reviews the long-term expected return on asset assumption on a periodic basis considering a variety of factors including historical investment returns achieved over a long-term period, the targeted allocation of plan assets and future expectations based on a model of asset returns for an actively managed portfolio. The model simulates 1,000 different capital market results over 20 years. The expected return-on-asset assumption for U.S. defined benefit pension plans for 2022 and 2021 are 6.3% and 6.8%, respectively. The U.S. defined benefit pension plans' assets include 310,000 shares at December 31, 2021 and 330,000 shares at December 31, 2020 of the Company's common stock, valued at $5.2 million and $5.9 million, respectively. These shares represented 2.2% and 2.6% of total U.S. plan assets at December 31, 2021 and 2020, respectively. The asset allocations attributable to the Company's international defined benefit pension plans at December 31, 2021 and 2020 and the long-term target allocation of plan assets, by asset category, are as follows: International Plans Asset Category Target Long-Term Percentage of Plan Assets 2021 2020 Equity securities 26.5 % 27.9 % 32.0 % Fixed income securities 65.5 % 63.6 % 49.5 % Cash and cash equivalents — 0.7 % 0.2 % Other (b) 8.0 % 7.8 % 18.3 % (b) Investments within this caption include diversified growth funds and real estate funds. International defined benefit pension plan assets at December 31, 2021 in the U.K. defined benefit pension plan totaled approximately 96% of the international defined benefit pension plan assets. The U.K. plan assets are allocated among various categories of equities, fixed income securities and cash and cash equivalents with professional investment managers whose performance is actively monitored. The primary investment objective is long-term growth of assets in order to meet present and future benefit obligations. The Company periodically conducts asset/liability modeling studies and accordingly adjusts investment amounts within asset categories to ensure the long-term investment strategy is aligned with the profile of benefit obligations. For the international long-term rate of return assumption, the Company considered the current level of expected returns in risk-free investments (primarily government bonds), the historical level of the risk premium associated with other asset classes in which the portfolio is invested, and the expectations for future returns of each asset class and plan expenses. The expected return for each asset class is then weighted based on the target asset allocation to develop the expected long-term rate of return on assets. The expected return on asset assumption for the U.K. defined benefit pension plan for 2022 and 2021 are 4.3% and 4.7%, respectively. The remaining international defined benefit pension plans, with plan assets representing approximately 4% of the international defined benefit pension plan assets, are under the guidance of professional investment managers and have similar investment objectives. The fair values of the Company's U.S. defined benefit pension plans' assets at December 31, 2021 by asset class are as follows: (In thousands) Total Level 1 Investments Valued at Net Asset Value (c) Domestic equities: Common stocks $ 5,180 $ 5,180 $ — Mutual funds—equities 48,411 48,411 — International equities: Mutual funds—equities 50,783 50,783 — Fixed income investments: Mutual funds—bonds 105,114 105,114 — Other—mutual funds 9,371 9,371 — Cash and money market accounts 1,624 1,624 — Other—partnerships/joint ventures 12,464 — 12,464 Total $ 232,947 $ 220,483 $ 12,464 (c) Certain investments that are measured at fair value using Net Asset Value per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The fair values of the Company's U.S. defined benefit pension plans' assets at December 31, 2020 by asset class are as follows: (In thousands) Total Level 1 Investments Valued at Net Asset Value Domestic equities: Common stocks $ 5,934 $ 5,934 $ — Mutual funds—equities 63,651 63,651 — International equities: Mutual funds—equities 59,933 59,933 — Fixed income investments: Mutual funds—bonds 75,441 75,441 — Other—mutual funds 8,944 8,944 — Cash and money market accounts 1,691 1,691 — Other - partnerships/joint ventures 10,531 — 10,531 Total $ 226,125 $ 215,594 $ 10,531 The fair values of the Company's international defined benefit pension plans' assets at December 31, 2021 by asset class are as follows: (In thousands) Total Level 1 Level 2 Equity securities: Mutual funds—equities $ 271,811 $ — $ 271,811 Fixed income investments: Mutual funds—bonds 613,243 — 613,243 Insurance contracts 5,684 — 5,684 Other: Other mutual funds 75,651 — 75,651 Cash and money market accounts 6,863 6,863 — Total $ 973,252 $ 6,863 $ 966,389 The fair values of the Company's international defined benefit pension plans' assets at December 31, 2020 by asset class are as follows: (In thousands) Total Level 1 Level 2 Equity securities: Mutual funds—equities $ 306,959 $ — $ 306,959 Fixed income investments: Mutual funds—bonds 467,285 — 467,285 Insurance contracts 6,282 — 6,282 Other: Other mutual funds 174,921 — 174,921 Cash and money market accounts 1,730 1,730 — Total $ 957,177 $ 1,730 $ 955,447 Following is a description of the valuation methodologies used for the defined benefit pension plans' investments measured at fair value: • Level 1 Fair Value Measurements—Investments in interest-bearing cash are stated at cost, which approximates fair value. The fair values of money market accounts and certain mutual funds are based on quoted net asset values of the shares held by the plan at year-end. The fair values of domestic and international stocks and corporate bonds, notes and convertible debentures are valued at the closing price reported in the active market on which the individual securities are traded. • Level 2 Fair Value Measurements—The fair values of investments in mutual funds for which quoted net asset values in an active market are not available are valued by the investment advisor based on the current market values of the underlying assets of the mutual fund based on information reported by the investment consistent with audited financial statements of the mutual fund. Further information concerning these mutual funds may be obtained from their separate audited financial statements. Investments in U.S. Treasury notes and collateralized securities are valued based on yields currently available on comparable securities of issuers with similar credit ratings. Multiemployer Pension Plans

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Current income tax expense or benefit represents the amounts expected to be reported on the Company's income tax returns, and deferred income tax expense or benefit represents the change in net deferred tax assets and liabilities. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities as measured by the enacted income tax rates that will be in effect when these differences reverse. Valuation allowances are recorded as appropriate to reduce deferred tax assets to the amount considered more likely than not to be realized. Included in the Tax Act were the global intangible low-taxed income ("GILTI") provisions. The Company elected to account for GILTI tax in the period in which it is incurred. The GILTI provisions require the Company to include in its U.S. income tax return foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary's tangible assets. Income (loss) from continuing operations before income taxes and equity income as reported on the Consolidated Statements of Operations consists of the following: (In thousands) 2021 2020 2019 U.S. $ (34,462) $ (87,315) $ (38,969) International 71,968 33,095 70,034 Total income (loss) from continuing operations before income taxes and equity income $ 37,506 $ (54,220) $ 31,065 Income tax expense (benefit) as reported on the Consolidated Statements of Operations consists of the following: (In thousands) 2021 2020 2019 Income tax expense (benefit): Currently payable: U.S. federal $ — $ (12,116) $ 902 U.S. state 507 468 220 International 22,295 16,518 21,132 Total income taxes currently payable 22,802 4,870 22,254 Deferred U.S. federal (4,594) (10,558) (9,367) Deferred U.S. state (18) (3,078) (2,575) Deferred international (9,101) 93 2,416 Total income tax expense (benefit) from continuing operations $ 9,089 $ (8,673) $ 12,728 Cash payments for income taxes were $21.7 million, $34.9 million and $115.6 million for 2021, 2020 and 2019, respectively. The decrease in cash payments for 2021 is principally due to payments associated with the gain on the sale of IKG in 2020 and the gain on the sale of AXC and PK in 2019 not recurring in 2021. A reconciliation of the normal expected statutory U.S. federal income tax expense (benefit) to the actual Income tax expense (benefit) from continuing operations as reported on the Consolidated Statements of Operations is as follows: (In thousands) 2021 2020 2019 U.S. federal income tax expense (benefit), at statutory tax rate of 21% $ 7,877 $ (11,386) $ 6,523 U.S. state income taxes, net of federal income tax benefit (310) (2,015) (1,290) U.S. other domestic deductions and credits (415) (1,312) (596) Difference in effective tax rates on international earnings and remittances 4,488 7,872 7,536 Uncertain tax position contingencies and settlements 783 289 310 Changes in realization on beginning of the year deferred tax assets (5,035) (1,501) 2,343 U.S. non-deductible expenses 936 2,300 2,461 Impact of U.S. tax reform — — 1,644 Net operating loss carryback (2,696) — State deferred tax rate changes 592 (40) (3,354) Employee share-based payments 173 (184) (2,817) Other, net — — (32) Total income tax expense (benefit) from continuing operations $ 9,089 $ (8,673) $ 12,728 At December 31, 2021, 2020 and 2019, the Company's annual effective income tax rate on income (loss) from continuing operations was 24.2%, 16.0% and 41.0%, respectively. The Company’s international income from continuing operations before income taxes and equity income was $72 million and $33.1 million for 2021 and 2020, respectively. In 2021, the Company recorded $6.8 million income tax benefit arising from the recognition of deferred tax assets in Harsco Environmental Brazil. Brazil has 3 years of cumulative income and expects to utilize the deferred tax assets against future income. The Company's total international income tax expense decreased from $16.6 million in 2020 to $13.2 million in 2021 primarily due to the Brazil income tax benefit in 2021, partially offset by improvement of operating income. The Company’s differences in income tax expense for 2021 and 2020 on international earnings and remittances was $4.5 million and $7.9 million, respectively, which included U.S income tax expense on international deemed remittances of $0.1 million and $0.1 million respectively. The decrease is primarily due to the change in mix of income. The Company's U.S. loss from continuing operations before income taxes and equity income was $34.5 million and $87.3 million for 2021 and 2020, respectively. The Company's total U.S. income tax benefit decreased from $25.3 million in 2020 to $4.1 million in 2021 primarily due to decreased expenses from corporate strategic spending, recognition of net operating loss carrybacks not recurring in 2021, as well as disallowed interest expense. The income tax effects of the temporary differences giving rise to the Company's deferred tax assets and liabilities at December 31, 2021 and 2020 are as follows: 2021 (a) 2020 (a) (In thousands) Asset Liability Asset Liability Depreciation and amortization $ — $ 80,278 $ — $ 87,681 Right-of-use assets 25,759 23,406 Operating lease liabilities 25,431 22,868 Expense accruals 24,949 — 22,136 — Inventories 3,400 — 2,721 — Provision for receivables 5,504 — 4,903 — Deferred revenue — 4,124 — 4,425 Operating loss carryforwards 65,935 — 66,703 — Tax credit carryforwards 18,608 — 15,630 — Pensions 23,298 — 49,740 — Currency adjustments 5,075 — 4,829 — Deferred financing costs 359 — — 269 Section 163(j) disallowed interest expense 4,843 — — — Post-retirement benefits 335 — 340 — Stock based compensation 7,396 — 6,696 — Other 1,470 — 1,954 — Subtotal 186,603 110,161 198,520 115,781 Valuation allowance (92,385) — (108,563) — Total deferred income taxes $ 94,218 $ 110,161 $ 89,957 $ 115,781 (a) Does not include approximately $1.1 billion of statutory loss carryforwards within Luxembourg for which the Company considers the utilization of these attributes remote and as such no deferred tax asset or corresponding valuation allowance has been recorded. At December 31, 2021, the tax-effected amount of NOLs totaled $65.9 million. Tax-effected NOLs from international operations are $40.9 million. Of that amount, $32.0 million can be carried forward indefinitely and $8.9 million will expire at various times between 2022 and 2041. Tax-effected U.S. state NOLs are $16.0 million. Of that amount, $3.6 million expire at various times between 2022 and 2026, $3.2 million expire at various times between 2027 and 2031, $4.7 million expire at various times between 2032 and 2036 and $4.5 million expire at various times between 2037 and 2041. At December 31, 2021, the tax-effected amount of U.S. Federal NOLs totaled $9.0 million. Of that amount, $7.2 million can be carried forward indefinitely and $1.8 million will expire at various times between 2033 and 2034. Valuation allowances of $92.4 million and $108.6 million at December 31, 2021 and 2020, respectively, related principally to deferred tax assets for pension liabilities, NOLs, foreign tax credit carryforwards and foreign currency translation that are uncertain as to realizability. In 2021, the Company recorded a valuation allowance reduction of $19.3 million related to current year pension adjustment recorded through AOCI, a valuation allowance reduction of $6.8 million in Brazil where the Company determined that it is more likely than not that these assets will be realized, and a valuation allowance reduction of $3.5 million from the effects of foreign currency translation adjustments, partially offset by a $14.4 million valuation allowance increase related to the UK tax rate change, and $4.8 million valuation allowance increase related to disallowed interest expense. The Tax Act introduced a transition tax and a territorial tax system, which was effective beginning in 2018. The territorial tax system impacts the Company's overall global capital and legal entity structure, working capital, and repatriation plan on a go-forward basis. The Company asserts that all foreign earnings will be indefinitely reinvested to meet local cash needs. The Company therefore intends to limit distributions to earnings previously taxed in the U.S., or earnings that would qualify for the 100 percent dividends received deduction provided for in the Tax Act, and earnings that would not result in any significant foreign taxes. Therefore, the Company has not recognized a deferred tax liability on its investment in foreign subsidiaries. The Company recognizes accrued interest and penalty expense related to unrecognized income tax benefits in income tax expense or benefit. The Company recognized an income tax expense of $0.4 million, $0.2 million and $0.3 million during 2021, 2020 and 2019, respectively, for interest and penalties. The Company has accrued $1.7 million, $1.4 million and $1.2 million for the payment of interest and penalties at December 31, 2021, 2020 and 2019, respectively. A reconciliation of the change in the unrecognized income tax benefits balance from January 1, 2019 to December 31, 2021 is as follows: (In thousands) Unrecognized Deferred Unrecognized Balances, January 1, 2019 $ 2,422 $ (26) $ 2,396 Additions for tax positions related to the current year (includes currency translation adjustment) 414 (7) 407 Additions for tax positions related to prior years (includes currency translation adjustment) 681 — 681 Statutes of limitation expirations (326) 2 (324) Settlements (62) 9 (53) Balance at December 31, 2019 3,129 (22) 3,107 Additions for tax positions related to the current year (includes currency translation adjustment) 596 (2) 594 Other reductions for tax positions related to prior years (771) — (771) Statutes of limitation expirations (58) 2 (56) Balance at December 31, 2020 2,896 (22) 2,874 Additions for tax positions related to the current year (includes currency translation adjustment) 316 (1) 315 Additions for tax positions related to prior years (includes currency translation adjustment) 500 — 500 Statutes of limitation expirations (585) 1 (584) Total unrecognized income tax benefits that, if recognized, would impact the effective income tax rate at December 31, 2021 $ 3,127 $ (22) $ 3,105 Within the next twelve months, it is reasonably possible that up to $0.4 million of unrecognized income tax benefits will be recognized upon settlement of income tax examinations and the expiration of various statutes of limitations. The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. With few exceptions, the Company is no longer subject to U.S and international income tax examinations by tax authorities through 2015.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
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) December 31 December 31 Current portion of environmental liabilities (a) $ 7,338 $ 6,862 Long-term environmental liabilities 28,435 29,424 Total environmental liabilities $ 35,773 $ 36,286 (a) The current portion of environmental liabilities is included in the caption Other current liabilities on the 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. Legal Proceedings In the ordinary course of business, the company is a defendant or party to various claims and lawsuits, including those discussed below. On March 28, 2018, the United States Environmental Protection Agency (the “EPA”) conducted an inspection of ESOL’s off-site waste management facility in Detroit, MI. On November 23, 2021, the EPA proposed a civil penalty of $390,092 as part of a proposed Administrative Consent Order for alleged improper air emissions at the site. The allegations in the proposed Administrative Consent Order and civil penalty relate exclusively to the period prior the Company’s purchase of the ESOL business. The Company is vigorously contesting the allegations. The Company believes that any loss related to this issue will be recoverable under indemnity rights under the ESOL purchase agreement and representations and warranties insurance policies purchased by the Company, subject to applicable deductibles. On January 27, 2020, the U.S. EPA issued a Notice of Potential Liability to the Company, along with several other companies, concerning the Newtown Creek Superfund Site located in Kings and Queens Counties in New York. The Notice alleges certain facilities formerly owned or operated by subsidiaries of the Company may have resulted in the discharge of hazardous substances into Newtown Creek or its Dutch Kills tributary. The site has been subject to CERCLA response activities since approximately 2011. The U.S. EPA expects to propose a sitewide cleanup plan no sooner than 2024 and announced in July 2021 that it would defer its decision on a potential early action response for the lower two miles of the Creek until the sitewide studies are completed. The Company is one of approximately twenty (20) Potentially Responsible Parties that have received notices, though it is believed other PRPs may exist. The Company vigorously contests the allegations of the Notice and currently does not believe that this matter will have a material effect on the Company’s financial position or results from operations. 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. On September 28, 2021, DTSC scheduled a public hearing on October 28, 2021 as part of its Violation Scoring Procedure (VSP) program to hear testimony on the compliance tier assignment assigned to the facility. The Company would have the ability to judicially challenge any adverse permit actions resulting from this process. The DTSC investigation and compliance issues leading to the compliance tier assignment were 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 and public hearing process 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. 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. Commissioning of the facilities was completed during the third quarter of 2021 and the processing of the salt cakes has commenced. The Company has previously established a reserve of $7.5 million, which continues to represent 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 $1 thousand per day) and CSN 20,000 Brazilian reais per day (or approximately $4 thousand 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 $5 thousand per day) and raising the fines assessed to CSN to 100,000 Brazilian reais per day (or approximately $20 thousand per day). The Court also assessed an additional fine of 10,000,000 Brazilian reais (or approximately $2 million) 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 alleged violations of the Company’s environmental permit at the site, which restricts the release of any visible dust emissions. On January 12, 2022, the Administrative Supreme Court upheld the Company’s challenge of these enforcement actions as they relate to the slag tipping area of the site. As a result, all fines asserted against the Company to date have been invalidated and all fines paid to date must be reimbursed. This order is not appealable. On or about October 14, 2021, the Company received a subpoena and two indictments on this matter before the Amsterdam District Court in the Netherlands. The Amsterdam Public Prosecutor’s Office issued the two indictments against the Company, alleging violations in connection with dust releases and/or events alleged to have occurred in 2018 through May 2020 at the site. The action cites provisions which permit fines for the alleged infractions and seeks EURO 100,000 in fines with a smaller amount held in abeyance. On February 2, 2022, the prosecutor announced that they would further investigate residents’ claims related to this matter. The Company is vigorously contesting all allegations against it and is also working with its customer to ensure the control of emissions. The Company has contractual indemnity rights from its customer that it believes will substantially cover any fines or penalties. 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 December 31, 2021, the principal amount of the tax assessment from the SPRA with regard to this case is $1.1 million, with penalty, interest and fees assessed to date increasing such amount by an additional $15.4 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 $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 $7 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 $5 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. On December 30, 2020, the Company received an assessment from the municipal authority in Ipatinga, Brazil alleging $1.9 million in unpaid service taxes from the period 2015 to 2020. After calculating the interest and penalties accrued, the Company estimates that the current overall potential liability for this case to be approximately $3 million. On January 18, 2021, the Company filed a challenge to the assessment. Due to the multiple defenses that are available, the Company does not believe a loss is probable. 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 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 December 31, 2021 and 2020, the Company has established reserves of $3.2 million and $4.3 million, respectively, on the Consolidated Balance Sheets for amounts considered to be probable and estimable. 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 December 31, 2021, there were approximately 17,240 pending asbestos personal injury actions filed against the Company. Of those actions, approximately 16,610 were filed in the New York Supreme Court (New York County), approximately 120 were filed in other New York State Supreme Court Counties and approximately 510 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 December 31, 2021, 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 60 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 December 31, 2021, the Company has obtained dismissal in approximately 28,360 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 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 Insurance claim receivable and Other receivables on the Consolidated Balance Sheets. See Note 1, Summary of Significant Accounting Policies, for additional information on Accrued insurance and loss reserves.

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Capital Stock	Capital Stock The authorized capital stock of the Company consists of 150,000,000 shares of common stock and 4,000,000 shares of preferred stock, both having a par value of $1.25 per share. The preferred stock is issuable in series with terms as fixed by the Board. No preferred stock has been issued. The following table summarizes the Company's common stock: Shares Treasury Outstanding Outstanding, January 1, 2019 113,473,951 33,928,928 79,545,023 Shares issued for vested restricted stock units 321,965 125,863 196,102 Shares issued for vested performance units 908,566 379,353 529,213 Stock appreciation rights exercised 15,865 4,619 11,246 Treasury shares purchased — 1,766,826 (1,766,826) Outstanding, December 31, 2019 114,720,347 36,205,589 78,514,758 Shares issued for vested restricted stock units 229,413 91,188 138,225 Shares issued for vested performance stock units 471,412 206,261 265,151 Stock appreciation rights exercised 8,870 2,634 6,236 Outstanding, December 31, 2020 115,430,042 36,505,672 78,924,370 Shares issued for vested restricted stock units 305,535 112,275 193,260 Shares issued for vested performance stock units 124,077 54,950 69,127 Stock appreciation rights exercised 46,739 17,950 28,789 Outstanding, December 31, 2021 115,906,393 36,690,847 79,215,546 (a) The Company repurchases shares in connection with the issuance of shares under stock-based compensation programs and in accordance with Board authorized share repurchase programs. The following is a reconciliation of the average shares of common stock used to compute basic earnings per common share to the shares used to compute diluted earnings per common share as shown on the Consolidated Statements of Operations: (In thousands, except per share data) 2021 2020 2019 Income (loss) from continuing operations attributable to Harsco Corporation common stockholders $ 22,137 $ (49,727) $ 10,311 Weighted-average shares outstanding—basic 79,234 78,939 79,632 Dilutive effect of stock-based compensation 1,055 — 1,743 Weighted-average shares outstanding—diluted 80,289 78,939 81,375 Income (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders: Basic $ 0.28 $ (0.63) $ 0.13 Diluted $ 0.28 $ (0.63) $ 0.13 The following average outstanding stock-based compensation units were not included in the computation of diluted earnings per share because the effect was antidilutive or the market conditions for the performance share units were not met: (In thousands) 2021 2020 2019 Restricted stock units — 714 — Stock appreciation rights 826 2,474 491 Performance share units 865 887 124

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The 2013 Equity and Incentive Plan as amended (the "2013 Plan") authorizes the i ssuance of up to 9.9 million shares of the Company's common stock for use in paying incentive compensation awards in the form of stock options or other equity awards such as restricted stock, restricted stock units ("RSUs"), stock appreciation rights ("SARs") or performance share units ("PSUs"). Of the 9.9 million shares authorized, a maximum of 6.5 million shares may be issued for awards other than option rights or SARs, as defined in the 2013 Plan. The 2016 Non-Employee Directors' Long-Term Equity Compensation Plan, as amended (the "2016 Plan") authorizes the issuance of up to 800 thousand shares of the Company's common stock for equity awards. Both plans have been approved by the Company's stockholders. At December 31, 2021, there were 2.4 million shares available for granting equity awards under the 2013 Plan, of which 1.8 million shares were available for awards other than option rights or SARs. At December 31, 2021, there were 430 thousand shares available for granting equity awards under the 2016 Plan. Restricted Stock Units The Board approves the granting of performance-based RSUs as the long-term equity component of director, officer and certain key employee compensation. The RSUs require no payment from the recipient and compensation cost is measured based on the market price of the Company's common stock on the grant date and is generally recorded over the vesting period. RSUs granted to officers and certain key employees in 2019, 2020 and 2021 either vest on a pro-rata basis over three years or upon obtainment of specified retirement or years of service criteria. The vesting period for RSUs granted to non-employee directors is one year and each RSU is exchanged for an equal number of shares of the Company's common stock upon vesting for awards issued under the 2016 Plan and following the termination of the participant's service as a director under prior plans. RSUs do not have an option for cash payment. The following table summarizes RSUs issued and the compensation expense from continuing operations recorded for the years ended December 31, 2021, 2020, and 2019: RSUs (a) Weighted Average Fair Value Expense (Dollars in thousands, except per unit) 2021 2020 2019 Directors: 2018 43,821 20.54 — — 280 2019 14,211 25.33 — 120 240 2020 34,986 10.29 120 240 — 2021 23,224 21.53 333 — — Employees: 2016 536,773 7.09 — — 245 2017 286,251 13.70 — 85 763 2018 242,791 19.93 142 706 1,064 2019 270,864 22.25 1,239 1,270 1,524 2020 522,087 8.22 1,093 1,244 — 2021 343,125 18.62 1,892 — — Total $ 4,819 $ 3,665 $ 4,116 (a) Represents number of awards originally issued. RSU activity for the year ended December 31, 2021 was as follows: Number of Shares Weighted Average Non-vested at December 31, 2020 686,287 $ 11.84 Granted 366,349 18.81 Vested (307,543) 13.33 Forfeited (32,249) 14.16 Non-vested at December 31, 2021 712,844 14.68 At December 31, 2021, the total unrecognized compensation expense related to non-vested RSUs was $6.0 million, which will be recognized over a weighted-average period of 1.9 years . The total fair value of RSU's vested in 2021, 2020 and 2019 was $4.1 million, $4.3 million and $4.7 million, respectively. Stock Appreciation Rights The Board approves the granting of SARs to officers and certain key employees under the 2013 Plan. The SARs generally vest on a pro-rata three During 2019, the Company issued SARS covering 216,100 shares in March and 13,244 shares in July under the 2013 Plan. During 2020, the Company issued SARS covering 785,152 shares in March and 20,526 in October under the 2013 Plan. During 2021, the Company issued SARS covering 184,641 shares in March under the 2013 Plan. The fair value of each SAR grant was estimated on the grant date using a Black-Scholes pricing model with the following assumptions: Risk-free Interest rate Dividend Yield Expected Life (Years) Volatility SAR Grant Price Fair Value of SAR March 2019 Grant 2.52 % — % 6.0 46.2 % 22.51 10.62 July 2019 Grant 1.84 % — % 6.0 47.1 % 27.39 12.80 March 2020 Grant 0.76 % — % 6.0 45.2 % 10.29 3.03 October 2020 Grant 0.44 % — % 6.0 60.3 % 14.89 8.12 March 2021 Grant 0.91 % — % 6.0 61.9 % 18.58 10.48 The March 2020 Grant's fair value was estimated using a Monte Carlo simulation because the exercise price is greater than the fair value of Harsco common stock on the grant date. SARs activity for the year ended December 31, 2021 was as follows: Number of Shares Weighted Average Exercise Price Aggregate Intrinsic Value (in millions) (b) Outstanding, December 31, 2020 2,401,131 $ 14.37 $ 11.7 Granted 184,641 18.58 Exercised (107,413) 10.81 Forfeited/Expired (84,304) 17.31 Outstanding, December 31, 2021 2,394,055 14.75 8.6 (b) Intrinsic value is defined as the difference between the current market value and the exercise price, for those SARs where the market price exceeds the exercise price. The total intrinsic value of SARs exercised in 2021, 2020 and 2019 was $0.6 million, $0.5 million, and $0.3 million, respectively. The following table summarizes information concerning outstanding and exercisable SARs at December 31, 2021: SARs Outstanding SARs Exercisable Range of exercisable prices Vested Non-vested Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Life in Years Number Exercisable Weighted-Average Exercise Price per Share $7.00 - $14.89 807,168 443,256 $ 9.87 6.53 807,168 $ 9.48 $16.53 - $22.70 727,909 221,624 19.12 5.31 727,909 19.01 $23.25 - $26.92 194,098 — 24.80 2.61 194,098 24.80 1,729,175 664,880 14.75 5.73 1,729,175 15.21 Total compensation expense from continuing operations related to SARs was $1.8 million, $1.7 million and $1.8 million for the years ended December 31, 2021, 2020 and 2019, respectively. At December 31, 2021, total unrecognized compensation expense related to non-vested SARs was $2.2 million , which will be recognized over a weighted average period of 1.8 years. Weighted-average grant date fair value of non-vested SARs for the year ended December 31, 2021 was as follows: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares, December 31, 2020 877,947 $ 4.50 Granted 184,641 10.48 Vested (348,340) 5.33 Forfeited (49,368) 5.77 Non-vested shares, December 31, 2021 664,880 5.63 Performance Share Units The Board approves the granting of PSUs to officers and certain key employees that may be earned based on the Company's total shareholder return over the three During the year ended December 31, 2019, the Company granted 233,112 shares in March, 6,189 shares in July and 38,006 shares in August under the 2013 Plan. During the year ended December 31, 2020, the Company granted 513,995 shares in March and 11,194 shares in October under the 2013 Plan. During the year ended December 31, 2021, the Company granted 316,959 shares in March under the 2013 Plan. The fair value of PSUs granted was estimated on the grant date using a Monte Carlo pricing model with the following assumptions: Risk-free Interest rate Dividend Yield Expected Life (Years) Volatility Fair Value of PSU March 2019 Grant 2.48 % — % 2.82 33.8 % 29.04 July 2019 Grant 1.75 % — % 2.50 34.3 % 40.07 August 2019 Grant 1.57 % — % 2.41 34.9 % 23.38 March 2020 Grant 0.56 % — % 2.81 36.0 % 4.40 October 2020 Grant 0.17 % — % 2.20 53.7 % 17.01 March 2021 Grant 0.25 % — % 2.83 50.7 % 25.38 Total compensation expense from continuing operations related to PSUs was $5.1 million, $3.2 million and $4.8 million for the years ended December 31, 2021, 2020 and 2019, respectively. At December 31, 2021, total unrecognized compensation expense related to non-vested PSUs was $5.6 million, which will be recognized over a weighted average period of 1.9 years. A summary of the Company's non-vested PSU activity during the year ending December 31, 2021 was as follows: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares, December 31, 2020 696,318 $ 11.85 Granted 316,959 25.38 Forfeited (44,839) 15.47 Vested, not issued (c) (214,645) 26.84 Non-vested shares, December 31, 2021 753,793 13.05 (c) The measurement period for PSUs issued in 2019 ended on December 31, 2021 and these shares vested but will not be issued until the Board certifies the measurement period results in early 2022. A total of 0 shares are expected to be issued.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments Off-Balance Sheet Risk As collateral for the Company's performance and to insurers, the Company is contingently liable under standby letters of credit, bonds, bank guarantees and performance guarantees in the amounts of $519.4 million, $410.6 million and $281.8 million at December 31, 2021, 2020 and 2019, respectively. The expiration periods of the standby letters of credit, bonds and bank guarantees range from less than 1 year to over 5 years. but the majority are generally in force for up to 2 years. Certain issues have no scheduled expiration date. The Company pays fees to various banks and insurance companies that range from 0.4% to 3.8% per annum of the instrument's face value. If the Company were required to obtain replacement standby letters of credit, bonds and bank guarantees at December 31, 2021 for those currently outstanding, it is the Company's opinion that the replacement costs would be within the present fee structure. The Company has currency exposures in approximately 30 countries. The Company's primary foreign currency exposures during 2021 were in the European Union, the U.K., Brazil and China. Off-Balance Sheet Risk—Third-Party Guarantees Any liabilities related to the Company's obligation to stand ready to act on third-party guarantees are included in Other current liabilities or Other liabilities (as appropriate) on the Consolidated Balance Sheets. Any recognition of these liabilities did not have a material impact on the Company's financial position or results of operations for 2021, 2020 or 2019. In the normal course of business, legal indemnifications are provided related primarily to the performance of the Company's products and services and patent and trademark infringement of the products and services sold. These indemnifications generally relate to the performance (regarding function, not price) of the respective products or services and therefore no liability is recognized related to the fair value of such guarantees. 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 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. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The Company utilizes market data or assumptions that the Company believes market participants would use in valuing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. The fair value hierarchy distinguishes between (1) market participant assumptions developed based on market data obtained from independent sources (observable inputs), and (2) an entity’s own assumptions about market participant assumptions based on the best information available in the circumstances (unobservable inputs). The fair value hierarchy consists of three broad levels, which give the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are described below: • Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. • Level 2—Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates); and inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3—Inputs that are both significant to the fair value measurement and unobservable. In instances in which multiple levels of inputs are used to measure fair value, hierarchy classification is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The fair value of outstanding derivative contracts recorded as assets and liabilities on the 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 December 31, 2021 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 719 $ 1,405 $ 2,124 Total $ 719 $ 1,405 $ 2,124 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 560 $ 2,905 $ 3,465 Interest rate swaps Other current liabilities 4,157 — 4,157 Total $ 4,717 $ 2,905 $ 7,622 (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 December 31, 2020 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 900 $ 2,777 $ 3,677 Total $ 900 $ 2,777 $ 3,677 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 950 $ 4,098 $ 5,048 Interest rate swaps Other current liabilities 3,959 — 3,959 Interest rate swaps Other liabilities 3,718 — 3,718 Total $ 8,627 $ 4,098 $ 12,725 All of the Company's derivatives are recorded on the 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 have resulted in a $0.9 million net liability at December 31, 2021 and at December 31, 2020 would not have resulted in a net asset or liability. The effect of derivative instruments on the Consolidated Statements of Operations and the Consolidated Statements of Comprehensive Income (Loss) was as follows: Derivatives Designated as Hedging Instruments Amount Recognized in Location of Amount Reclassified Amount Reclassified from (In thousands) 2021 2020 2019 2021 2020 2019 Foreign currency exchange forward contracts $ — $ — $ (41) Product revenues/Cost of services sold $ — $ — $ 44 Foreign currency exchange forward contracts 309 (930) (1,186) Income (loss) from discontinued businesses (129) (1,026) (550) Interest rate swaps — — — Income (loss) from discontinued businesses — — 2,741 Interest rate swaps (42) (3,889) (8,209) Interest expense 3,474 2,589 (520) CCIRs(a) — 39 (42) Interest expense — 1,015 1,219 $ 267 $ (4,780) $ (9,478) $ 3,345 $ 2,578 $ 2,934 (a) Amounts represent changes in foreign currency translation related to balances in AOCI. The location and amount of gain (loss) recognized on the Consolidated Statements of Operations: 2021 (in thousands) Interest Expense Income (Loss) from Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (63,235) $ (25,863) Interest rate swaps: Gain or (loss) reclassified from AOCI into income (3,474) — Gain or (loss) reclassified from AOCI into income as a result that a forecasted transaction Amount recognized in earnings due to ineffectiveness 89 — Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income — 129 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — 62 Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach — (2) 2020 (in thousands) Interest Expense Income (Loss) From Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (58,196) $ 20,350 Interest rate swaps: Gain or (loss) reclassified from AOCI into income (2,589) — Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income — 1,026 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — 197 Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach — 31 CCIRs: Gain or (loss) reclassified from AOCI into income (1,015) — 2019 (in thousands) Cost of Services Sold Interest Expense Income (Loss) From Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ 822,043 $ (34,024) $ 52,937 Interest rate swaps: Gain or (loss) reclassified from AOCI into income — 520 — Gain or (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 (44) — 550 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — — 509 CCIRs: Gain or (loss) reclassified from AOCI into income — (1,219) — Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives for the Twelve Months Ended December 31(b) (In thousands) 2021 2020 2019 Foreign currency exchange forward contracts Cost of services and products sold $ 10,761 $ (9,052) $ 6,807 (b) These gains (losses) offset amounts recognized in cost of service 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 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. The recognized gains and losses offset amounts recognized in cost of services and products sold principally as a result of intercompany or third-party foreign currency exposures. At December 31, 2021 and December 31, 2020, the notional amounts of foreign currency exchange forward contracts were $425.8 million and $460.5 million, respectively. These contracts primarily hedge British pounds sterling and euros against other currencies and mature through March 2023. 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 $2.7 million, $0.4 million and $7.7 million related to hedges of net investments during 2021, 2020 and 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. At December 31, 2021, the Company has entered into a series of interest rate swaps that are in effect through 2022 and have the effect of converting $200.0 million of the New 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 2.71% for 2021 to 3.12% for 2022. In 2019, the Company terminated certain interest rate swaps in conjunction with the issuance of its Senior Notes. The Company paid $2.8 million and recognized a loss of $2.7 million related to these terminations in Income (loss) from discontinued businesses on the Consolidated Statements of Operations. In the fourth quarter of 2021, the interest rate swaps were deemed ineffective and thus the subsequent changes in fair value were recorded in earnings in the current period. 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 in the Consolidated Statements of Operations and offset currency fluctuation effects on the debt principal. The Company had no outstanding CCIRs at December 31, 2021 or December 31, 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 December 31, 2021 and 2020, the total fair value of long-term debt, including current maturities, was $1,394.2 million and $1,324.9 million, respectively, compared with a carrying value of $1,387.9 million and $1,300.5 million, respectively. Fair values for debt are based upon pricing models using market-based inputs (Level 2) for similar issues or on the current rates offered to the Company for debt of the same remaining maturities. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. The Company places cash and cash equivalents with high-quality financial institutions and, by policy, limits the amount of credit exposure to any single institution. Concentrations of credit risk with respect to accounts receivable exist in the Company's Harsco Environmental Segment which have several large customers throughout the world with significant accounts receivable balances. Consolidation in the global steel or rail industries could result in an increase in concentration of credit risk for the Company. The Clean Earth Segment also has significant sales to several U.S. customers. The Company generally does not require collateral or other security to support customer receivables. If a receivable from one or more of the Company's larger customers becomes uncollectible, it could have a material effect on the Company's results of operations or cash flows.

Information by Segment and Geog

Information by Segment and Geographic Area	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Information by Segment and Geographic Area	Information by Segment and Geographic Area 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, services and markets served. In 2021, the Company had two reportable segments. These segments and the types of products and services offered include the following: Harsco Environmental The Segment provides environmental services and material processing to the global steel and metals industries. The Segment partners with its global customer base to deliver production-critical on-site operational support and resource recovery services, through management of its customers’ primary waste or byproduct streams. The Segment's services support the metal manufacturing process, generating significant operational and financial efficiencies for its customers and allowing them to focus on their core steelmaking businesses. In addition, this Segment creates value-added downstream products from industrial waste streams. Harsco Clean Earth The Segment is one of the largest specialty waste processing companies in the U.S., providing processing and beneficial reuse solutions for hazardous wastes, and soil and dredged materials. Other Information The measurement basis of segment profit or loss is operating income. There are no significant inter-segment sales. Corporate assets, at December 31, 2021 and 2020, include principally cash, prepaid taxes, fair value of derivative instruments and U.S. deferred income taxes. Countries with revenues from unaffiliated customers or net property, plant and equipment of ten percent or more of the consolidated totals (in at least one period presented) are as follows: Information by Geographic Area (a) Revenues from Unaffiliated Customers Twelve Months Ended December 31 (In thousands) 2021 2020 2019 U.S. $ 1,008,689 $ 830,699 $ 420,956 U.K. 117,529 116,425 126,660 All Other 722,181 586,909 656,753 Totals including Corporate $ 1,848,399 $ 1,534,033 $ 1,204,369 (a) Revenues are attributed to individual countries based on the location of the facility generating the revenue. Property, Plant and Equipment, Net December 31 (In thousands) 2021 2020 U.S. $ 267,174 $ 253,994 China 108,496 109,617 All Other 278,243 266,743 Totals including Corporate $ 653,913 $ 630,354 No customer provided in excess of 10% of the Company's consolidated revenues in 2021 and 2020. One customer provided in excess of 10% of the Company's consolidated revenues in 2019. In 2021, 2020 and 2019, the Harsco Environmental Segment had one customer that provided in excess of 10% of this Segment's revenues under multiple long-term contracts at several mill sites. Should additional consolidations occur involving some of the steel industry's larger companies which are customers of the Company, it would result in an increase in concentration of credit risk for the Company. The loss of any one of the contracts would not have a material adverse effect upon the Company's financial position or cash flows; however, it could have a significant effect on quarterly or annual results of operations. In 2021 and 2020, Harsco Clean Earth had one customer that provided in excess of 10% of the Segment's revenue and, in 2019, no customers in excess of 10% of the Segment's revenues. The loss of this customer would not have a material adverse impact on the Company's financial positions or cash flows; however, it could have a material effect on quarterly or annual results of operations. Operating Information by Segment: Twelve Months Ended December 31 (In thousands) 2021 2020 2019 Revenues ( b ) Harsco Environmental $ 1,068,083 $ 914,445 $ 1,034,847 Harsco Clean Earth 780,316 619,588 169,522 Total Revenues $ 1,848,399 $ 1,534,033 $ 1,204,369 Operating Income (Loss) ( b ) Harsco Environmental $ 103,402 $ 59,006 $ 112,298 Harsco Clean Earth 25,639 16,096 20,009 Corporate (40,665) (78,408) (55,904) Total Operating Income (Loss) $ 88,376 $ (3,306) $ 76,403 Total Assets Harsco Environmental $ 1,386,087 $ 1,322,731 $ 1,296,061 Harsco Clean Earth 1,278,472 1,279,387 745,410 Corporate 56,086 74,185 28,455 Discontinued Operations 333,263 316,984 297,541 Total Assets $ 3,053,908 $ 2,993,287 $ 2,367,467 Depreciation ( b ) Harsco Environmental $ 105,830 $ 100,971 $ 104,840 Harsco Clean Earth 19,672 17,450 4,932 Corporate 1,900 2,022 2,737 Total Depreciation $ 127,402 $ 120,443 $ 112,509 Amortization ( b ) Harsco Environmental $ 8,052 $ 7,825 $ 7,286 Harsco Clean Earth 24,180 22,814 7,923 Corporate ( c ) 2,710 2,961 2,500 Total Amortization $ 34,942 $ 33,600 $ 17,709 Capital Expenditures ( b ) Harsco Environmental $ 137,228 $ 99,056 $ 153,694 Harsco Clean Earth 18,403 12,612 5,870 Corporate 1,289 488 1,762 Total Capital Expenditures $ 156,920 $ 112,156 $ 161,326 (b) 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 Rail Segment and former Harsco Industrial Segment have been reflected as discontinued operations in the Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (c) Amortization expense on Corporate relates to the amortization of deferred financing costs. Reconciliation of Segment Operating Income to Consolidated Income (Loss) From Continuing Operations Before Income Taxes and Equity Income: Twelve Months Ended December 31 (In thousands) 2021 2020 2019 Segment operating income $ 129,041 $ 75,102 $ 132,307 General Corporate expense (40,665) (78,408) (55,904) Operating income from continuing operations 88,376 (3,306) 76,403 Interest income 2,231 2,129 1,946 Interest expense (63,235) (58,196) (34,024) Defined benefit pension income (expense) 15,640 7,073 (5,556) Unused debt commitment fees, amendment fees and loss on extinguishment of debt (5,506) (1,920) (7,704) Income (loss) from continuing operations before income taxes and equity income $ 37,506 $ (54,220) $ 31,065

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2021
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 Segment. Product revenues include portions of the Harsco Environmental Segment. See Note 1, Summary of Significant Accounting Policies, Revenue Recognition, for additional information. A summary of the Company's revenues by primary geographical markets as well as by key product and service groups is as follows: Twelve Months Ended December 31, 2021 (In thousands) Harsco Harsco Consolidated Totals Primary Geographical Markets (a)(b) : North America $ 281,124 $ 780,317 $ 1,061,441 Western Europe 442,286 — 442,286 Latin America (c) 132,349 — 132,349 Asia-Pacific 110,790 — 110,790 Middle East and Africa 81,337 — 81,337 Eastern Europe 20,196 — 20,196 Total Revenues $ 1,068,082 $ 780,317 $ 1,848,399 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 920,579 $ — $ 920,579 Ecoproducts 132,389 — 132,389 Environmental systems for aluminum dross and scrap processing 15,114 — 15,114 Waste processing and reuse solutions — 780,317 780,317 Total Revenues $ 1,068,082 $ 780,317 $ 1,848,399 Twelve Months Ended December 31, 2020 (In thousands) Harsco Environmental Segment Harsco Consolidated Totals Primary Geographical Markets (a)(b) : North America $ 249,904 $ 619,588 $ 869,492 Western Europe 377,066 — 377,066 Latin America (c) 119,457 — 119,457 Asia-Pacific 87,608 — 87,608 Middle East and Africa 63,427 — 63,427 Eastern Europe 16,983 — 16,983 Total Revenues $ 914,445 $ 619,588 $ 1,534,033 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 781,060 $ — $ 781,060 Ecoproducts 120,432 — 120,432 Environmental systems for aluminum dross and scrap processing 12,953 — 12,953 Waste processing and reuse solutions — 619,588 619,588 Total Revenues $ 914,445 $ 619,588 $ 1,534,033 Twelve Months Ended December 31, 2019 (In thousands) Harsco Environmental Segment Harsco Consolidated Totals Primary Geographical Markets (b) : North America $ 294,367 $ 169,522 $ 463,889 Western Europe 386,593 — 386,593 Latin America (c) 146,040 — 146,040 Asia-Pacific 128,949 — 128,949 Middle East and Africa 60,402 — 60,402 Eastern Europe 18,496 — 18,496 Total Revenues $ 1,034,847 $ 169,522 $ 1,204,369 Key Product and Service Groups: Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 888,851 $ — $ 888,851 Ecoproducts 127,874 — 127,874 Environmental systems for aluminum dross and scrap processing 18,122 — 18,122 Waste processing and reuse solutions — 169,522 169,522 Total Revenues $ 1,034,847 $ 169,522 $ 1,204,369 (a) The Company acquired ESOL in 2020 and Clean Earth in 2019. The results of both are included in the Harsco Clean Earth Segment. The operating results of the former Harsco Rail Segment and Harsco Industrial Segment have been reflected as discontinued operations in the Consolidated Statements of Operations. See Note 3, Acquisition 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 (advances on contracts), which are included in Other current liabilities and Other liabilities on the Consolidated Balance Sheets. The Company may recognize revenue in advance of being able to contractually invoice the customer (contract assets), which is included in Other current assets on the Consolidated Balance Sheets. Contract assets are transferred to Trade accounts receivable, net, when right to payment becomes unconditional. Contract assets and advances on contracts are reported as a net position, on a contract-by-contract basis, at the end of each reporting period. The Company had contract assets totaling $3.1 million at December 31, 2021 and $2.5 million at December 31, 2020. The increase is due principally to additional contract assets recognized in excess of the transfer of contract assets to accounts receivable. The Company had advances on contracts totaling $4.1 million at December 31, 2021 and $2.7 million at December 31, 2020. The increase is due principally to the receipts of new advances on contracts in excess of the recognition of revenue on previously received advances on contracts during the period. During the year ended December 31, 2021, the Company recognized approximately $15 million of revenue related to amounts previously included in advances on contracts.

Other Expenses

Other Expenses	12 Months Ended
	Dec. 31, 2021
Other Income and Expenses [Abstract]
Other Expenses	Other (Income) Expenses, Net The major components of this Consolidated Statements of Operations caption are as follows: (In thousands) 2021 2020 2019 Net gains Harsco Environmental Segment $ (8,902) $ (3,723) $ (6,303) Employee termination benefit costs Harsco Environmental Segment 2,852 9,389 1,254 Clean Earth Segment 433 833 1,960 Corporate 1,481 27 1,012 Total employee termination benefit costs 4,766 10,249 4,226 Other costs to exit activities Harsco Environmental Segment 640 504 970 Clean Earth Segment 23 — — Corporate — 29 196 Total other costs to exit activities 663 533 1,166 Impaired asset write-downs Harsco Environmental Segment 942 776 632 Clean Earth Segment 63 — — Total impaired asset write-downs 1,005 776 632 Contingent consideration adjustments Harsco Environmental Segment — — (8,506) Harsco Clean Earth Segment — 112 825 Corporate — 2,274 — Total contingent consideration adjustments — 2,386 (7,681) Other income (1,254) (149) (234) Total other (income) expenses, net $ (3,722) $ 10,072 $ (8,194) Net Gains Net gains result from the sales of redundant properties (primarily land, buildings and related equipment) and non-core assets. In 2021, gains related to assets sold principally in Western Europe. In 2020, gains related to assets sold principally in Latin America and Western Europe. In 2019, gains related to assets sold principally in Asia Pacific and North America; as well as a cumulative translation adjustment resulting from the substantial liquidation of a subsidiary in Western Europe. Employee Termination Benefit Costs Costs and the related liabilities associated with involuntary termination benefit costs for one-time benefit arrangements provided as part of an exit or disposal activity are recognized when a formal plan for reorganization is approved at the appropriate level of management and is communicated to the affected employees. Additionally, costs associated with ongoing benefit arrangements, or in certain countries where statutory requirements dictate a minimum required benefit, are recognized when they are probable and estimable. The employee termination benefit costs in 2021 principally related to the Harsco Environmental Segment primarily in Western Europe and Asia Pacific; and the Harsco Corporate segment primarily in North America. The employee termination benefits costs in 2020 principally related to the Harsco Environmental Segment primarily in Western Europe, North America, Latin America and Asia Pacific. The employee termination benefits costs in 2019 principally related to the Harsco Clean Earth Segment primarily in North America; and the Harsco Environmental Segment primarily in Asia Pacific and Western Europe. Other Costs to Exit Activities Costs associated with exit or disposal activities include costs to terminate a contract and other costs associated with exit or disposal activities. Costs to terminate a contract are recognized when an entity terminates the contract or when an entity ceases using the right conveyed by the contract. This includes the costs to terminate the contract before the end of its term or the costs that will continue to be incurred under the contract for its remaining term without economic benefit to the entity. Other costs associated with exit or disposal activities (e.g., costs to consolidate or close facilities and relocate equipment or employees) are recognized and measured at their fair value in the period in which the liability is incurred. In 2021, exit costs were incurred principally in the Harsco Environmental Segment, mostly in North America. In 2020 and 2019, exit costs were incurred in the Harsco Environmental Segment across several regions. Impaired Asset Write-downs Impaired asset write-downs are measured as the amount by which the carrying amount of assets exceeds their fair value. Fair value is estimated based upon the expected future realizable cash flows including anticipated selling prices. Non-cash impaired asset write-downs are included in, Other, net, on the Consolidated Statements of Cash Flows as adjustments to reconcile net income (loss) to net cash provided by operating activities. In all years presented, impaired asset write-downs were incurred primarily in the Harsco Environmental Segment across several regions. Contingent Consideration Adjustments The Company acquired Clean Earth in 2019. Included in liabilities acquired was a contingent liability resulting from a prior Clean Earth acquisition. In 2018, the Company acquired Altek, which is included in the Harsco Environmental Segment, and the purchase price included contingent consideration based on the performance of Altek through 2021. Each quarter until settlement of the related contingencies, the Company assesses the likelihood that the acquired businesses will achieve performance goals and the resulting fair value of the contingent consideration and any future adjustments (increases or decreases) are included in operating results. The Company's acquisition of Clean Earth included an agreement to reimburse the sellers for any usage of assumed net operating losses in a post-closing period for up to five years. In 2020, Corporate recorded an adjustment related to the expected reimbursement of these net operating losses. Other Income Other income in 2021 relates principally to compensation received for a site previously exited in the Harsco Environmental Segment.

Components of Accumulated Other

Components of Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Components of Accumulated Other Comprehensive Loss	Components of Accumulated Other Comprehensive Loss AOCI is included on the Consolidated Statements of Stockholders' Equity. The components of AOCI, net of the effect of income taxes, and activity for the years ended December 31, 2021 and 2020 are 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 Loss on Marketable Securities Total Balance at December 31, 2019 (143,340) (3,717) (440,562) (3) (587,622) OCI before reclassifications 7,854 (a) (3,709) (b) (96,684) (c) (6) (92,545) Amounts reclassified from AOCI, net of tax 12,906 1,586 22,746 — 37,238 Total OCI 20,760 (2,123) (73,938) (6) (55,307) Less: OCI attributable to noncontrolling interests (2,812) — — — (2,812) OCI attributable to Harsco Corporation 17,948 (2,123) (73,938) (6) (58,119) Balance at December 31, 2020 $ (125,392) $ (5,840) $ (514,500) $ (9) $ (645,741) 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 Loss on Marketable Securities Total Balance at December 31, 2020 $ (125,392) $ (5,840) $ (514,500) $ (9) $ (645,741) OCI before reclassifications (10,994) (a) 441 (b) 69,517 (c) 31 58,995 Amounts reclassified from AOCI, net of tax 2,375 22,735 25,110 Total OCI (10,994) 2,816 92,252 31 84,105 Plus: OCI attributable to noncontrolling interests 1,497 — — 1,497 OCI attributable to Harsco Corporation (9,497) 2,816 92,252 31 85,602 Balance at December 31, 2021 $ (134,889) $ (3,024) $ (422,248) $ 22 $ (560,139) (a) Principally foreign currency fluctuation. (b) Principally net change from periodic revaluations. (c) Principally changes due to annual actuarial remeasurements and foreign currency translation. Amounts reclassified from AOCI for 2021 and 2020 are as follows: Year Ended December 31 2021 Year Ended December 31 2020 Affected Caption on the (In thousands) Amortization of defined benefit pension items (d) : Actuarial losses $ 23,657 $ 19,623 Defined benefit pension income (expense) Prior-service costs 582 511 Defined benefit pension income (expense) Pension asset transfer - discontinued businesses — 5,363 Gain on sale of discontinued businesses Settlement/curtailment losses (72) (110) Discontinued operations Settlement/curtailment losses — 18 Defined benefit pension income (expense) Total before tax 24,167 25,405 Tax benefit (1,432) (2,659) Total reclassification of defined benefit pension items, net of tax $ 22,735 $ 22,746 Recognition of cumulative foreign currency translation adjustments: Gain on substantial liquidation of subsidiaries (e) $ — $ 12,906 Other (income) expenses, net Amortization of cash flow hedging instruments: Foreign currency exchange forward contracts $ (129) $ (1,026) Discontinued operations CCIRs — 1,015 Interest expense Interest rate swaps 3,474 2,589 Interest expense Total before tax 3,345 2,578 Tax benefit (970) (992) Total reclassification of cash flow hedging instruments $ 2,375 $ 1,586 (d) These AOCI components are included in the computation of NPPC. See Note 10, Employee Benefit Plans, for additional information. (e) No tax impact.

Interim Reporting

Interim Reporting	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Two-Year Summary of Quarterly Results (Unaudited)	Two-Year Summary of Quarterly Results (Unaudited) (In millions, except per share amounts) 2021 (a) Quarterly First Second Third Fourth Revenues $ 447.3 $ 468.7 $ 470.4 $ 462.1 Gross profit (b) 89.9 93.2 95.0 79.7 Net income (loss) attributable to Harsco Corporation 0.1 13.4 7.6 (24.4) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.02) $ 0.11 $ 0.06 $ 0.13 Discontinued operations (c) 0.02 0.06 0.03 (0.43) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ 0.17 $ 0.10 (d) $ (0.31) (d) Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.02) $ 0.11 $ 0.06 $ 0.13 Discontinued operations (c) 0.02 0.06 0.03 (0.43) Diluted loss per share attributable to Harsco Corporation common stockholders $ — $ 0.17 $ 0.09 $ (0.30) 2020 (a) Quarterly First Second Third Fourth Revenues $ 320.4 $ 365.6 $ 416.6 $ 431.5 Gross profit (b) 62.3 62.1 80.5 86.8 Net income (loss) attributable to Harsco Corporation 0.1 (10.6) (9.6) (6.3) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.17) $ (0.25) $ (0.12) $ (0.09) Discontinued operations (c) 0.17 0.12 — 0.01 Basic earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ (0.13) $ (0.12) $ (0.08) Diluted income per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.17) $ (0.25) $ (0.12) $ (0.09) Discontinued operations (c) 0.17 0.12 — 0.01 Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ (0.13) $ (0.12) $ (0.08) (a) Sum of the quarters may not equal the total year due to rounding. (b) Gross profit is defined as Revenues less costs and expenses associated directly with or allocated to products sold or services rendered. (c) Discontinued operations related principally to the Company's former Harsco Rail Segment. (d) Does not total due to rounding.

SCHEDULE II. VALUATION AND QUAL

SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS	SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS Continuing Operations (In thousands) COLUMN A COLUMN B COLUMN C COLUMN D COLUMN E Additions (Deductions) Additions (Deductions) Description Balance at Charged to Due to Other Balance at End For the year 2021: Allowance for Expected Credit Losses and Doubtful Accounts $ 7,488 $ 589 $ (206) $ (609) (a) $ 7,262 Deferred Tax Assets—Valuation Allowance 108,563 (4,252) (3,502) (8,424) (b) 92,385 For the year 2020: Allowance for Expected Credit Losses and Doubtful Accounts $ 13,265 $ 1,961 $ (104) $ (7,634) (a) $ 7,488 Deferred Tax Assets—Valuation Allowance 100,245 6,936 1,305 77 (b) 108,563 For the year 2019: Allowance for Doubtful Accounts $ 4,396 $ 7,123 $ 370 $ 1,376 (a) $ 13,265 Deferred Tax Assets—Valuation Allowance 112,706 (8,545) 860 (4,776) (b) 100,245 (a) Includes the write-off of previously reserved accounts receivable balances. Also, 2020 includes the acquisition of ESOL and 2019 includes the acquisition of Clean Earth. 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. (b) Includes a decrease of $19.3 million related to pension adjustments recorded through AOCI, and an increase of $14.4 million related to the UK tax rate change in 2021. Includes a decrease of $15.5 million related to foreign tax credit carryforwards due to statutory limitation expiration in the U.S., an increase of $13.0 million related to pension adjustments recorded through AOCI and an increase of $3.7 million related to the UK tax rate change in 2020. Includes a decrease of $5.6 million related to the loss of certain tax attributes in certain foreign dormant entities due to merger and liquidation in 2019.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Amendment to Senior Secured Credit Facilities On February 22, 2022, the Company entered into Amendment No. 9 (“Amendment No. 9 to the Third Amended and Restated Credit Agreement"), dated as of November 2, 2016 (as the same has been amended, supplemented or otherwise modified prior to February 22, 2022, and as further amended by Amendment No. 9, the “Senior Secured Credit Facility”), with Bank of America, N.A., as administrative agent and as collateral agent, the lenders party thereto, and the other parties thereto. Amendment No. 9 reset the required level of the net debt to consolidated adjusted EBITDA ratio covenant beginning with the quarter ending on March 31, 2022 through the quarter ending December 31, 2023. As a result of this amendment, the net debt to consolidated adjusted EBITDA ratio covenant was set at 5.75 for the quarter ending March 31, 2022, and then decreases quarterly by 0.25 until reaching 4.00 for the quarters ending December 31, 2023 and thereafter. In addition, upon closing on the

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Consolidation	ConsolidationThe consolidated financial statements include all accounts of Harsco Corporation (the "Company"), all entities in which the Company has a controlling voting interest and variable interest entities required to be consolidated in accordance with U.S. GAAP. Intercompany accounts and transactions have been eliminated among consolidated entities.
Reclassifications	Reclassifications Certain reclassifications have been made to prior year amounts to conform with current year classifications.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash on hand, demand deposits and short-term investments that are highly liquid in nature and have an original maturity of three months or less.
Restricted Cash	Restricted Cash The Company had restricted cash of $4.2 million and $3.2 million at December 31, 2021 and 2020, respectively, and the restrictions are primarily related to collateral provided for certain guarantees of the Company’s performance.
Inventories	Inventories Inventories are accounted for using the average cost, first-in, first-out ("FIFO"), or last-in, first-out ("LIFO") method. Inventory accounted for under the average cost and FIFO methods are stated at the lower of cost or net realizable value. Inventory accounted for under the LIFO method is stated at the lower of cost or market. See Note 5, Inventories, for additional information.
Depreciation	Depreciation Property, plant and equipment is recorded at cost and depreciated over the estimated useful lives of the assets using, principally, the straight-line method. When property, plant and equipment is retired from service, the cost of the retirement is charged to the allowance for depreciation to the extent of the accumulated depreciation and the balance is charged to income. Long-lived assets to be disposed of by sale are not depreciated while they are classified as held-for-sale.
Leases	Leases The Company leases certain property and equipment under noncancelable lease agreements. The Company determines if a contract or arrangement contains a lease at inception. All leases are evaluated and classified as either an operating or finance lease. A lease is classified as a finance lease if any of the following criteria are met: (i) ownership of the underlying asset transfers to the Company by the end of the lease term; (ii) the lease contains an option to purchase the underlying asset that the Company is reasonably expected to exercise; (iii) the lease term is for a major part of the remaining economic life of the underlying asset; (iv) the present value of the sum of lease payments and any residual value guaranteed by the Company equals or exceeds substantially all of the fair value of the underlying asset; or (v) the underlying asset is of a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. A lease that does not meet any of the criteria to be classified as a finance lease is classified as an operating lease. Operating leases are included as Right-of-use assets, net, Current portion of operating lease liabilities, and Operating lease liabilities on the Consolidated Balance Sheets. ROU assets and operating lease liabilities are recognized based on the present value of the future lease payments over the lease term at the commencement date. As most of the Company’s leases do not provide an implicit rate for use in determining the present value of future payments, the Company uses an incremental borrowing rate. This incremental borrowing rate reflects the creditworthiness of the Company for a lending period commensurate to the term of the lease and the standard lending practices related to such loans in the respective jurisdiction where the underlying assets are located. ROU assets also include any lease payments made and exclude any lease incentives and initial direct costs incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term, including rent abatement periods and rent holidays. Certain of the Company's leases are subject to annual changes in an index or are subject to adjustments for which the amounts are not readily determinable at lease inception. While lease liabilities are not remeasured as a result of changes to these costs, changes are treated as variable lease payments and recognized in the period in which the obligation for those payments was incurred. Finance leases are included as Property, plant and equipment, net; Current maturities of long-term debt and Long-term debt on the Consolidated Balance Sheets. Finance lease costs are split between depreciation expense related to the asset and interest expense on the lease liability, using the effective rate charged by the lessor.
Goodwill and Other Intangible Assets	Business Combinations and Goodwill The Company accounts for business combinations using the acquisition method of accounting, which requires that once control is obtained, all assets acquired and liabilities assumed, including amounts attributable to noncontrolling interests, be recorded at their respective fair values at the date of acquisition. The excess of purchase price over the fair values of identifiable assets and liabilities is recorded as goodwill. The determination of fair value of assets acquired and liabilities assumed requires numerous estimates and assumptions with respect to the timing and amounts of cash flow projections, revenue growth rates, customer attrition rates, discount rates and useful lives. Such estimates are based upon assumptions believed to be reasonable, and, when appropriate, include assistance from independent third-party valuation firms. During the measurement period, which is up to one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with corresponding offsets to goodwill. In accordance with U.S. GAAP, goodwill is not amortized and is tested for impairment at least annually or more frequently if indicators of impairment exist or if a decision is made to dispose of a business. Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment for which discrete financial information is available. A significant amount of judgment is involved in determining if an indicator of impairment has occurred. Such indicators may include declining cash flows or operating losses at the reporting unit level, a significant adverse change in legal factors or in the business climate, an adverse action or assessment by a regulator, unanticipated competition, a loss of key personnel or a more likely than not expectation that a reporting unit or a significant portion of a reporting unit will be sold or otherwise disposed of, among others. In applying the goodwill impairment test, the Company has the option to perform a qualitative test or a quantitative test . Under the qualitative test, the Company assesses qualitative factors to determine whether it is more likely than not that the fair value of the reporting units is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting unit and other entity and reporting unit specific events. If after assessing these qualitative factors, the Company determines it is “more-likely-than-not” that the fair value of the reporting unit is less than the carrying value, the Company would perform a quantitative test. The quantitative approach of testing for goodwill impairment involves comparing the current fair value of each reporting unit to the carrying value, including goodwill. The Company uses a discounted cash flow model (“DCF model”) to estimate the current fair value of reporting units, as management believes forecasted operating cash flows are the best indicator of current fair value. A number of significant assumptions and estimates are involved in the preparation of DCF models including future revenues and operating margin growth, the weighted-average cost of capital (“WACC”), tax rates, capital spending, pension funding, the impact of business initiatives and working capital projections. These assumptions and estimates may vary significantly among reporting units. DCF models are based on approved long-range plans for the early years and historical relationships and projections for later years. WACC rates are derived from internal and external factors including, but not
Impairment of Long-Lived Assets (Other than Goodwill)	Long-Lived Assets Impairments (Other than Goodwill)Long-lived assets or asset groups are reviewed for impairment when events and circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Long-lived assets or asset groups are reviewed for impairment when events and circumstances indicate the book value of an asset or asset group may be impaired. The Company's policy is to determine if an impairment loss exists when it is determined that the carrying amount of the asset or asset group exceeds the sum of the expected undiscounted future cash flows resulting from use of the asset or asset group and its eventual disposition. Impairment losses are measured as the amount by which the carrying amount of the asset or asset group exceeds its fair value, normally as determined in either open market transactions or through the use of a DCF model. Long-lived assets or asset groups to be disposed of are reported at the lower of the carrying amount or fair value less cost to sell.
Deferred Financing Costs	Deferred Financing Costs The Company has incurred debt issuance costs which are recognized as a reduction of Long-term debt on the Consolidated Balance Sheets. Debt issuance costs are amortized and recognized as interest expense over the contractual term of the related indebtedness or shorter period if appropriate based upon contractual terms. Whenever indebtedness is modified from its original terms, an evaluation is made whether an accounting modification or extinguishment has occurred in order to determine the accounting treatment for debt issuance costs related to the debt modification.
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 Segment. Product revenues include portions of the Harsco Environmental Segment. Harsco Environmental - This Segment provides on-site services, under long-term contracts, for material logistics; product quality improvement and resource recovery from iron, steel and metals manufacturing; manufactures and sells industrial abrasives and roofing granule products; and manufactures aluminum dross and scrap processing systems. • Service revenues are recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an output method based on work performed (liquid steel tons processed, weight of material handled, etc.) to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms, which may include both fixed and variable portions. The fixed portion is recognized as earned (normally monthly) over the contractual period. The variable portion is recognized as services are performed and differs based on the volume of services performed. Given the long-term nature of these arrangements, most contracts permit periodic adjustment of either the variable or both the fixed and variable portions based on the changes in macroeconomic indicators, including changes in commodity prices. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis as services are performed. • Product revenues are recognized at the point when control transfers to the customer. Control generally transfers at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. Transaction prices are based on contractual terms, which are generally fixed and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. Amounts are billed and payable upon completion of each transaction. • Product revenues in the aluminum dross and scrap process systems business are generally recognized over time as control is transferred to the customer. Control transfers over time because aluminum dross and scrap systems are customized, have no alternate use and the Company has an enforceable right to payment. The Company utilizes an input method based on costs incurred ("cost-to-cost method") to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. The Company may receive periodic payments associated with key milestones with any remaining consideration billed and payable upon completion of the transaction. Harsco Clean Earth - This Segment provides specialty waste processing and beneficial reuse solutions for hazardous wastes, and soil and dredged materials. • Revenues are recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an output method based on the amount of materials received for processing to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contractual terms which are principally variable based on volume and recognized as services are performed. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis. Harsco Rail - This business sells railway track maintenance equipment, after-market parts, Protran/safety equipment and provides railway track maintenance services. • For standard railway track maintenance equipment sales, revenue is recognized at the point when control transfers to the customer. Control generally transfers at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. In certain railway track maintenance equipment sales, revenue is recognized over time because such equipment is highly customized, has no alternate use and the Company has an enforceable right to payment. The former Harsco Rail Segment uses the cost-to-cost method to measure progress because it is the measure that best depicts the transfer of control to the customer, which occurs as the former Harsco Rail Segment incurs costs under the contracts. Under the cost-to-cost method, the extent of progress towards completion is based on the ratio of costs incurred to total estimated costs at completion which includes both actual costs already incurred and the estimated costs to complete. Accounting for contracts with customers using the cost-to-cost method requires significant judgment relative to assessing risks, estimating contract revenues (including estimates of variable consideration, if applicable, as well as estimating any liquidating damages or penalties related to performance), estimating contract costs (including estimating engineering costs to design the machine and the material, labor and overhead manufacturing costs to build the machine); making assumptions for schedule and technical items; properly executing the engineering and design phases consistent with customer expectations; the availability and costs of labor and material resources; productivity; and evaluating whether a significant financing component is present. Due to the number of years it may take to complete certain contracts and the scope and nature of the work required to be performed on those contracts, estimating total revenues and costs at completion is inherently complicated and subject to many variables. Transaction prices are based on contracted terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing either the adjusted market assessment or expected cost plus a margin approach. For certain transactions, the Company receives periodic payments associated with key milestones. In limited instances, those payments are intended to provide financing with such transactions being treated as including a significant financing component. Any remaining consideration is billed and payable upon completion of the transaction. Railway track maintenance equipment revenue of approximately $102 million was recognized using the cost-to-cost method in 2021, the net profit or loss of which is included in Income (loss) from discontinued businesses in the Consolidated Statements of Operations. • For after-market parts sales and Protran/safety equipment, revenue is recognized at the point when control transfers to the customer. Control generally transfers to the customer at the point of shipment for domestic orders and in accordance with the international commercial terms included in contracts for export sales. Transaction prices are based on contracted terms, which are generally fixed, and when the standalone selling price is not directly observable, allocated to performance obligations utilizing an adjusted market assessment approach. Amounts are billed and payable upon completion of each contract. • For railway track maintenance services, revenue is recognized over time as the customer simultaneously receives the benefits provided by the Company's performance. The Company utilizes an appropriate output method based on work performed (feet, miles, shifts worked, etc.) to measure progress, which is deemed to best depict the transfer of value to the customer and revenue earned by the Company. Transaction prices are based on contracted terms, which are generally variable. The variable portion is recognized as services are performed and differs based on the value of services. Given the long-term nature of these arrangements, most contracts permit periodic adjustment based on the changes in macroeconomic indicators. Transaction prices, when the standalone selling price is not directly observable, are allocated to performance obligations utilizing an expected cost plus a margin approach. Amounts are typically billed and payable on a monthly basis as services are performed. The Company has elected to utilize the following practical expedients on an ongoing basis: • The Company has not adjusted the promised amount of consideration for the effects of a significant financing component if the Company expects, at contract inception, that the period between when the Company transfers the promised good or services to the customer and when the customer pays for that good or service would be one year or less; and • The Company has elected to exclude disclosures related to unsatisfied performance obligations where the related contract has a duration of one year or less; or where the consideration is entirely variable. Accordingly, the Company's disclosure related to unsatisfied performance obligations is limited to the fixed portion of fees related to metals services in the Harsco Environmental Segment. Taxes assessed by governmental authorities that are both imposed on and concurrent with a specific revenue-producing transaction, that are collected by the Company from a customer, are excluded from revenue. Additionally, in certain contracts, the Company facilitates shipping and handling activities after control has transferred to the customer. The Company has elected to record all shipping and handling activities as costs to fulfill a contract. In situations where the shipping and handling costs have not been incurred at the time revenue is recognized, the respective shipping and handling costs are accrued.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of the events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the consolidated financial statements and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company records deferred tax assets to the extent that the Company believes that these assets will more likely than not be realized. In making such determinations, the Company considers all available positive and negative evidence, including future reversals of existing deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial results. If the Company determines that it will not be able to realize deferred income tax assets in the future, a valuation allowance is recorded. If sufficient positive evidence arises in the future indicating that all or a portion of the deferred tax assets meet the more likely than not standard for realization, the valuation allowance would be reduced accordingly in the period that such a conclusion is reached. The Company prepares and files tax returns based on interpretation of tax laws and regulations and records its provision for income taxes based on these interpretations. Uncertainties may exist in estimating the Company's tax provisions and in filing tax returns in the many jurisdictions in which the Company operates, and as a result these interpretations may give rise to an uncertain tax position. The tax benefit from an uncertain tax position is recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on its technical merits. Each subsequent period the Company determines if existing or new uncertain tax positions meet a more likely than not recognition threshold and adjusts accordingly. The Company recognizes interest and penalties related to unrecognized tax benefits within Income tax expense in the accompanying Consolidated Statements of Operations. Liabilities for uncertain tax positions are included in Other liabilities on the Consolidated Balance Sheets. The significant assumptions and estimates described in the preceding paragraphs are important contributors to the effective tax rate each year.
Accrued Insurance and Loss Reserves	Accrued Insurance and Loss Reserves The Company retains a significant portion of the risk for certain U.S. workers' compensation, U.K. employers' liability, automobile, general and product liability losses. During 2021, 2020 and 2019, the Company recorded insurance expense from continuing operations related to these lines of coverage of $25.6 million, $21.1 million and $12.5 million, respectively. Reserves have been recorded that reflect the undiscounted estimated liabilities including claims incurred but not reported. When a recognized liability is covered by third-party insurance, the Company records an insurance claim receivable to reflect the covered liability. Changes in the estimates of the reserves are included in net income(loss) in the period determined. During 2021, 2020 and 2019, the Company recorded insurance reserve adjustments that decreased pre-tax insurance expense
Foreign Currency Translation	Foreign Currency TranslationThe financial statements of the Company's subsidiaries outside the U.S., except for those subsidiaries located in highly inflationary economies and those entities for which the U.S. dollar is the currency of the primary economic environment in which the entity operates, are measured using the local currency as the functional currency. Assets and liabilities of these subsidiaries are translated at the exchange rates at the balance sheet date. Resulting translation adjustments are recorded in the cumulative translation adjustment account, a separate component of AOCI on the Consolidated Balance Sheets. Income and expense items are translated at average monthly exchange rates. Gains and losses from foreign currency transactions are included in Operating income from continuing operations. For subsidiaries operating in highly inflationary economies, and those entities for which the U.S. dollar is the currency of the primary economic environment in which the entity operates, gains and losses on foreign currency transactions and balance sheet translation adjustments are included in Operating income from continuing operations.
Financial Instruments and Hedging	Financial Instruments and Hedging The Company has operations throughout the world that are exposed to fluctuations in related foreign currencies in the normal course of business. The Company seeks to reduce exposure to foreign currency fluctuations through the use of forward exchange contracts. The Company does not hold or issue financial instruments for trading purposes and it is the Company's policy to prohibit the use of derivatives for speculative purposes. The Company has a Foreign Currency Risk Management Committee that meets periodically to monitor foreign currency risks. The Company executes foreign currency exchange forward contracts to hedge transactions for firm purchase commitments, to hedge variable cash flows of forecasted transactions and for export sales denominated in foreign currencies. These contracts are generally for 90 days or less; however, where appropriate, longer-term contracts may be utilized. For those contracts that are designated as qualified cash flow hedges, gains or losses are recorded in AOCI on the Consolidated Balance Sheets. The Company uses interest rate swaps in conjunction with certain debt issuances in order to secure a fixed interest rate. The interest rate swaps are recorded on the Consolidated Balance Sheets at fair value, with changes in value attributed to the effect of the swaps’ interest spread and changes in the credit worthiness of the counter-parties recorded in AOCI. Amounts recorded in AOCI on the Consolidated Balance Sheets are reclassified into income in the same period or periods during which the hedged forecasted transaction affects income. The cash flows from these contracts are classified consistent with the cash flows from the transaction being hedged (e.g., the cash flows related to contracts to hedge the purchase of fixed assets are included in cash flows from investing activities, etc.). The Company also enters into certain forward exchange contracts that are not designated as hedges. Gains and losses on these contracts are recognized in operations based on changes in fair market value. For fair value hedges of a firm commitment, the gain or loss on the derivative and the offsetting gain or loss on the hedged firm commitment are recognized currently in operations.
Earnings Per Share	Earnings Per ShareBasic earnings per share are calculated using the weighted-average shares of common stock outstanding, while diluted earnings per share reflect the dilutive effects of stock-based compensation. Dilutive securities are not included in the computation of loss per share when the Company reports a net loss from continuing operations as the impact would be anti-dilutive. All share and per share amounts are restated for any stock splits and stock dividends that occur prior to the issuance of the financial statements.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses. Actual results could differ from those estimates. Impact of COVID-19 Beginning in early 2020, overall global economic conditions were significantly impacted by COVID-19. The Company operated, since the onset of the pandemic, as a provider of certain essential services in the U.S. and other countries and overall business conditions have strengthened since the second quarter of 2020. 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 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 year ended December 31, 2021 related to COVID-19. 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.
Recently Adopted and Recently Issued Accounting Standards	Recently Adopted and Recently Issued Accounting Standards The following accounting standards have been adopted in 2021: On January 1, 2021 the Company adopted changes issued by the FASB 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. These changes did not have a material impact on the Company's consolidated financial statements. The following accounting standards have been issued and become effective for the Company at a future date: 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. In January 2021, the FASB issued additional clarification changes. 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 the Company's 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. The changes become effective January 1, 2022. Management has concluded that this standard will not have an impact on the Company's consolidated financial statements. In November 2021, the FASB issued changes that improve the transparency of government assistance received by entities. The changes require disclosure of the nature of transactions, including significant terms and conditions, accounting policies used, and financial statement line items affected by the transactions. The changes become effective January 1, 2022. Other than required expanded disclosures, the adoption of these changes will not have a material impact on the Company's consolidated financial statements.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Summary of assets acquired and liabilities assumed	The fair value recorded for the assets acquired and liabilities assumed for ESOL is as follows: (In millions) April 6 Measurement Period Adjustments Final Valuation Cash and cash equivalents $ 0.4 $ — $ 0.4 Trade accounts receivable 124.1 (1.5) 122.6 Inventory 5.0 — 5.0 Other current assets 0.7 (0.7) — Property, plant and equipment 105.3 (3.9) 101.4 Right-of-use assets, net 56.0 — 56.0 Goodwill 152.0 1.3 153.3 Intangible assets 161.0 — 161.0 Other assets 0.2 — 0.2 Accounts payable (48.6) (1.5) (50.1) Accrued expenses (17.5) (1.8) (19.3) Current portion of operating lease liabilities (16.6) — (16.6) Other current liabilities (6.4) (0.2) (6.6) Environmental liabilities (24.4) — (24.4) Deferred income taxes (15.5) (1.5) (17.0) 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: (In millions) June 28 Measurement Period Adjustments Final Valuation Cash and cash equivalents $ 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, net 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 (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
Summary of intangible assets and amortization periods	The following table details the valuation of identifiable intangible assets and amortization periods for ESOL and the non-compete agreement: (Dollars in millions) Weighted-Average Amortization Period April 6 Measurement Period Adjustments Final Valuation 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: (Dollars in millions) Weighted-Average Amortization Period June 28 Measurement Period Adjustments Final Valuation Permits 18 years $ 176.1 $ (6.0) $ 170.1 Customer relationships and backlog 8 years 33.4 (12.9) 20.5 Air rights Usage based (b) 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 (b) The Company estimates that based on current usage that the expected useful life would be 27 years.
Disposal Groups, Including Discontinued Operations	The former Harsco Rail Segment's balance sheet positions as of December 31, 2021 and 2020 are presented as Assets held-for-sale and Liabilities of assets held-for-sale in the Consolidated Balance Sheets and are summarized as follows: (in thousands) December 31 December 31 Trade accounts receivable, net $ 33,689 $ 52,077 Other receivables 4,740 3,045 Inventories 103,560 112,013 Current portion of contract assets 94,597 52,240 Other current assets 25,442 27,703 Property, plant and equipment, net 39,524 37,855 Right-of-use assets, net 3,108 4,354 Goodwill 13,026 13,026 Intangible assets, net 3,081 3,449 Deferred income tax assets 6,064 4,906 Other assets 6,432 6,316 Total Rail assets included in Assets held-for-sale $ 333,263 $ 316,984 Accounts payable $ 46,076 $ 53,937 Accrued compensation 2,171 1,503 Current portion of operating lease liabilities 1,619 1,745 Current portion of advances on contracts 62,401 37,462 Other current liabilities 49,732 33,280 Advances on contracts — 44,731 Operating lease liabilities 1,775 2,734 Deferred tax liabilities 5,736 4,461 Other liabilities 982 925 Total Rail liabilities included in Liabilities of assets held-for-sale $ 170,492 $ 180,778 Years ended December 31 (In thousands) 2021 2020 2019 Amounts directly attributable to the former Harsco Rail Segment: Service revenues $ 32,425 $ 31,642 $ 30,254 Product revenues 266,221 298,189 269,119 Cost of services sold 17,272 23,480 21,883 Cost of products sold 251,897 235,040 192,310 Income (loss) from discontinued businesses (19,967) 23,096 25,406 Additional amounts allocated to the former Harsco Rail Segment: Selling, general and administrative expenses (a) $ 178 $ — $ — The following is selected financial information included on the Consolidated Statements of Cash Flows attributable to the former Harsco Rail Segment: Years Ended December 31 (In thousands) 2021 2020 2019 Non-cash operating items Depreciation and amortization $ 4,329 $ 5,450 $ 4,876 Cash flows from investing activities Purchases of property, plant and equipment 1,406 7,962 15,274 Years ended December 31 (In thousands) 2021 2020 2019 Amounts directly attributable to the former Harsco Industrial Segment: Total revenues $ — $ 10,203 $ 306,972 Cost of products sold — 8,082 224,811 Gain on sale from discontinued businesses — 18,281 569,135 Income (loss) from discontinued businesses (3,510) (1,578) 27,823 Additional amounts allocated to the former Harsco Industrial Segment: Selling, general and administrative expenses (c) $ 3,510 $ 2,695 $ 8,429 Interest expense (d) — — 11,237 Loss on early extinguishment of debt (e) — — 5,314 (c) The Company allocated directly attributable transaction costs to discontinued operations. In addition, this caption includes costs directly attributable to retained contingent liabilities of the former Harsco Industrial Segment. (d) The Company allocated interest expense, including a portion of the amount reclassified into income for the Company's interest rate swaps, amortization of deferred financing costs, and $2.7 million related to interest rate swap terminations which were directly attributed with the mandatory repayment of certain debt resulting from the AXC disposal. (e) The Company allocated the $5.3 million write-off of deferred financing costs to discontinued operations as it directly attributed to the mandatory repayment of certain debt resulting from the AXC disposal.

Accounts Receivable and Note _2

Accounts Receivable and Note Receivable (Tables)	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Schedule of accounts receivable	Accounts receivable consist of the following: (In thousands) December 31 December 31 Trade accounts receivable $ 385,143 $ 362,801 Less: Allowance for expected credit losses (7,262) (7,488) Trade accounts receivable, net $ 377,881 $ 355,313 Other receivables (a) $ 33,059 $ 31,208 (a) Other receivables include employee receivables, insurance receivable, tax claims and refunds and other miscellaneous receivables not included in Trade accounts receivable, net. (In thousands) December 31 December 31 Note receivable $ 31,025 $ 35,806
Schedule of provision for doubtful accounts related to trade accounts receivable	The provision for doubtful accounts related to trade accounts receivable was as follows: Years Ended December 31 (In thousands) 2021 2020 2019 Provision for expected credit losses and doubtful accounts related to trade accounts receivable $ 589 $ 1,961 $ 7,123 The provision for doubtful accounts in 2019 primarily included a provision in the Harsco Environmental Segment related to a customer in the U.K entering administration which was subsequently written off in 2020.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2021
Accounts Receivable and Inventories [Abstract]
Schedule of inventories	Inventories consist of the following: (In thousands) December 31 December 31 Finished goods $ 8,323 $ 7,749 Work-in-process 5,393 2,795 Raw materials and purchased parts 21,188 20,259 Stores and supplies 35,589 30,198 Total inventories $ 70,493 $ 61,001 Valued at lower of cost or market: LIFO basis $ 14,133 $ 14,690 FIFO basis 7,567 5,485 Average cost basis 48,793 40,826 Total inventories $ 70,493 $ 61,001

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	Property, plant and equipment consist of the following: (In thousands) Estimated December 31 December 31 Land — $ 73,067 $ 73,237 Land improvements 5-20 years 16,970 17,500 Buildings and improvements (a) 5-30 years 221,236 224,909 Machinery and equipment (b) 3-20 years 1,507,214 1,512,966 Uncompleted construction — 63,816 39,587 Gross property, plant and equipment 1,882,303 1,868,199 Less: Accumulated depreciation (1,228,390) (1,237,845) Property, plant and equipment, net $ 653,913 $ 630,354

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table reflects the changes in carrying amounts of goodwill by segment for the years ended December 31, 2021 and 2020: (In thousands) Harsco Environmental Harsco Consolidated Balance at December 31, 2019 $ 395,113 $ 330,230 $ 725,343 Changes to goodwill (a) 1,480 152,417 153,897 Foreign currency translation 9,808 — 9,808 Balance at December 31, 2020 406,401 482,647 889,048 Changes to goodwill — 1,232 1,232 Foreign currency translation (7,171) — (7,171) Balance at December 31, 2021 $ 399,230 $ 483,879 $ 883,109 (a) The changes to goodwill related to the acquisition of ESOL, and immaterial acquisitions in the Harsco Environmental segment. See Note 3, Acquisitions and Dispositions.
Schedule of Acquired Finite-Lived Intangible Assets by Major Class	The following table reflects these intangible assets by major category: December 31, 2021 December 31, 2020 (In thousands) Gross Carrying Accumulated Gross Carrying Accumulated Customer related $ 104,322 $ 54,057 $ 105,222 $ 46,267 Permits 309,069 34,822 308,705 18,955 Technology related 39,886 13,415 40,274 9,654 Trade names 30,738 6,842 30,779 4,272 Air rights 26,139 1,675 26,139 1,044 Patents 179 138 192 139 Non-compete agreement 2,500 1,094 2,500 469 Other 3,407 1,396 3,335 1,230 Total $ 516,240 $ 113,439 $ 517,146 $ 82,030
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table shows the estimated amortization expense for the next five fiscal years based on current intangible assets. (In thousands) 2022 2023 2024 2025 2026 Estimated amortization expense (b) $ 31,600 $ 31,600 $ 31,100 $ 30,900 $ 28,900 (b) These estimated amortization expense amounts do not reflect the potential effect of future foreign currency exchange rate fluctuations.

Debt and Credit Agreements (Tab

Debt and Credit Agreements (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Line of Credit Facilities	The following table shows the amount outstanding under the Revolving Credit Facility and available credit at December 31, 2021. December 31, 2021 (In thousands) Facility Outstanding Outstanding Letters of Credit Available Revolving Credit Facility $ 700,000 $ 362,000 $ 29,824 $ 308,176
Schedule of Long-term Debt Instruments	The Company's long-term debt consists of the following: (In thousands) December 31 December 31 Senior Secured Credit Facilities (a) : New Term Loan with an interest rate of 2.75% at December 31, 2021 $ 497,500 $ — Term Loan A with an interest rate of 3.50% at December 31, 2020 — 280,000 Term Loan B with an interest rate of 3.25% at December 31, 2020 — 218,188 Revolving Credit Facility with an average interest rate of 2.5% and 2.8% at December 31, 2021 and 2020, respectively 362,000 281,000 5.75% Senior Notes due July 31, 2027 500,000 500,000 Other financing payable (including capital leases) in varying amounts due principally through 2026 with a weighted-average interest rate of 4.7% and 5.0% at December 31, 2021 and 2020, respectively 28,389 21,344 Total debt obligations 1,387,889 1,300,532 Less: deferred financing costs (18,217) (15,767) Total debt obligations, net of deferred financing costs 1,369,672 1,284,765 Less: current maturities of long-term debt (10,226) (13,576) Long-term debt $ 1,359,446 $ 1,271,189 (a) The current portion of long-term debt related to the Senior Secured Credit Facilities was $5.0 million and $10.5 million with the remainder reflected as Long-term debt at December 31, 2021 and 2020, respectively.
Schedule of Maturities of Long-term Debt	The maturities of long-term debt for the four years following December 31, 2022 are as follows: (In thousands) 2023 $ 17,331 2024 9,351 2025 7,560 2026 368,558

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lease, Cost [Table Text Block]	The components of lease expense were as follows: (In thousands) 2021 2020 2019 Finance leases: Amortization expense $ 2,510 $ 1,523 $ 1,234 Interest on lease liabilities 495 184 50 Operating leases 32,544 28,537 13,754 Variable and short-term leases 47,780 40,953 22,201 Sublease income (53) (202) (198) Total lease expense from continuing operations $ 83,276 $ 70,995 $ 37,041 Supplemental cash flow information related to leases was as follows: (In thousands) 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash flows used by operating activities - Operating leases (a) $ 33,645 $ 28,057 $ 15,143 Cash flows used by financing activities - Finance leases 2,847 1,367 1,317 ROU assets obtained in exchange for lease obligations: Operating leases (b) $ 42,442 $ 69,044 $ 65,525 Finance leases 11,495 6,220 2,658 (a) Cash flows include cash paid for operating leases of discontinued operations. (b) Cash flows include ROU assets of approximately $56 million that were recorded upon the acquisition of ESOL in 2020. See Note 3, Acquisitions and Dispositions, for additional information. Supplemental balance sheet information related to leases was as follows: (In thousands) 2021 2020 Operating Leases (c): Operating lease ROU assets $ 101,576 $ 92,495 Current portion of operating lease liabilities 25,590 23,117 Operating lease liabilities 74,571 67,126 Finance Leases: Property, plant and equipment, net $ 17,185 $ 8,434 Current maturities of long-term debt 3,756 1,683 Long-term debt 13,736 6,867 (c) The 2021 operating lease ROU assets and operating lease liabilities include a $15 million adjustment to record certain leases for ESOL. These leases have been incorrectly treated as short term leases versus operating leases since ESOL's acquisition on April 6, 2020. Supplemental additional information related to leases was as follows: 2021 2020 Other information: Weighted average remaining lease term - Operating leases (in years) 7.14 8.22 Weighted average remaining lease term - Finance leases (in years) 5.88 8.20 Weighted average discount rate - Operating leases 5.9 % 6.1 % Weighted average discount rate - Finance leases 4.6 % 5.1 %
Schedule of Future Minimum Rental Payments for Operating Leases
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Maturities of lease liabilities were as follows: (In thousands) Operating Leases Finance Year Ending December 31: 2022 $ 30,347 $ 4,483 2023 24,959 4,311 2024 18,612 3,901 2025 12,923 2,834 2026 8,641 1,733 After 2026 31,890 3,078 Total lease payments 127,372 20,340 Less: Imputed interest (27,211) (2,848) Total lease liabilities $ 100,161 $ 17,492
Finance Lease, Liability, Maturity [Table Text Block]	Maturities of lease liabilities were as follows: (In thousands) Operating Leases Finance Year Ending December 31: 2022 $ 30,347 $ 4,483 2023 24,959 4,311 2024 18,612 3,901 2025 12,923 2,834 2026 8,641 1,733 After 2026 31,890 3,078 Total lease payments 127,372 20,340 Less: Imputed interest (27,211) (2,848) Total lease liabilities $ 100,161 $ 17,492

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Net Benefit Costs	NPPC from continuing operations for U.S. and international plans for 2021, 2020 and 2019 is as follows: U.S. Plans International Plans (In thousands) 2021 2020 2019 2021 2020 2019 Net Periodic Pension Cost (Income): Defined benefit pension plans: Service cost $ — $ — $ 39 $ 1,805 $ 1,642 $ 1,308 Interest cost 4,813 7,381 10,551 12,652 17,599 22,148 Expected return on plan assets (12,199) (11,368) (10,297) (45,018) (41,013) (37,218) Recognized prior service costs — — — 582 512 326 Recognized losses 5,538 5,100 5,585 18,119 14,723 14,345 Settlement/curtailment loss (gain) — — 129 (6) 18 19 Defined benefit pension plan cost (income) (1,848) 1,113 6,007 (11,866) (6,519) 928 Multiemployer pension plans 640 620 727 1,035 969 1,167 Defined contribution plans 5,660 4,769 2,523 4,196 3,994 5,349 Net periodic pension cost (income) $ 4,452 $ 6,502 $ 9,257 $ (6,635) $ (1,556) $ 7,444
Schedule of Net Funded Status	The change in the financial status of the defined benefit pension plans and amounts recognized on the Consolidated Balance Sheets at December 31, 2021 and 2020 are as follows: U.S. Plans International Plans (In thousands) 2021 2020 2021 2020 Change in benefit obligation: Benefit obligation at beginning of year $ 296,660 $ 294,693 $ 1,119,552 $ 984,665 Service cost — — 1,805 1,642 Interest cost 4,813 7,381 12,652 17,599 Plan participants' contributions — — 15 18 Amendments — — — 1,088 Actuarial (gain) loss (8,063) 25,212 (58,567) 129,410 Settlements/curtailments — — (269) (256) Benefits paid (16,403) (17,675) (39,831) (43,952) Effect of foreign currency — — (13,159) 29,379 Acquisitions/divestitures — (12,951) — (41) Benefit obligation at end of year $ 277,007 $ 296,660 $ 1,022,198 $ 1,119,552 Change in plan assets: Fair value of plan assets at beginning of year $ 226,125 $ 226,268 $ 957,177 $ 860,321 Actual return on plan assets 19,005 24,975 40,382 95,132 Employer contributions 4,219 3,528 25,077 21,955 Plan participants' contributions — — 15 18 Settlements/curtailments — — (269) (256) Benefits paid (16,402) (17,675) (39,220) (43,527) Effect of foreign currency — — (9,910) 23,534 Acquisitions/divestitures — (10,971) — — Fair value of plan assets at end of year $ 232,947 $ 226,125 $ 973,252 $ 957,177 Funded status at end of year $ (44,060) $ (70,535) $ (48,946) $ (162,375)
Schedule of Amounts Recognized in Balance Sheet	Amounts recognized on the Consolidated Balance Sheets for defined benefit pension plans consist of the following at December 31, 2021 and 2020: U.S. Plans International Plans December 31 December 31 (In thousands) 2021 2020 2021 2020 Noncurrent assets $ — $ — $ 2,046 $ — Current liabilities 1,999 1,970 967 907 Noncurrent liabilities 42,061 68,565 50,025 161,468 AOCI 114,874 135,281 410,114 487,682
Schedule of Net Periodic Benefit Cost Not yet Recognized	Amounts recognized in AOCI for defined benefit pension plans consist of the following at December 31, 2021 and 2020: U.S. Plans International Plans (In thousands) 2021 2020 2021 2020 Net actuarial loss $ 114,874 $ 135,281 $ 400,497 $ 477,238 Prior service cost — — 9,617 10,444 Total $ 114,874 $ 135,281 $ 410,114 $ 487,682
Schedule of Expected Benefit Payments	Expected benefit payments for defined benefit pension plans over the next ten years are as follows: (In millions) 2022 2023 2024 2025 2026 2026-2030 U.S. Plans $ 27.2 $ 16.7 $ 16.6 $ 16.5 $ 16.4 $ 78.7 International Plans 40.9 41.9 43.1 44.5 45.9 245.3
Schedule of Assumptions Used	The weighted-average actuarial assumptions used to determine the defined benefit pension plan NPPC for 2021, 2020 and 2019 were as follows: U.S. Plans International Plans Global Weighted-Average 2021 2020 2019 2021 2020 2019 2021 2020 2019 Discount rates 2.4 % 3.2 % 4.2 % 1.4 % 2.1 % 2.9 % 1.6 % 2.4 % 3.2 % Expected long-term rates of return on plan assets 6.8 % 7.0 % 7.3 % 4.7 % 5.2 % 5.5 % 5.1 % 5.6 % 5.9 % The weighted-average actuarial assumptions used to determine the defined benefit pension plan obligations at December 31, 2021 and 2020 were as follows: U.S. Plans International Plans Global Weighted-Average December 31 December 31 December 31 2021 2020 2021 2020 2021 2020 Discount rates 2.7 % 2.4 % 1.9 % 1.4 % 2.1 % 1.6 %
Schedule of Accumulated Benefit Obligations	The accumulated benefit obligation for all defined benefit pension plans at December 31, 2021 and 2020 was as follows: U.S. Plans International Plans December 31 December 31 (In millions) 2021 2020 2021 2020 Accumulated benefit obligation $ 277.0 $ 296.7 $ 1,016.1 $ 1,113.4
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for defined benefit pension plans with accumulated benefit obligations in excess of plan assets at December 31, 2021 and 2020 were as follows: U.S. Plans International Plans December 31 December 31 (In millions) 2021 2020 2021 2020 Projected benefit obligation $ 277.0 $ 296.7 $ 988.6 $ 1,115.7 Accumulated benefit obligation 277.0 296.7 984.7 1,109.8 Fair value of plan assets 232.9 226.1 939.3 953.5
U.S. Plans | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Allocation of Plan Assets	The asset allocations attributable to the Company's U.S. defined benefit pension plans at December 31, 2021 and 2020, and the long-term target allocation of plan assets, by asset category, are as follows: Target Long-Term Percentage of Plan Assets U.S. Plans Asset Category 2021 2020 Domestic equity securities 18%-28% 22.8 % 30.8 % International equity securities 17%-27% 22.5 % 26.5 % Fixed income securities 41%-51% 45.9 % 33.4 % Cash and cash equivalents Less than 5% — % 0.7 % Other (a) 4%-14% 8.8 % 8.6 % (a) Investments within this caption include diversified global asset allocation funds and credit collection funds. The fair values of the Company's U.S. defined benefit pension plans' assets at December 31, 2021 by asset class are as follows: (In thousands) Total Level 1 Investments Valued at Net Asset Value (c) Domestic equities: Common stocks $ 5,180 $ 5,180 $ — Mutual funds—equities 48,411 48,411 — International equities: Mutual funds—equities 50,783 50,783 — Fixed income investments: Mutual funds—bonds 105,114 105,114 — Other—mutual funds 9,371 9,371 — Cash and money market accounts 1,624 1,624 — Other—partnerships/joint ventures 12,464 — 12,464 Total $ 232,947 $ 220,483 $ 12,464 The fair values of the Company's U.S. defined benefit pension plans' assets at December 31, 2020 by asset class are as follows: (In thousands) Total Level 1 Investments Valued at Net Asset Value Domestic equities: Common stocks $ 5,934 $ 5,934 $ — Mutual funds—equities 63,651 63,651 — International equities: Mutual funds—equities 59,933 59,933 — Fixed income investments: Mutual funds—bonds 75,441 75,441 — Other—mutual funds 8,944 8,944 — Cash and money market accounts 1,691 1,691 — Other - partnerships/joint ventures 10,531 — 10,531 Total $ 226,125 $ 215,594 $ 10,531
International Plans | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of Allocation of Plan Assets	The asset allocations attributable to the Company's international defined benefit pension plans at December 31, 2021 and 2020 and the long-term target allocation of plan assets, by asset category, are as follows: International Plans Asset Category Target Long-Term Percentage of Plan Assets 2021 2020 Equity securities 26.5 % 27.9 % 32.0 % Fixed income securities 65.5 % 63.6 % 49.5 % Cash and cash equivalents — 0.7 % 0.2 % Other (b) 8.0 % 7.8 % 18.3 % (b) Investments within this caption include diversified growth funds and real estate funds. The fair values of the Company's international defined benefit pension plans' assets at December 31, 2021 by asset class are as follows: (In thousands) Total Level 1 Level 2 Equity securities: Mutual funds—equities $ 271,811 $ — $ 271,811 Fixed income investments: Mutual funds—bonds 613,243 — 613,243 Insurance contracts 5,684 — 5,684 Other: Other mutual funds 75,651 — 75,651 Cash and money market accounts 6,863 6,863 — Total $ 973,252 $ 6,863 $ 966,389 The fair values of the Company's international defined benefit pension plans' assets at December 31, 2020 by asset class are as follows: (In thousands) Total Level 1 Level 2 Equity securities: Mutual funds—equities $ 306,959 $ — $ 306,959 Fixed income investments: Mutual funds—bonds 467,285 — 467,285 Insurance contracts 6,282 — 6,282 Other: Other mutual funds 174,921 — 174,921 Cash and money market accounts 1,730 1,730 — Total $ 957,177 $ 1,730 $ 955,447

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income (loss) from continuing operations before income taxes and equity income as reported on the Consolidated Statements of Operations consists of the following: (In thousands) 2021 2020 2019 U.S. $ (34,462) $ (87,315) $ (38,969) International 71,968 33,095 70,034 Total income (loss) from continuing operations before income taxes and equity income $ 37,506 $ (54,220) $ 31,065
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense (benefit) as reported on the Consolidated Statements of Operations consists of the following: (In thousands) 2021 2020 2019 Income tax expense (benefit): Currently payable: U.S. federal $ — $ (12,116) $ 902 U.S. state 507 468 220 International 22,295 16,518 21,132 Total income taxes currently payable 22,802 4,870 22,254 Deferred U.S. federal (4,594) (10,558) (9,367) Deferred U.S. state (18) (3,078) (2,575) Deferred international (9,101) 93 2,416 Total income tax expense (benefit) from continuing operations $ 9,089 $ (8,673) $ 12,728
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the normal expected statutory U.S. federal income tax expense (benefit) to the actual Income tax expense (benefit) from continuing operations as reported on the Consolidated Statements of Operations is as follows: (In thousands) 2021 2020 2019 U.S. federal income tax expense (benefit), at statutory tax rate of 21% $ 7,877 $ (11,386) $ 6,523 U.S. state income taxes, net of federal income tax benefit (310) (2,015) (1,290) U.S. other domestic deductions and credits (415) (1,312) (596) Difference in effective tax rates on international earnings and remittances 4,488 7,872 7,536 Uncertain tax position contingencies and settlements 783 289 310 Changes in realization on beginning of the year deferred tax assets (5,035) (1,501) 2,343 U.S. non-deductible expenses 936 2,300 2,461 Impact of U.S. tax reform — — 1,644 Net operating loss carryback (2,696) — State deferred tax rate changes 592 (40) (3,354) Employee share-based payments 173 (184) (2,817) Other, net — — (32) Total income tax expense (benefit) from continuing operations $ 9,089 $ (8,673) $ 12,728
Schedule of Deferred Tax Assets and Liabilities	The income tax effects of the temporary differences giving rise to the Company's deferred tax assets and liabilities at December 31, 2021 and 2020 are as follows: 2021 (a) 2020 (a) (In thousands) Asset Liability Asset Liability Depreciation and amortization $ — $ 80,278 $ — $ 87,681 Right-of-use assets 25,759 23,406 Operating lease liabilities 25,431 22,868 Expense accruals 24,949 — 22,136 — Inventories 3,400 — 2,721 — Provision for receivables 5,504 — 4,903 — Deferred revenue — 4,124 — 4,425 Operating loss carryforwards 65,935 — 66,703 — Tax credit carryforwards 18,608 — 15,630 — Pensions 23,298 — 49,740 — Currency adjustments 5,075 — 4,829 — Deferred financing costs 359 — — 269 Section 163(j) disallowed interest expense 4,843 — — — Post-retirement benefits 335 — 340 — Stock based compensation 7,396 — 6,696 — Other 1,470 — 1,954 — Subtotal 186,603 110,161 198,520 115,781 Valuation allowance (92,385) — (108,563) — Total deferred income taxes $ 94,218 $ 110,161 $ 89,957 $ 115,781 (a) Does not include approximately $1.1 billion of statutory loss carryforwards within Luxembourg for which the Company considers the utilization of these attributes remote and as such no deferred tax asset or corresponding valuation allowance has been recorded.
Summary of Income Tax Contingencies	A reconciliation of the change in the unrecognized income tax benefits balance from January 1, 2019 to December 31, 2021 is as follows: (In thousands) Unrecognized Deferred Unrecognized Balances, January 1, 2019 $ 2,422 $ (26) $ 2,396 Additions for tax positions related to the current year (includes currency translation adjustment) 414 (7) 407 Additions for tax positions related to prior years (includes currency translation adjustment) 681 — 681 Statutes of limitation expirations (326) 2 (324) Settlements (62) 9 (53) Balance at December 31, 2019 3,129 (22) 3,107 Additions for tax positions related to the current year (includes currency translation adjustment) 596 (2) 594 Other reductions for tax positions related to prior years (771) — (771) Statutes of limitation expirations (58) 2 (56) Balance at December 31, 2020 2,896 (22) 2,874 Additions for tax positions related to the current year (includes currency translation adjustment) 316 (1) 315 Additions for tax positions related to prior years (includes currency translation adjustment) 500 — 500 Statutes of limitation expirations (585) 1 (584) Total unrecognized income tax benefits that, if recognized, would impact the effective income tax rate at December 31, 2021 $ 3,127 $ (22) $ 3,105

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
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) December 31 December 31 Current portion of environmental liabilities (a) $ 7,338 $ 6,862 Long-term environmental liabilities 28,435 29,424 Total environmental liabilities $ 35,773 $ 36,286 (a) The current portion of environmental liabilities is included in the caption Other current liabilities on the Consolidated Balance Sheets.

Capital Stock (Tables)

Capital Stock (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Common Stock Outstanding Roll Forward	The following table summarizes the Company's common stock: Shares Treasury Outstanding Outstanding, January 1, 2019 113,473,951 33,928,928 79,545,023 Shares issued for vested restricted stock units 321,965 125,863 196,102 Shares issued for vested performance units 908,566 379,353 529,213 Stock appreciation rights exercised 15,865 4,619 11,246 Treasury shares purchased — 1,766,826 (1,766,826) Outstanding, December 31, 2019 114,720,347 36,205,589 78,514,758 Shares issued for vested restricted stock units 229,413 91,188 138,225 Shares issued for vested performance stock units 471,412 206,261 265,151 Stock appreciation rights exercised 8,870 2,634 6,236 Outstanding, December 31, 2020 115,430,042 36,505,672 78,924,370 Shares issued for vested restricted stock units 305,535 112,275 193,260 Shares issued for vested performance stock units 124,077 54,950 69,127 Stock appreciation rights exercised 46,739 17,950 28,789 Outstanding, December 31, 2021 115,906,393 36,690,847 79,215,546
Schedule of Earnings Per Share, Basic and Diluted	The following is a reconciliation of the average shares of common stock used to compute basic earnings per common share to the shares used to compute diluted earnings per common share as shown on the Consolidated Statements of Operations: (In thousands, except per share data) 2021 2020 2019 Income (loss) from continuing operations attributable to Harsco Corporation common stockholders $ 22,137 $ (49,727) $ 10,311 Weighted-average shares outstanding—basic 79,234 78,939 79,632 Dilutive effect of stock-based compensation 1,055 — 1,743 Weighted-average shares outstanding—diluted 80,289 78,939 81,375 Income (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders: Basic $ 0.28 $ (0.63) $ 0.13 Diluted $ 0.28 $ (0.63) $ 0.13
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 or the market conditions for the performance share units were not met: (In thousands) 2021 2020 2019 Restricted stock units — 714 — Stock appreciation rights 826 2,474 491 Performance share units 865 887 124

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of restricted stock units issued and compensation expense	The following table summarizes RSUs issued and the compensation expense from continuing operations recorded for the years ended December 31, 2021, 2020, and 2019: RSUs (a) Weighted Average Fair Value Expense (Dollars in thousands, except per unit) 2021 2020 2019 Directors: 2018 43,821 20.54 — — 280 2019 14,211 25.33 — 120 240 2020 34,986 10.29 120 240 — 2021 23,224 21.53 333 — — Employees: 2016 536,773 7.09 — — 245 2017 286,251 13.70 — 85 763 2018 242,791 19.93 142 706 1,064 2019 270,864 22.25 1,239 1,270 1,524 2020 522,087 8.22 1,093 1,244 — 2021 343,125 18.62 1,892 — — Total $ 4,819 $ 3,665 $ 4,116 (a) Represents number of awards originally issued.
Schedule of restricted stock unit activity	RSU activity for the year ended December 31, 2021 was as follows: Number of Shares Weighted Average Non-vested at December 31, 2020 686,287 $ 11.84 Granted 366,349 18.81 Vested (307,543) 13.33 Forfeited (32,249) 14.16 Non-vested at December 31, 2021 712,844 14.68
Schedule of Stock Appreciation Rights award activity	SARs activity for the year ended December 31, 2021 was as follows: Number of Shares Weighted Average Exercise Price Aggregate Intrinsic Value (in millions) (b) Outstanding, December 31, 2020 2,401,131 $ 14.37 $ 11.7 Granted 184,641 18.58 Exercised (107,413) 10.81 Forfeited/Expired (84,304) 17.31 Outstanding, December 31, 2021 2,394,055 14.75 8.6
Schedule of nonvested awards activity	The following table summarizes information concerning outstanding and exercisable SARs at December 31, 2021: SARs Outstanding SARs Exercisable Range of exercisable prices Vested Non-vested Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Life in Years Number Exercisable Weighted-Average Exercise Price per Share $7.00 - $14.89 807,168 443,256 $ 9.87 6.53 807,168 $ 9.48 $16.53 - $22.70 727,909 221,624 19.12 5.31 727,909 19.01 $23.25 - $26.92 194,098 — 24.80 2.61 194,098 24.80 1,729,175 664,880 14.75 5.73 1,729,175 15.21
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock appreciation rights valuation assumptions	The fair value of each SAR grant was estimated on the grant date using a Black-Scholes pricing model with the following assumptions: Risk-free Interest rate Dividend Yield Expected Life (Years) Volatility SAR Grant Price Fair Value of SAR March 2019 Grant 2.52 % — % 6.0 46.2 % 22.51 10.62 July 2019 Grant 1.84 % — % 6.0 47.1 % 27.39 12.80 March 2020 Grant 0.76 % — % 6.0 45.2 % 10.29 3.03 October 2020 Grant 0.44 % — % 6.0 60.3 % 14.89 8.12 March 2021 Grant 0.91 % — % 6.0 61.9 % 18.58 10.48
Schedule of weighted-average grant-date fair value of unvested options	Weighted-average grant date fair value of non-vested SARs for the year ended December 31, 2021 was as follows: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares, December 31, 2020 877,947 $ 4.50 Granted 184,641 10.48 Vested (348,340) 5.33 Forfeited (49,368) 5.77 Non-vested shares, December 31, 2021 664,880 5.63
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock appreciation rights valuation assumptions	The fair value of PSUs granted was estimated on the grant date using a Monte Carlo pricing model with the following assumptions: Risk-free Interest rate Dividend Yield Expected Life (Years) Volatility Fair Value of PSU March 2019 Grant 2.48 % — % 2.82 33.8 % 29.04 July 2019 Grant 1.75 % — % 2.50 34.3 % 40.07 August 2019 Grant 1.57 % — % 2.41 34.9 % 23.38 March 2020 Grant 0.56 % — % 2.81 36.0 % 4.40 October 2020 Grant 0.17 % — % 2.20 53.7 % 17.01 March 2021 Grant 0.25 % — % 2.83 50.7 % 25.38
Schedule of weighted-average grant-date fair value of unvested options	A summary of the Company's non-vested PSU activity during the year ending December 31, 2021 was as follows: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares, December 31, 2020 696,318 $ 11.85 Granted 316,959 25.38 Forfeited (44,839) 15.47 Vested, not issued (c) (214,645) 26.84 Non-vested shares, December 31, 2021 753,793 13.05 (c) The measurement period for PSUs issued in 2019 ended on December 31, 2021 and these shares vested but will not be issued until the Board certifies the measurement period results in early 2022. A total of 0 shares are expected to be issued.

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of outstanding derivative contracts recorded as assets and liabilities	The fair value of outstanding derivative contracts recorded as assets and liabilities on the 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 December 31, 2021 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 719 $ 1,405 $ 2,124 Total $ 719 $ 1,405 $ 2,124 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 560 $ 2,905 $ 3,465 Interest rate swaps Other current liabilities 4,157 — 4,157 Total $ 4,717 $ 2,905 $ 7,622 (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 December 31, 2020 Asset derivatives (Level 2): Foreign currency exchange forward contracts Other current assets $ 900 $ 2,777 $ 3,677 Total $ 900 $ 2,777 $ 3,677 Liability derivatives (Level 2): Foreign currency exchange forward contracts Other current liabilities $ 950 $ 4,098 $ 5,048 Interest rate swaps Other current liabilities 3,959 — 3,959 Interest rate swaps Other liabilities 3,718 — 3,718 Total $ 8,627 $ 4,098 $ 12,725
Derivative Instruments, Gain (Loss) [Table Text Block]	The effect of derivative instruments on the Consolidated Statements of Operations and the Consolidated Statements of Comprehensive Income (Loss) was as follows: Derivatives Designated as Hedging Instruments Amount Recognized in Location of Amount Reclassified Amount Reclassified from (In thousands) 2021 2020 2019 2021 2020 2019 Foreign currency exchange forward contracts $ — $ — $ (41) Product revenues/Cost of services sold $ — $ — $ 44 Foreign currency exchange forward contracts 309 (930) (1,186) Income (loss) from discontinued businesses (129) (1,026) (550) Interest rate swaps — — — Income (loss) from discontinued businesses — — 2,741 Interest rate swaps (42) (3,889) (8,209) Interest expense 3,474 2,589 (520) CCIRs(a) — 39 (42) Interest expense — 1,015 1,219 $ 267 $ (4,780) $ (9,478) $ 3,345 $ 2,578 $ 2,934 (a) Amounts represent changes in foreign currency translation related to balances in AOCI.
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The location and amount of gain (loss) recognized on the Consolidated Statements of Operations: 2021 (in thousands) Interest Expense Income (Loss) from Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (63,235) $ (25,863) Interest rate swaps: Gain or (loss) reclassified from AOCI into income (3,474) — Gain or (loss) reclassified from AOCI into income as a result that a forecasted transaction Amount recognized in earnings due to ineffectiveness 89 — Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income — 129 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — 62 Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach — (2) 2020 (in thousands) Interest Expense Income (Loss) From Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ (58,196) $ 20,350 Interest rate swaps: Gain or (loss) reclassified from AOCI into income (2,589) — Foreign exchange contracts: Gain or (loss) reclassified from AOCI into income — 1,026 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — 197 Amount excluded from the effectiveness testing recognized in earnings based on an amortization approach — 31 CCIRs: Gain or (loss) reclassified from AOCI into income (1,015) — 2019 (in thousands) Cost of Services Sold Interest Expense Income (Loss) From Discontinued Businesses Total amounts of line items presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ 822,043 $ (34,024) $ 52,937 Interest rate swaps: Gain or (loss) reclassified from AOCI into income — 520 — Gain or (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 (44) — 550 Amount excluded from effectiveness testing recognized in earnings based on changes in fair value — — 509 CCIRs: Gain or (loss) reclassified from AOCI into income — (1,219) —
Derivatives Not Designated as Hedging Instruments	Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives for the Twelve Months Ended December 31(b) (In thousands) 2021 2020 2019 Foreign currency exchange forward contracts Cost of services and products sold $ 10,761 $ (9,052) $ 6,807 (b) These gains (losses) offset amounts recognized in cost of service and products sold principally as a result of intercompany or third-party foreign currency exposures.

Information by Segment and Ge_2

Information by Segment and Geographic Area (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	Countries with revenues from unaffiliated customers or net property, plant and equipment of ten percent or more of the consolidated totals (in at least one period presented) are as follows: Information by Geographic Area (a) Revenues from Unaffiliated Customers Twelve Months Ended December 31 (In thousands) 2021 2020 2019 U.S. $ 1,008,689 $ 830,699 $ 420,956 U.K. 117,529 116,425 126,660 All Other 722,181 586,909 656,753 Totals including Corporate $ 1,848,399 $ 1,534,033 $ 1,204,369 (a) Revenues are attributed to individual countries based on the location of the facility generating the revenue.
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]	Property, Plant and Equipment, Net December 31 (In thousands) 2021 2020 U.S. $ 267,174 $ 253,994 China 108,496 109,617 All Other 278,243 266,743 Totals including Corporate $ 653,913 $ 630,354
Schedule of Segment Operating Information by Segment	Operating Information by Segment: Twelve Months Ended December 31 (In thousands) 2021 2020 2019 Revenues ( b ) Harsco Environmental $ 1,068,083 $ 914,445 $ 1,034,847 Harsco Clean Earth 780,316 619,588 169,522 Total Revenues $ 1,848,399 $ 1,534,033 $ 1,204,369 Operating Income (Loss) ( b ) Harsco Environmental $ 103,402 $ 59,006 $ 112,298 Harsco Clean Earth 25,639 16,096 20,009 Corporate (40,665) (78,408) (55,904) Total Operating Income (Loss) $ 88,376 $ (3,306) $ 76,403 Total Assets Harsco Environmental $ 1,386,087 $ 1,322,731 $ 1,296,061 Harsco Clean Earth 1,278,472 1,279,387 745,410 Corporate 56,086 74,185 28,455 Discontinued Operations 333,263 316,984 297,541 Total Assets $ 3,053,908 $ 2,993,287 $ 2,367,467 Depreciation ( b ) Harsco Environmental $ 105,830 $ 100,971 $ 104,840 Harsco Clean Earth 19,672 17,450 4,932 Corporate 1,900 2,022 2,737 Total Depreciation $ 127,402 $ 120,443 $ 112,509 Amortization ( b ) Harsco Environmental $ 8,052 $ 7,825 $ 7,286 Harsco Clean Earth 24,180 22,814 7,923 Corporate ( c ) 2,710 2,961 2,500 Total Amortization $ 34,942 $ 33,600 $ 17,709 Capital Expenditures ( b ) Harsco Environmental $ 137,228 $ 99,056 $ 153,694 Harsco Clean Earth 18,403 12,612 5,870 Corporate 1,289 488 1,762 Total Capital Expenditures $ 156,920 $ 112,156 $ 161,326 (b) 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 Rail Segment and former Harsco Industrial Segment have been reflected as discontinued operations in the Consolidated Statement of Operations for all periods presented. See Note 3, Acquisitions and Dispositions, for additional details. (c) Amortization expense on Corporate relates to the amortization of deferred financing costs.
Reconciliation of Operating Profit (Loss) from Segments to Consolidated	Reconciliation of Segment Operating Income to Consolidated Income (Loss) From Continuing Operations Before Income Taxes and Equity Income: Twelve Months Ended December 31 (In thousands) 2021 2020 2019 Segment operating income $ 129,041 $ 75,102 $ 132,307 General Corporate expense (40,665) (78,408) (55,904) Operating income from continuing operations 88,376 (3,306) 76,403 Interest income 2,231 2,129 1,946 Interest expense (63,235) (58,196) (34,024) Defined benefit pension income (expense) 15,640 7,073 (5,556) Unused debt commitment fees, amendment fees and loss on extinguishment of debt (5,506) (1,920) (7,704) Income (loss) from continuing operations before income taxes and equity income $ 37,506 $ (54,220) $ 31,065

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2021
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: Twelve Months Ended December 31, 2021 (In thousands) Harsco Harsco Consolidated Totals Primary Geographical Markets (a)(b) : North America $ 281,124 $ 780,317 $ 1,061,441 Western Europe 442,286 — 442,286 Latin America (c) 132,349 — 132,349 Asia-Pacific 110,790 — 110,790 Middle East and Africa 81,337 — 81,337 Eastern Europe 20,196 — 20,196 Total Revenues $ 1,068,082 $ 780,317 $ 1,848,399 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 920,579 $ — $ 920,579 Ecoproducts 132,389 — 132,389 Environmental systems for aluminum dross and scrap processing 15,114 — 15,114 Waste processing and reuse solutions — 780,317 780,317 Total Revenues $ 1,068,082 $ 780,317 $ 1,848,399 Twelve Months Ended December 31, 2020 (In thousands) Harsco Environmental Segment Harsco Consolidated Totals Primary Geographical Markets (a)(b) : North America $ 249,904 $ 619,588 $ 869,492 Western Europe 377,066 — 377,066 Latin America (c) 119,457 — 119,457 Asia-Pacific 87,608 — 87,608 Middle East and Africa 63,427 — 63,427 Eastern Europe 16,983 — 16,983 Total Revenues $ 914,445 $ 619,588 $ 1,534,033 Key Product and Service Groups (a) : Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 781,060 $ — $ 781,060 Ecoproducts 120,432 — 120,432 Environmental systems for aluminum dross and scrap processing 12,953 — 12,953 Waste processing and reuse solutions — 619,588 619,588 Total Revenues $ 914,445 $ 619,588 $ 1,534,033 Twelve Months Ended December 31, 2019 (In thousands) Harsco Environmental Segment Harsco Consolidated Totals Primary Geographical Markets (b) : North America $ 294,367 $ 169,522 $ 463,889 Western Europe 386,593 — 386,593 Latin America (c) 146,040 — 146,040 Asia-Pacific 128,949 — 128,949 Middle East and Africa 60,402 — 60,402 Eastern Europe 18,496 — 18,496 Total Revenues $ 1,034,847 $ 169,522 $ 1,204,369 Key Product and Service Groups: Environmental services related to resource recovery for metals manufacturing; and related logistical services $ 888,851 $ — $ 888,851 Ecoproducts 127,874 — 127,874 Environmental systems for aluminum dross and scrap processing 18,122 — 18,122 Waste processing and reuse solutions — 169,522 169,522 Total Revenues $ 1,034,847 $ 169,522 $ 1,204,369 (a) The Company acquired ESOL in 2020 and Clean Earth in 2019. The results of both are included in the Harsco Clean Earth Segment. The operating results of the former Harsco Rail Segment and Harsco Industrial Segment have been reflected as discontinued operations in the Consolidated Statements of Operations. See Note 3, Acquisition 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 Expenses (Tables)

Other Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Other Income and Expenses [Abstract]
Schedule of other expenses (income)	The major components of this Consolidated Statements of Operations caption are as follows: (In thousands) 2021 2020 2019 Net gains Harsco Environmental Segment $ (8,902) $ (3,723) $ (6,303) Employee termination benefit costs Harsco Environmental Segment 2,852 9,389 1,254 Clean Earth Segment 433 833 1,960 Corporate 1,481 27 1,012 Total employee termination benefit costs 4,766 10,249 4,226 Other costs to exit activities Harsco Environmental Segment 640 504 970 Clean Earth Segment 23 — — Corporate — 29 196 Total other costs to exit activities 663 533 1,166 Impaired asset write-downs Harsco Environmental Segment 942 776 632 Clean Earth Segment 63 — — Total impaired asset write-downs 1,005 776 632 Contingent consideration adjustments Harsco Environmental Segment — — (8,506) Harsco Clean Earth Segment — 112 825 Corporate — 2,274 — Total contingent consideration adjustments — 2,386 (7,681) Other income (1,254) (149) (234) Total other (income) expenses, net $ (3,722) $ 10,072 $ (8,194)

Components of Accumulated Oth_2

Components of Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Components of accumulated other comprehensive loss	The components of AOCI, net of the effect of income taxes, and activity for the years ended December 31, 2021 and 2020 are 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 Loss on Marketable Securities Total Balance at December 31, 2019 (143,340) (3,717) (440,562) (3) (587,622) OCI before reclassifications 7,854 (a) (3,709) (b) (96,684) (c) (6) (92,545) Amounts reclassified from AOCI, net of tax 12,906 1,586 22,746 — 37,238 Total OCI 20,760 (2,123) (73,938) (6) (55,307) Less: OCI attributable to noncontrolling interests (2,812) — — — (2,812) OCI attributable to Harsco Corporation 17,948 (2,123) (73,938) (6) (58,119) Balance at December 31, 2020 $ (125,392) $ (5,840) $ (514,500) $ (9) $ (645,741) 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 Loss on Marketable Securities Total Balance at December 31, 2020 $ (125,392) $ (5,840) $ (514,500) $ (9) $ (645,741) OCI before reclassifications (10,994) (a) 441 (b) 69,517 (c) 31 58,995 Amounts reclassified from AOCI, net of tax 2,375 22,735 25,110 Total OCI (10,994) 2,816 92,252 31 84,105 Plus: OCI attributable to noncontrolling interests 1,497 — — 1,497 OCI attributable to Harsco Corporation (9,497) 2,816 92,252 31 85,602 Balance at December 31, 2021 $ (134,889) $ (3,024) $ (422,248) $ 22 $ (560,139) (a) Principally foreign currency fluctuation. (b) Principally net change from periodic revaluations. (c) Principally changes due to annual actuarial remeasurements and foreign currency translation.
Amounts reclassified out of accumulated other comprehensive loss	Amounts reclassified from AOCI for 2021 and 2020 are as follows: Year Ended December 31 2021 Year Ended December 31 2020 Affected Caption on the (In thousands) Amortization of defined benefit pension items (d) : Actuarial losses $ 23,657 $ 19,623 Defined benefit pension income (expense) Prior-service costs 582 511 Defined benefit pension income (expense) Pension asset transfer - discontinued businesses — 5,363 Gain on sale of discontinued businesses Settlement/curtailment losses (72) (110) Discontinued operations Settlement/curtailment losses — 18 Defined benefit pension income (expense) Total before tax 24,167 25,405 Tax benefit (1,432) (2,659) Total reclassification of defined benefit pension items, net of tax $ 22,735 $ 22,746 Recognition of cumulative foreign currency translation adjustments: Gain on substantial liquidation of subsidiaries (e) $ — $ 12,906 Other (income) expenses, net Amortization of cash flow hedging instruments: Foreign currency exchange forward contracts $ (129) $ (1,026) Discontinued operations CCIRs — 1,015 Interest expense Interest rate swaps 3,474 2,589 Interest expense Total before tax 3,345 2,578 Tax benefit (970) (992) Total reclassification of cash flow hedging instruments $ 2,375 $ 1,586 (d) These AOCI components are included in the computation of NPPC. See Note 10, Employee Benefit Plans, for additional information. (e) No tax impact.

Two-Year Summary of Quarterly R

Two-Year Summary of Quarterly Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	2021 (a) Quarterly First Second Third Fourth Revenues $ 447.3 $ 468.7 $ 470.4 $ 462.1 Gross profit (b) 89.9 93.2 95.0 79.7 Net income (loss) attributable to Harsco Corporation 0.1 13.4 7.6 (24.4) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.02) $ 0.11 $ 0.06 $ 0.13 Discontinued operations (c) 0.02 0.06 0.03 (0.43) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ 0.17 $ 0.10 (d) $ (0.31) (d) Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.02) $ 0.11 $ 0.06 $ 0.13 Discontinued operations (c) 0.02 0.06 0.03 (0.43) Diluted loss per share attributable to Harsco Corporation common stockholders $ — $ 0.17 $ 0.09 $ (0.30) 2020 (a) Quarterly First Second Third Fourth Revenues $ 320.4 $ 365.6 $ 416.6 $ 431.5 Gross profit (b) 62.3 62.1 80.5 86.8 Net income (loss) attributable to Harsco Corporation 0.1 (10.6) (9.6) (6.3) Basic earnings (loss) per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.17) $ (0.25) $ (0.12) $ (0.09) Discontinued operations (c) 0.17 0.12 — 0.01 Basic earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ (0.13) $ (0.12) $ (0.08) Diluted income per share attributable to Harsco Corporation common stockholders: Continuing operations $ (0.17) $ (0.25) $ (0.12) $ (0.09) Discontinued operations (c) 0.17 0.12 — 0.01 Diluted earnings (loss) per share attributable to Harsco Corporation common stockholders $ — $ (0.13) $ (0.12) $ (0.08) (a) Sum of the quarters may not equal the total year due to rounding. (b) Gross profit is defined as Revenues less costs and expenses associated directly with or allocated to products sold or services rendered. (c) Discontinued operations related principally to the Company's former Harsco Rail Segment. (d) Does not total due to rounding.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Restricted cash	$ 4,220	$ 3,215

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details 3) - Self-insurance - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Insurance expense from continuing operations	$ 25.6	$ 21.1	$ 12.5
Decrease in pre-tax insurance expense due to retrospective insurance reserve adjustments from continuing operations	0.2	1.3	$ 0.8
Liabilities for asserted and unasserted claims	28.3	27.3
Liabilities covered by insurance carriers	$ 4.1	$ 5.2

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Product revenues	$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Foreign currency exchange forward contracts | Maximum
Derivative [Line Items]
Maximum typical term of foreign currency forward exchange contracts (in days)									90 days

Acquisitions and Dispositions -

Acquisitions and Dispositions - Schedule of Balance Sheet from Disposal of Harsco Rail Segment (Details) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Rail liabilities included in Liabilities of assets held-for-sale	$ 161,999	$ 127,927
Discontinued Operations, Held-for-sale | Harsco Rail
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Trade accounts receivable, net	33,689	52,077
Other receivables	4,740	3,045
Inventories	103,560	112,013
Current portion of contract assets	94,597	52,240
Other current assets	25,442	27,703
Property, plant and equipment, net	39,524	37,855
Right-of-use assets, net	3,108	4,354
Goodwill	13,026	13,026
Intangible assets, net	3,081	3,449
Deferred income tax assets	6,064	4,906
Other assets	6,432	6,316
Total Rail assets included in Assets held-for-sale	333,263	316,984
Accounts payable	46,076	53,937
Accrued compensation	2,171	1,503
Current portion of operating lease liabilities	1,619	1,745
Other current liabilities	49,732	33,280
Advances on contracts	0	44,731
Current portion of advances on contracts	62,401	37,462
Operating lease liabilities	1,775	2,734
Deferred tax liabilities	5,736	4,461
Other liabilities	982	925
Total Rail liabilities included in Liabilities of assets held-for-sale	$ 170,492	$ 180,778

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Schedule of Income (Loss) from Discontinued Operations Harsco Rail (Details) - Discontinued Operations, Held-for-sale - Harsco Rail - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued businesses	$ (19,967)	$ 23,096	$ 25,406
Selling, general and administrative expenses	178	0	0
Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	32,425	31,642	30,254
Cost of products sold	17,272	23,480	21,883
Product
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	266,221	298,189	269,119
Cost of products sold	$ 251,897	$ 235,040	$ 192,310

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Summary of Cash Flow Information from Disposal of Harsco Rail Segment (Details) - Discontinued Operations, Held-for-sale - Harsco Rail - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Depreciation and amortization	$ 4,329	$ 5,450	$ 4,876
Purchases of property, plant and equipment	$ 1,406	$ 7,962	$ 15,274

Acquisitions and Dispositions_4

Acquisitions and Dispositions - Narrative (Details) - USD ($) $ in Thousands	Apr. 06, 2020	Jun. 28, 2019	Jan. 31, 2020	Nov. 30, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 01, 2019
Business Acquisition [Line Items]
Product revenues					$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Operating income from continuing operations													88,376	(3,306)	76,403
Interest Expense													63,235	58,196	34,024
Purchase of businesses, net of cash acquired													0	432,855	623,495
Proceeds from sale of businesses													0	37,219	658,414
Receivable with Imputed Interest, Face Amount			$ 40,000
Receivables, Fair Value Disclosure			34,300		32,300								32,300
Income (loss) from discontinued businesses													0	18,281	569,135
Revenues													1,848,399	1,534,033	1,204,369
Provision for Loss on Contracts					$ 33,400								$ 33,400
SBB
Business Acquisition [Line Items]
Revenues
SBB | Contract 2
Business Acquisition [Line Items]
Percentage Complete					78.00%								78.00%
Network Rail | Contract 2
Business Acquisition [Line Items]
Percentage Complete					42.00%								42.00%
Deutsche Bahn | Contract 2
Business Acquisition [Line Items]
Percentage Complete					18.00%								18.00%
Clean Earth
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Purchase price		$ 628,000
Business Combination, Additional Expense Related To Reimbursement of NOL, Fair Value													$ 8,000	11,000
Tax deductible Goodwill		16,300
Costs associated with the acquisition														15,200
Business Combination, Consideration Transferred		$ 625,000
Business Combination, Contingent Consideration Arrangements, Post-Closing Period		5 years
ESOL
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Purchase price	$ 429,000
Tax deductible Goodwill	$ 36,800
Costs associated with the acquisition													49,000	7,300
Harsco Industrial | Discontinued Operations, Held-for-sale
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Corporate Overhead															4,000
Income (loss) from discontinued businesses													0	18,281	569,135
Harsco Industrial Patterson-Kelley [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Net Gain on Disposal, After Tax				$ 33,000
Disposal Group, Net Gain on Disposal, Before Tax				41,200
Proceeds from sale of businesses				$ 60,000
Harsco Industrial IKG | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			85,000
Disposal Group, Net Gain on Disposal, After Tax			9,000
Receivable with Imputed Interest, Face Amount			40,000
Income (loss) from discontinued businesses			$ 18,400
Harsco Industrial Air-X-Changers Business [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Consideration																$ 600,000
Disposal Group, Net Gain on Disposal, After Tax																421,000
Disposal Group, Net Gain on Disposal, Before Tax																$ 527,900
Harsco Rail | Discontinued Operations, Held-for-sale
Business Acquisition [Line Items]
Disposal Group, Including Discontinued Operation, Corporate Overhead													$ 4,200	$ 4,200	$ 4,200

Acquisitions and Dispositions_5

Acquisitions and Dispositions - Summary of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	9 Months Ended	18 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2021	Apr. 06, 2020	Dec. 31, 2019	Jun. 28, 2019
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	$ 889,048	$ 889,048	$ 883,109		$ 725,343
Non-compete agreement	517,146	517,146	516,240
Clean Earth
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets			242,200			$ 261,100
ESOL
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Right-of-use assets, net				$ 56,000
Clean Earth
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	482,647	482,647	483,879		$ 330,230
Measurement Period Adjustments
Measurement period adjustment, intangible assets		(18,900)
Clean Earth | Clean Earth
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents			3,600			42,800
Trade accounts receivable, net			62,500			63,700
Other current assets			7,300			8,700
Property, plant and equipment			77,000			75,600
Right-of-use assets, net			25,800			14,400
Goodwill			330,600			313,800
Intangible assets			242,200			261,100
Other assets			1,200			4,000
Accounts payable			(23,100)			(23,000)
Other current liabilities			(19,700)			(18,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities			(45,700)			(51,200)
Operating lease liabilities			(19,500)			(11,100)
Other receivables			2,100			800
Acquisition consideration payable			0			(39,200)
Other liabilities			(8,600)			(6,500)
Total identifiable net assets			635,700			$ 635,900
Measurement Period Adjustments
Measurement period adjustment, cash and cash equivalent		(39,200)
Measurement period adjustment, trade accounts receivable, net		(1,200)
Measurement period adjustment, other receivable		1,300
Measurement period adjustment, other current assets		(1,400)
Measurement period adjustment, property, plant and equipment		1,400
Measurement period adjustment, right-of-use assets		11,400
Measurement period adjustment, other assets		(2,800)
Measurement period adjustment, acquisition consideration payable		39,200
Measurement period adjustment, other current liabilities		(1,700)
Measurement period adjustment, accounts payable		100
Measurement period adjustment, deferred income taxes		5,500
Measurement period adjustment, operating lease liabilities		(8,400)
Measurement period adjustment, other liabilities		(2,100)
Measurement period adjustment, intangible assets		(18,900)
Measurement period adjustment, goodwill		16,800
Total identifiable net assets		$ (200)
Clean Earth | ESOL
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents			400	400
Trade accounts receivable, net			122,600	124,100
Inventory			5,000	5,000
Other current assets			0	700
Property, plant and equipment			101,400	105,300
Right-of-use assets, net			56,000	56,000
Goodwill			153,300	152,000
Intangible assets			161,000	161,000
Other assets			200	200
Accounts payable			(50,100)	(48,600)
Accrued expenses			(19,300)	(17,500)
Current portion of operating lease liabilities			(16,600)	(16,600)
Other current liabilities			(6,600)	(6,400)
Environmental liabilities			(24,400)	(24,400)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities			(17,000)	(15,500)
Operating lease liabilities			(39,400)	(39,400)
Non-compete agreement			2,500	2,500
Total identifiable net assets			426,500	436,300
Business Acquisitions, Purchase Price Allocation			$ 429,000	$ 438,800
Measurement Period Adjustments
Measurement period adjustment, cash and cash equivalent	0
Measurement period adjustment, trade accounts receivable, net	(1,500)
Measurement period adjustment, environmental liabilities	0
Measurement period adjustment, other current assets	(700)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Purchase Price Allocation	(9,800)
Measurement period adjustment, current portion of operating lease liabilities	0
Measurement period adjustment, property, plant and equipment	(3,900)
Measurement period adjustment, right-of-use assets	0
Measurement period adjustment, inventory	0
Measurement period adjustment, other assets	0
Measurement period adjustment, other current liabilities	(200)
Measurement period adjustment, accrued expenses	(1,800)
Measurement period adjustment, accounts payable	1,500
Measurement period adjustment, deferred income taxes	(1,500)
Measurement period adjustment, operating lease liabilities	0
Measurement period adjustment, intangible assets	0
Measurement period adjustment, goodwill	1,300
Total identifiable net assets	$ (9,800)

Acquisitions and Dispositions_6

Acquisitions and Dispositions - Summary of Intangible Assets and Amortization Periods (Details) - USD ($) $ in Thousands	Jun. 28, 2019	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2021	Apr. 06, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Non-compete agreement		$ 517,146	$ 517,146	$ 516,240
Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Non-compete agreement		308,705	308,705	309,069
Air rights
Acquired Finite-Lived Intangible Assets [Line Items]
Non-compete agreement		26,139	26,139	26,139
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Non-compete agreement		$ 30,779	30,779	30,738
Clean Earth
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Permits			(6,000)
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Customer Relationships			(12,900)
Measurement Period Adjustments			(18,900)
Clean Earth
Acquired Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets	$ 261,100			242,200
Clean Earth | Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period	18 years
Total identifiable intangible assets	$ 176,100			170,100
Clean Earth | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period	8 years
Total identifiable intangible assets	$ 33,400			20,500
Clean Earth | Air rights
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period	27 years
Total identifiable intangible assets	$ 25,600			25,600
Clean Earth | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period	12 years
Total identifiable intangible assets	$ 26,000			26,000
Clean Earth | Clean Earth
Acquired Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets	$ 261,100			242,200
Measurement Period Adjustments			$ (18,900)
ESOL | Permits
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period		22 years
Total identifiable intangible assets				138,000	$ 138,000
ESOL | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period		10 years
Total identifiable intangible assets				23,000	23,000
ESOL | Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization Period		4 years
ESOL | Clean Earth
Acquired Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets				161,000	161,000
Measurement Period Adjustments		$ 0
Non-compete agreement				2,500	2,500
Business Combination, Recognized Identifiable Intangible Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles, Including Non-Compete				$ 163,500	$ 163,500
ESOL | Clean Earth | Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Permits		0
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Customer Relationships		0
Measurement Period Adjustments		0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments, Intangibles, Including Non-Compete		$ 0

Acquisitions and Dispositions_7

Acquisitions and Dispositions - Summary of Key Financial Information From Disposal of Harsco Industrial Segment (Details) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Income (loss) from discontinued businesses		$ 0	$ 18,281	$ 569,135
Income (loss) from discontinued businesses		(25,863)	20,350	52,937
Loss on early extinguishment of debt		2,668	0	5,314
Air-cooled heat exchangers
Business Acquisition [Line Items]
Loss on early extinguishment of debt			(5,300)
Harsco Industrial | Discontinued Operations, Held-for-sale
Business Acquisition [Line Items]
Total revenues		0	10,203	306,972
Cost of products sold		0	8,082	224,811
Income (loss) from discontinued businesses		0	18,281	569,135
Income (loss) from discontinued businesses		(3,510)	(1,578)	27,823
Selling, general and administrative expenses		3,510	2,695	8,429
Disposal Group, Including Discontinued Operation, Interest Expense		0	0	11,237
Loss on early extinguishment of debt		0	0	(5,314)
Interest rate swaps | Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member]
Business Acquisition [Line Items]
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ (2,700)	$ 0	$ (2,700)	$ (2,741)

Accounts Receivable and Note _3

Accounts Receivable and Note Receivable - Schedule of Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Receivables [Abstract]
Trade accounts receivable	$ 385,143	$ 362,801
Less: Allowance for doubtful accounts	(7,262)	(7,488)
Trade accounts receivable, net	377,881	355,313
Other receivables	$ 33,059	$ 31,208

Accounts Receivable and Note _4

Accounts Receivable and Note Receivable (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jan. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 385,143,000	$ 362,801,000
Accounts Receivable Greater than 12 Months Reserved	5,400,000
Receivable with Imputed Interest, Face Amount			$ 40,000,000
Note Receivable; Interest Rate; Stated percentage			2.50%
Receivables, Fair Value Disclosure	32,300,000		$ 34,300,000
Proceeds from Collection of Notes Receivable	6,400,000
Receivable with Imputed Interest, Net Amount	31,025,000	$ 35,806,000
Greater than 12 months
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 8,000,000
Harsco Industrial IKG | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			85,000,000
Receivable with Imputed Interest, Face Amount			$ 40,000,000

Accounts Receivable and Note _5

Accounts Receivable and Note Receivable - Schedule of Changes in Provisions For Allowance For Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Provision for expected credit losses and doubtful accounts related to trade accounts receivable	$ 589	$ 1,961	$ 7,123

Accounts Receivable - Schedule

Accounts Receivable - Schedule of Fair Value of Notes Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Receivables [Abstract]
Receivable with Imputed Interest, Net Amount	$ 31,025	$ 35,806

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Inventories
Finished goods	$ 8,323	$ 7,749
Work-in-process	5,393	2,795
Raw materials and purchased parts	21,188	20,259
Stores and supplies	35,589	30,198
Total inventories	70,493	61,001
Valued at lower of cost or market:
LIFO basis	14,133	14,690
FIFO basis	7,567	5,485
Average cost basis	48,793	40,826
Total inventories	70,493	61,001
Excess of inventories valued at current costs over LIFO	13,000	13,000
Change in income as a result of LIFO basis inventory valuation over FIFO basis valuation	$ 0	$ 0

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 1,882,303	$ 1,868,199
Less: Accumulated depreciation	(1,228,390)	(1,237,845)
Property, plant and equipment, net	653,913	630,354
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	73,067	73,237
Land improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 16,970	17,500
Land improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Land improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	20 years
Buildings and improvements
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 221,236	224,909
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	30 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 1,507,214	1,512,966
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	20 years
Uncompleted construction
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 63,816	$ 39,587

Property, Plant and Equipment -

Property, Plant and Equipment - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 653,913	$ 630,354
China
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	108,496	$ 109,617
Harsco Environmental | China
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 20,000

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 889,048	$ 725,343
Changes to goodwill	1,232	153,897
Foreign currency translation	(7,171)	9,808
Balance at the end of the period	883,109	889,048
Harsco Environmental
Goodwill [Roll Forward]
Balance at the beginning of the period	406,401	395,113
Changes to goodwill	0	1,480
Foreign currency translation	(7,171)	9,808
Balance at the end of the period	399,230	406,401
Clean Earth
Goodwill [Roll Forward]
Balance at the beginning of the period	482,647	330,230
Changes to goodwill	1,232	(152,417)
Foreign currency translation	0	0
Balance at the end of the period	$ 483,879	$ 482,647

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	$ 516,240	$ 517,146
Accumulated Amortization	113,439	82,030
Intangible assets, net	402,801	435,116
Amortization expense for intangible assets	32,000	30,600	$ 15,200
Estimated amortization expense for the next five years
2022	31,600
2023	31,600
2024	31,100
2025	30,900
2026	28,900
Customer related
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	104,322	105,222
Accumulated Amortization	54,057	46,267
Permits
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	309,069	308,705
Accumulated Amortization	34,822	18,955
Technology related
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	39,886	40,274
Accumulated Amortization	13,415	9,654
Trade names
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	30,738	30,779
Accumulated Amortization	6,842	4,272
Air rights
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	26,139	26,139
Accumulated Amortization	1,675	1,044
Patents
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	179	192
Accumulated Amortization	138	139
Non-compete agreement
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	2,500	2,500
Accumulated Amortization	1,094	469
Other
Finite-Lived Intangible Assets [Line Items]
Non-compete agreement	3,407	3,335
Accumulated Amortization	$ 1,396	$ 1,230

Debt and Credit Agreements - Sc

Debt and Credit Agreements - Schedule of Long Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Long-term Debt	$ 1,369,672	$ 1,284,765
Long-term Debt, Gross	1,387,889	1,300,532
Less: deferred financing costs	18,217	15,767
Current maturities of long-term debt	10,226	13,576
Long-term debt	1,359,446	1,271,189
Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term Debt	$ 362,000	$ 281,000
Debt, Weighted Average Interest Rate	2.50%	2.80%
New Term Loan
Line of Credit Facility [Line Items]
Long-term Debt	$ 497,500	$ 0
Debt, Weighted Average Interest Rate	2.75%
Term Loan A
Line of Credit Facility [Line Items]
Long-term Debt	$ 0	$ 280,000
Debt Instrument, Interest Rate, Stated Percentage		3.50%
Term Loan B
Line of Credit Facility [Line Items]
Long-term Debt	$ 0	$ 218,188
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Senior Notes | Revolving Credit Facility
Line of Credit Facility [Line Items]
Current maturities of long-term debt	$ 5,000	10,500
Notes Payable, Other Payables
Line of Credit Facility [Line Items]
Long-term Debt	$ 28,389	$ 21,344
Debt, Weighted Average Interest Rate	4.70%	5.00%
5.75% notes due May 15,2018 | Senior Notes
Line of Credit Facility [Line Items]
Long-term Debt	$ 500,000	$ 500,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%

Debt and Credit Agreements - _2

Debt and Credit Agreements - Schedule of Maturities of Long Term Debt (Details) $ in Thousands	Dec. 31, 2021USD ($)
Maturities of Long-term Debt [Abstract]
2023	$ 17,331
2024	9,351
2025	7,560
2026	$ 368,558

Debt and Credit Agreements - Na

Debt and Credit Agreements - Narrative (Details) $ in Thousands	12 Months Ended			21 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Feb. 22, 2022
Line of Credit Facility [Line Items]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	$ 60,900	$ 59,500	$ 27,600
Long-term Debt	1,369,672	1,284,765
Debt Issuance Costs	18,217	15,767
Payments of Financing Costs	7,828	1,928	11,272
Short-term borrowings	$ 7,748	$ 7,450
Short-term Debt, Weighted Average Interest Rate, at Point in Time	3.30%	3.40%
Senior Unsecured Notes 5.75%, Due 2027 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.75%
New Term Loan
Line of Credit Facility [Line Items]
Long-term Debt	$ 497,500	$ 0
Principle amount	$ 500,000
Debt Instrument, Quarterly Amortization Rate	0.25%
New Term Loan | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
New Term Loan | LIBOR
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread On Variable Rate, Floor	0.50%
Basis spread on variable rate	2.25%
Term Loan A
Line of Credit Facility [Line Items]
Long-term Debt	$ 0	$ 280,000
Debt Instrument, Interest Rate, Stated Percentage		3.50%
Term Loan B
Line of Credit Facility [Line Items]
Long-term Debt	$ 0	$ 218,188
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Senior Notes
Line of Credit Facility [Line Items]
Write off of Deferred Debt Issuance Cost	$ 2,700
Debt Related Commitment Fees and Debt Issuance Costs	5,500	1,900	1,000
Capitalized Debt Issuance Fee	7,800
Senior Notes | 5.75% notes due May 15,2018
Line of Credit Facility [Line Items]
Long-term Debt	$ 500,000	500,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Notes Payable, Other Payables
Line of Credit Facility [Line Items]
Long-term Debt	$ 28,389	21,344
Bridge Loan [Member]
Line of Credit Facility [Line Items]
Payments of Financing Costs			$ 6,700
Credit Agreement
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 700,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant	5.75
Long-term Debt	$ 362,000	$ 281,000
Debt Instrument, Basis Spread On Variable Rate, Floor	0.00%
Revolving Credit Facility | Subsequent Event
Line of Credit Facility [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant, increase (decrease) related to divesture of business								(0.25)
Threshold net debt to consolidated adjusted EBITDA ratio covenant								4
Revolving Credit Facility | Forecast
Line of Credit Facility [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant				4	4	4.50	5.75
Net debt to consolidated adjusted EBITDA ratio covenant, quarterly increase (decrease)				(0.25)
Revolving Credit Facility | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Revolving Credit Facility | Minimum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Revolving Credit Facility | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Revolving Credit Facility | Maximum | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.50%

Debt and Credit Agreements - Ou

Debt and Credit Agreements - Outstanding Amounts Under Revolving Credit Facility (Details) - Line of Credit [Member] $ in Thousands	Dec. 31, 2021USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 308,176
Line of Credit Facility, Maximum Borrowing Capacity	700,000
Long-term Line of Credit	362,000
Letters of Credit Outstanding, Amount	$ 29,824

Leases - Supplemental Income St

Leases - Supplemental Income Statement Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Finance Lease, Right-of-Use Asset, Amortization	$ 2,510	$ 1,523	$ 1,234
Finance Lease, Interest Expense	495	184	50
Operating Lease, Cost	32,544	28,537	13,754
Variable Lease, Cost	47,780	40,953	22,201
Sublease Income	(53)	(202)	(198)
Lease, Cost	$ 83,276	$ 70,995	$ 37,041

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 06, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 33,645	$ 28,057	$ 15,143
Finance Lease, Interest Payment on Liability	2,847	1,367	1,317
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	42,442	69,044	65,525
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 11,495	$ 6,220	$ 2,658
ESOL
Lessee, Lease, Description [Line Items]
Right-of-use assets, net				$ 56,000

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Right-of-use assets, net	$ 101,576	$ 92,495
Operating Lease, Liability, Current	25,590	23,117
Operating Lease, Liability, Noncurrent	$ 74,571	$ 67,126
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Finance Lease, Right-of-Use Asset	$ 17,185	$ 8,434
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current maturities of long-term debt	Current maturities of long-term debt
Finance Lease, Liability, Current	$ 3,756	$ 1,683
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt	Long-term debt
Finance Lease, Liability, Noncurrent	$ 13,736	$ 6,867
Operating Lease, Right-of-Use Assets, Out Of Period Adjustment	15,000
Operating Lease, Liability, Out Of Period Adjustment	$ 15,000

Leases - Supplemental Lease Inf

Leases - Supplemental Lease Information (Details)	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	7 years 1 month 20 days	8 years 2 months 19 days
Finance Lease, Weighted Average Remaining Lease Term	5 years 10 months 17 days	8 years 2 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	5.90%	6.10%
Finance Lease, Weighted Average Discount Rate, Percent	4.60%	5.10%

Leases - Schedule of Future Lea

Leases - Schedule of Future Lease Maturities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	$ 30,347
Finance Lease, Liability, Payments, Due Next Twelve Months	4,483
Lessee, Operating Lease, Liability, Payments, Due Year Two	24,959
Finance Lease, Liability, Payments, Due Year Two	4,311
Lessee, Operating Lease, Liability, Payments, Due Year Three	18,612
Finance Lease, Liability, Payments, Due Year Three	3,901
Lessee, Operating Lease, Liability, Payments, Due Year Four	12,923
Finance Lease, Liability, Payments, Due Year Four	2,834
Lessee, Operating Lease, Liability, Payments, Due Year Five	8,641
Finance Lease, Liability, Payments, Due Year Five	1,733
Lessee, Operating Lease, Liability, Payments, Due after Year Five	31,890
Finance Lease, Liability, Payments, Due after Year Five	3,078
Lessee, Operating Lease, Liability, Payments, Due	127,372
Finance Lease, Liability, Payment, Due	20,340
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(27,211)
Finance Lease, Liability, Undiscounted Excess Amount	(2,848)
Operating Lease, Liability	100,161
Finance Lease, Liability	$ 17,492

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Leases [Abstract]
Operating And Finance Leases, Excluding Short Term Leases, Weighted-Average Remaining Lease Term	29 years
Operating And Finance Leases, Excluding Short Term Leases, Renewal Option	10 years
Estimated ROU Assets And Lease Liabilities To Be Recognized	$ 17,000

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - Pension Plan - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
U.S. Plans
Defined Contribution Plan [Abstract]
Discretionary contributions	$ 0	$ 0	$ 0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0	39,000
Interest cost	4,813,000	7,381,000	10,551,000
Expected return on plan assets	(12,199,000)	(11,368,000)	(10,297,000)
Recognized prior service costs	0	0	0
Recognized losses	5,538,000	5,100,000	5,585,000
Settlement/curtailment loss (gain)	0	0	129,000
Defined benefit plans pension cost	(1,848,000)	1,113,000	6,007,000
Multiemployer plans	640,000	620,000	727,000
Defined contribution plans	5,660,000	4,769,000	2,523,000
Net periodic pension cost, U.S. Plans	$ 4,452,000	6,502,000	9,257,000
U.S. Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	4.00%
International Plans
Defined Contribution Plan [Abstract]
Additional contribution towards insurance and administrative costs (as a percent)	2.00%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1,805,000	1,642,000	1,308,000
Interest cost	12,652,000	17,599,000	22,148,000
Expected return on plan assets	(45,018,000)	(41,013,000)	(37,218,000)
Recognized prior service costs	582,000	512,000	326,000
Recognized losses	18,119,000	14,723,000	14,345,000
Settlement/curtailment loss (gain)	(6,000)	18,000	19,000
Defined benefit plans pension cost	(11,866,000)	(6,519,000)	928,000
Multiemployer plans	1,035,000	969,000	1,167,000
Defined contribution plans	4,196,000	3,994,000	5,349,000
Net periodic pension cost, International Plans	$ (6,635,000)	$ (1,556,000)	$ 7,444,000
International Plans | Maximum
Defined Contribution Plan [Abstract]
Employer matching contribution (as a percent)	6.00%

Employee Benefit Plans (Detai_2

Employee Benefit Plans (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent liabilities	$ 93,693	$ 231,335
Liabilities of assets held-for-sale	$ 8,492	$ 52,851
Pension Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rates	1.60%	2.40%	3.20%
Expected long-term rates of return on plan assets	5.10%	5.60%	5.90%
Expected long-term rates of return on plan assets for next year (as a percent)	4.70%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rates	2.10%	1.60%
U.S. Plans | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 296,660	$ 294,693
Service cost	0	0	$ 39
Interest cost	4,813	7,381	10,551
Plan participants' contributions	0	0
Amendments	0	0
Actuarial loss	(8,063)	25,212
Settlements/curtailments	0	0
Benefits paid	(16,403)	(17,675)
Effect of foreign currency	0	0
Change in benefit obligation, Acquisition	0	(12,951)
Benefit obligation at end of year	277,007	296,660	294,693
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	226,125	226,268
Actual return on plan assets	19,005	24,975
Employer contributions	4,219	3,528
Plan participants' contributions	0	0
Settlements/curtailments	0	0
Benefits paid	(16,402)	(17,675)
Effect of foreign currency	0	0
Acquisitions/divestitures	0	(10,971)
Fair value of plan assets at end of year	232,947	226,125	$ 226,268
Funded status at end of year	(44,060)	(70,535)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent assets	0	0
Current liabilities	1,999	1,970
Noncurrent liabilities	42,061	68,565
Total accumulated other comprehensive loss before tax	114,874	135,281
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss	114,874	135,281
Prior service cost	0	0
Total accumulated other comprehensive loss before tax	114,874	$ 135,281
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Estimate of expected contributions in next fiscal year	2,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	27,200
2022	16,700
2023	16,600
2024	16,500
2025	16,400
2026-2030	$ 78,700
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rates	2.40%	3.20%	4.20%
Expected long-term rates of return on plan assets	6.80%	7.00%	7.30%
Expected long-term rates of return on plan assets for next year (as a percent)	6.30%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rates	2.70%	2.40%
Highest yield U.S. dollar-denominated, AA-graded corporate bonds excluded from yield curve universe (as a percent)	10.00%
Lowest yield U.S. dollar-denominated, AA-graded corporate bonds excluded from yield curve universe (as a percent)	10.00%
International Plans | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 1,119,552	$ 984,665
Service cost	1,805	1,642	$ 1,308
Interest cost	12,652	17,599	22,148
Plan participants' contributions	15	18
Amendments	0	1,088
Actuarial loss	(58,567)	129,410
Settlements/curtailments	(269)	(256)
Benefits paid	(39,831)	(43,952)
Effect of foreign currency	(13,159)	29,379
Change in benefit obligation, Acquisition	0	41
Benefit obligation at end of year	1,022,198	1,119,552	984,665
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	957,177	860,321
Actual return on plan assets	40,382	95,132
Employer contributions	25,077	21,955
Plan participants' contributions	15	18
Settlements/curtailments	(269)	(256)
Benefits paid	(39,220)	(43,527)
Effect of foreign currency	(9,910)	23,534
Acquisitions/divestitures	0	0
Fair value of plan assets at end of year	973,252	957,177	$ 860,321
Funded status at end of year	(48,946)	(162,375)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent assets	2,046	0
Current liabilities	967	907
Noncurrent liabilities	50,025	161,468
Total accumulated other comprehensive loss before tax	410,114	487,682
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss	400,497	477,238
Prior service cost	9,617	10,444
Total accumulated other comprehensive loss before tax	410,114	$ 487,682
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Estimate of expected contributions in next fiscal year	24,700
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2021	40,900
2022	41,900
2023	43,100
2024	44,500
2025	45,900
2026-2030	$ 245,300
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rates	1.40%	2.10%	2.90%
Expected long-term rates of return on plan assets	4.70%	5.20%	5.50%
Expected long-term rates of return on plan assets for next year (as a percent)	4.40%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rates	1.90%	1.40%

Employee Benefit Plans (Detai_3

Employee Benefit Plans (Details 3) - Pension Plan $ in Thousands	12 Months Ended
	Dec. 31, 2022USD ($)	Dec. 31, 2021USD ($)marketshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)		4.70%
Expected long-term rates of return on plan assets		5.10%	5.60%	5.90%
International, Other Than United Kingdom [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Pension plan assets as a percentage of international plan assets		4.00%
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		$ 277,000	$ 296,700
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation		277,000	296,700
Accumulated benefit obligation		277,000	296,700
Fair value of plan assets		$ 232,900	$ 226,100
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Number of capital market results simulated in the model for expected return on plan assets | market		1,000
Period for which results of capital markets are simulated		20 years
Expected long-term rates of return on plan assets for next year (as a percent)		6.30%
Expected long-term rates of return on plan assets		6.80%	7.00%	7.30%
Number of shares of Company's common stock included in plan assets | shares		310,000	330,000
Fair values of plan assets		$ 232,947	$ 226,125	$ 226,268
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 232,947	226,125	226,268
Employer contributions		4,219	3,528
Fair value of plan assets at end of year		$ 232,947	$ 226,125	$ 226,268
U.S. Plans | Forecast
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets	6.30%
U.S. Plans | Domestic equity securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		22.80%	30.80%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 5,180	$ 5,934
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 5,180	5,934
Fair value of plan assets at end of year		$ 5,180	5,934
U.S. Plans | Domestic equity securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		18.00%
U.S. Plans | Domestic equity securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		28.00%
U.S. Plans | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 48,411	63,651
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	48,411	63,651
Fair value of plan assets at end of year		$ 48,411	$ 63,651
U.S. Plans | International equity securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		22.50%	26.50%
U.S. Plans | International equity securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		17.00%
U.S. Plans | International equity securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		27.00%
U.S. Plans | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 50,783	$ 59,933
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	50,783	59,933
Fair value of plan assets at end of year		$ 50,783	$ 59,933
U.S. Plans | Harsco common stock
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		2.20%	2.60%
U.S. Plans | Fixed income securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		45.90%	33.40%
U.S. Plans | Fixed income securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		41.00%
U.S. Plans | Fixed income securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		51.00%
U.S. Plans | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 105,114	$ 75,441
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	105,114	75,441
Fair value of plan assets at end of year		$ 105,114	$ 75,441
U.S. Plans | Other
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		8.80%	8.60%
U.S. Plans | Other | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		4.00%
U.S. Plans | Other | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		14.00%
U.S. Plans | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 9,371	$ 8,944
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	9,371	8,944
Fair value of plan assets at end of year		$ 9,371	$ 8,944
U.S. Plans | Cash and cash equivalents
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		0.00%	0.70%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 1,624	$ 1,691
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,624	1,691
Fair value of plan assets at end of year		$ 1,624	1,691
U.S. Plans | Cash and cash equivalents | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		5.00%
U.S. Plans | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 12,464	10,531
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	12,464	10,531
Fair value of plan assets at end of year		12,464	10,531
U.S. Plans | Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Value of shares of Company's common stock included in plan assets		5,200	5,900
U.S. Plans | Level 1
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		220,483	215,594
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	220,483	215,594
Fair value of plan assets at end of year		220,483	215,594
U.S. Plans | Level 1 | Domestic equity securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		5,180	5,934
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	5,180	5,934
Fair value of plan assets at end of year		5,180	5,934
U.S. Plans | Level 1 | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		48,411	63,651
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	48,411	63,651
Fair value of plan assets at end of year		48,411	63,651
U.S. Plans | Level 1 | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		50,783	59,933
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	50,783	59,933
Fair value of plan assets at end of year		50,783	59,933
U.S. Plans | Level 1 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		105,114	75,441
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	105,114	75,441
Fair value of plan assets at end of year		105,114	75,441
U.S. Plans | Level 1 | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		9,371	8,944
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	9,371	8,944
Fair value of plan assets at end of year		9,371	8,944
U.S. Plans | Level 1 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		1,624	1,691
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,624	1,691
Fair value of plan assets at end of year		1,624	1,691
U.S. Plans | Level 1 | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		12,464	10,531
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	12,464	10,531
Fair value of plan assets at end of year		12,464	10,531
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Domestic equity securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		12,464	10,531
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	12,464	10,531
Fair value of plan assets at end of year		12,464	10,531
International Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		1,016,100	1,113,400
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation		988,600	1,115,700
Accumulated benefit obligation		984,700	1,109,800
Fair value of plan assets		$ 939,300	$ 953,500
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)		4.40%
Expected long-term rates of return on plan assets		4.70%	5.20%	5.50%
Fair values of plan assets		$ 973,252	$ 957,177	$ 860,321
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	973,252	957,177	860,321
Employer contributions		25,077	21,955
Fair value of plan assets at end of year		$ 973,252	$ 957,177	$ 860,321
International Plans | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		27.90%	32.00%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		26.50%
International Plans | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 271,811	$ 306,959
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	271,811	306,959
Fair value of plan assets at end of year		$ 271,811	$ 306,959
International Plans | Fixed income securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		63.60%	49.50%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		65.50%
International Plans | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 613,243	$ 467,285
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	613,243	467,285
Fair value of plan assets at end of year		613,243	467,285
International Plans | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		5,684	6,282
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	5,684	6,282
Fair value of plan assets at end of year		$ 5,684	$ 6,282
International Plans | Other
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		7.80%	18.30%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		8.00%
International Plans | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		$ 75,651	$ 174,921
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	75,651	174,921
Fair value of plan assets at end of year		$ 75,651	$ 174,921
International Plans | Cash and cash equivalents
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31		0.70%	0.20%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)		0.00%
Fair values of plan assets		$ 6,863	$ 1,730
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	6,863	1,730
Fair value of plan assets at end of year		6,863	1,730
International Plans | Level 1
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		6,863	1,730
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	6,863	1,730
Fair value of plan assets at end of year		6,863	1,730
International Plans | Level 1 | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
International Plans | Level 1 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
International Plans | Level 1 | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
International Plans | Level 1 | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Fair value of plan assets at end of year		0	0
International Plans | Level 1 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		6,863	1,730
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	6,863	1,730
Fair value of plan assets at end of year		6,863	1,730
International Plans | Level 2
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		966,389	955,447
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	966,389	955,447
Fair value of plan assets at end of year		966,389	955,447
International Plans | Level 2 | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		271,811	306,959
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	271,811	306,959
Fair value of plan assets at end of year		271,811	306,959
International Plans | Level 2 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		613,243	467,285
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	613,243	467,285
Fair value of plan assets at end of year		613,243	467,285
International Plans | Level 2 | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		5,684	6,282
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	5,684	6,282
Fair value of plan assets at end of year		5,684	6,282
International Plans | Level 2 | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		75,651	174,921
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	75,651	174,921
Fair value of plan assets at end of year		75,651	174,921
International Plans | Level 2 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 0	0
Fair value of plan assets at end of year		$ 0	$ 0
United Kingdom
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)		4.30%	4.70%
Pension plan assets as a percentage of international plan assets		96.00%

Employee Benefit Plans (Detai_4

Employee Benefit Plans (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Contributions By The Company	$ 1.7	$ 1.6	$ 1.9

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income from continuing operations before income taxes and equity income
U.S.	$ (34,462)	$ (87,315)	$ (38,969)
International	71,968	33,095	70,034
Income (loss) from continuing operations before income taxes and equity income	37,506	(54,220)	31,065
Currently payable:
U.S. federal	0	(12,116)	902
U.S. state	507	468	220
International	22,295	16,518	21,132
Total income taxes currently payable	22,802	4,870	22,254
Deferred U.S. federal	(4,594)	(10,558)	(9,367)
Deferred U.S. state	(18)	(3,078)	(2,575)
Deferred international	(9,101)	93	2,416
Total income tax expense from continuing operations	9,089	(8,673)	12,728
Cash payments for income taxes, including taxes on gain or loss from discontinued business	$ 21,700	$ 34,900	$ 115,600

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Foreign earnings before tax	$ 71,968	$ 33,095	$ 70,034
Differences on international earnings and remittances	4,500	7,900
Income Tax Expense (Benefit)	9,089	(8,673)	12,728
Total international income tax expense	22,295	16,518	21,132
Operating loss carryforwards	65,935	66,703
Valuation Allowance	92,385	108,563
Interest and penalties recognized	400	200	300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	1,700	1,400	$ 1,200
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	400
Current Foreign Tax Expense (Benefit)	13,200	16,600
International operations
Income Tax Disclosure [Line Items]
Operating loss carryforwards	40,900
Operating loss carryforwards not subject to expiration	32,000
Operating losses subject to expiration	8,900
U.S. state
Income Tax Disclosure [Line Items]
Operating loss carryforwards	16,000
United States
Income Tax Disclosure [Line Items]
Differences on international earnings and remittances	100	$ 100
Brazil | Harsco Environmental
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)	$ 6,800

Income Taxes (Details 3)

Income Taxes (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. federal income tax expense (benefit), at statutory tax rate of 21%	$ 7,877	$ (11,386)	$ 6,523
U.S. state income taxes, net of federal income tax benefit	(310)	(2,015)	(1,290)
U.S. other domestic deductions and credits	(415)	(1,312)	(596)
Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential and Repatriation of Foreign Earnings	(4,488)	(7,872)	(7,536)
Uncertain tax position contingencies and settlements	783	289	310
Changes in realization on beginning of the year deferred tax assets	(5,035)	(1,501)	2,343
U.S. non-deductible expenses	936	2,300	2,461
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Amount	0	0	1,644
Effective Income Tax Rate Reconciliation, Net Operating Loss Carryback, Amount		(2,696)	0
State deferred tax rate changes	592	(40)	(3,354)
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	173	(184)	(2,817)
Other, net	0	0	(32)
Total income tax expense from continuing operations	$ 9,089	$ (8,673)	$ 12,728
Annual effective income tax rate	24.20%	16.00%	41.00%
International	$ 71,968	$ 33,095	$ 70,034
Income Tax Expense (Benefit)	9,089	(8,673)	12,728
Current Foreign Tax Expense (Benefit)	13,200	16,600
Differences on international earnings and remittances	4,500	7,900
U.S.	(34,462)	(87,315)	$ (38,969)
Income Tax Expense (Benefit), Increase (Decrease) From Prior Year	$ 4,100	$ 25,300

Income Taxes (Details 4)

Income Taxes (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
U.S.	$ 34,462	$ 87,315	$ 38,969
Interest and penalties recognized	400	200	$ 300
Asset
Depreciation and amortization	0	0
Operating lease liabilities	25,431	22,868
Expense accruals	24,949	22,136
Inventories	3,400	2,721
Provision for receivables	5,504	4,903
Operating loss carryforwards	65,935	66,703
Tax credit carryforwards	18,608	15,630
Pensions	23,298	49,740
Currency adjustments	5,075	4,829
Deferred financing costs	359
Section 163(j) disallowed interest expense	4,843
Post-retirement benefits	335	340
Stock based compensation	7,396	6,696
Other	1,470	1,954
Subtotal	186,603	198,520
Valuation allowance	(92,385)	(108,563)
Total deferred income taxes	94,218	89,957
Liability
Depreciation and amortization	80,278	87,681
Right-of-use assets	25,759	23,406
Deferred revenue	4,124	4,425
Deferred financing costs		269
Deferred Tax Liabilities, Other	0	0
Total deferred income taxes	110,161	115,781
Deferred Tax Assets, Net, Classification [Abstract]
Deferred income tax assets	17,883	10,368
Deferred tax liabilities	33,826	$ 36,192
Valuation Allowance, Deferred Tax Asset, Decrease From Pension Adjustment	19,300
Valuation Allowance, Deferred Tax Asset, Decrease From Asset Valuation	6,800
Valuation Allowance, Deferred Tax Asset, Increase From Tax Rate Adjustment	14,400
Valuation Allowance, Deferred Tax Asset, Reduction Related to Disallowed Interest Expense	4,800
Foreign Currency Translation Adjustment, Valuation Allowance Reduction, Reduction to Deferred Tax Assets	3,500
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards not subject to expiration	7,200
Asset
Operating loss carryforwards	9,000
Domestic Tax Authority [Member] | Tax Years 2021 Through 2040 [Member]
Asset
Operating loss carryforwards	1,800
International operations
Operating Loss Carryforwards [Line Items]
Operating losses subject to expiration	8,900
Operating loss carryforwards not subject to expiration	32,000
Asset
Operating loss carryforwards	40,900
U.S. state
Asset
Operating loss carryforwards	16,000
U.S. state | Tax Years 2021 Through 2025 [Member]
Asset
Operating loss carryforwards	3,600
U.S. state | Tax Years 2026 Through 2030 [Member]
Asset
Operating loss carryforwards	3,200
U.S. state | Tax Years 2031 Through 2035 [Member]
Asset
Operating loss carryforwards	4,700
U.S. state | Tax Years 2036 Through 2040 [Member]
Asset
Operating loss carryforwards	$ 4,500

Income Taxes (Details 5)

Income Taxes (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at the beginning of the period	$ 2,896	$ 3,129	$ 2,422
Additions for tax positions related to the current year (includes currency translation adjustment)	316	596	414
Additions for tax positions related to prior years (includes currency translation adjustment)	500		681
Statutes of limitations expirations	(585)	(58)	(326)
Other reductions for tax positions related to prior years		771
Settlements			(62)
Balance at the end of the period	3,127	2,896	3,129
Reconciliation of Deferred Income Tax Benefits [Roll Forward]
Balance at beginning of period	(22)	(22)	(26)
Additions for tax positions related to the current year (includes currency translation adjustment)	(1)	(2)	(7)
Additions for tax positions related to prior years (includes currency translation adjustment)	0
Other reductions for tax positions related to prior years		0
Statutes of limitation expirations	1	2	2
Settlements			9
Balance at the end of the period	(22)	(22)	(22)
Reconciliation of Net Unrecognized Tax Benefits [Roll Forward]
Balance at the beginning of the period	2,874	3,107	2,396
Additions for tax positions related to the current year (includes currency translation adjustment)	315	594	407
Additions for tax positions related to prior years (includes currency translation adjustment)	500		681
Other reductions for tax positions related to prior years		(771)
Statutes of limitation expirations	(584)	(56)	(324)
Settlements			(53)
Balance at the end of the period	$ 3,105	$ 2,874	$ 3,107

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Loss Contingencies by Contingency (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Current Portion of Environmental Liabilities	$ 7,338,000	$ 6,862,000
Total environmental liabilities	35,773,000	36,286,000
Accrued Environmental Loss Contingencies, Noncurrent	$ 28,435,000	$ 29,424,000

Commitments and Contingencies (

Commitments and Contingencies (Details)	Dec. 06, 2018USD ($)	Jun. 04, 2018USD ($)	Aug. 31, 2005USD ($)	Dec. 31, 2021USD ($)claimcasedefendant	Nov. 23, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 30, 2020USD ($)	Nov. 01, 2019USD ($)	Nov. 01, 2019BRL (R$)	Mar. 19, 2019USD ($)	Mar. 19, 2019BRL (R$)
Commitments and Contingencies
Accrual for Environmental Loss Contingencies				$ 7,500,000
Penalties per day								$ 5,000	R$ 25000	$ 1,000	R$ 5000
Penalties								2,000,000	10,000,000
Proposed Civil Penalty					$ 390,092
Loss contingency, Brazilian labor claims
Commitments and Contingencies
Liabilities for asserted and unasserted claims				$ 3,200,000		$ 4,300,000
Other
Commitments and Contingencies
Number of pending claims | claim				17,240
Loss provision				$ 0
Loss Contingency, Number of Defendants | defendant				90
Loss Contingency, Claims Dismissed, Number | case				28,360
Other | Minimum
Commitments and Contingencies
Loss Contingency, Damages Sought, Value				$ 20,000,000
Other | Maximum
Commitments and Contingencies
Loss Contingency, Damages Sought, Value				$ 25,000,000
Pending Litigation, Active Or In Extremis Docket | Other
Commitments and Contingencies
Number of pending claims | claim				60
Sao Paulo State Revenue Authority | Value-Added Tax Assessments January 2004 To May 2005
Commitments and Contingencies
Loss Contingency, Damages Sought, Principal Amount		$ 1,100,000		$ 1,100,000
Estimated claims or assessment, additional amount		$ 7,000,000		15,400,000
Sao Paulo State Revenue Authority | Value-Added Tax Assessments January 2002 To December 2003
Commitments and Contingencies
Loss Contingency, Damages Sought, Principal Amount			$ 1,100,000
Estimated claims or assessment, additional amount	$ 5,000,000		3,400,000
Loss Contingency, Damages Sought, Value	$ 800,000		$ 4,500,000
Loss provision				$ 0
New York County as managed by the New York Supreme Court | Other
Commitments and Contingencies
Number of pending claims | case				16,610
New York County as managed by the New York Supreme Court | Pending And Future Litigation, Deferred Or Inactive Docket | Other
Commitments and Contingencies
Number of pending claims | claim				16,550
New York State Supreme Court, Counties Excluding New York County [Member] | Other
Commitments and Contingencies
Number of pending claims | case				120
Courts Located In States Other Than New York | Other
Commitments and Contingencies
Number of pending claims | case				510
Brazil
Commitments and Contingencies
Loss Contingencies, Unpaid Service Taxes							$ 1,900,000
Loss Contingencies, Overall Liability				$ 3,000,000
CSN [Member]
Commitments and Contingencies
Penalties per day								$ 20,000	R$ 100000	$ 4,000	R$ 20000

Capital Stock (Details)

Capital Stock (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Common stock authorized (in shares)	150,000,000
Preferred stock authorized (in shares)	4,000,000
Common stock, par value (usd per share)	$ 1.25	$ 1.25
Preferred stock authorized, par value (in dollars per share)	$ 1.25
Preferred stock, shares issued (in shares)	0

Capital Stock (Details 2)

Capital Stock (Details 2) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Common Stock
Common Stock, Shares, Issued	115,430,042	114,720,347	113,473,951
Treasury Stock, Shares, Beginning Balance	36,505,672	36,205,589	33,928,928
Common Stock, Shares, Outstanding, Beginning Balance	78,924,370	78,514,758	79,545,023
Vested Restricted Stock Units (in shares)	305,535	229,413	321,965
Stock Issued During Period, Shares, Other	124,077	471,412	908,566
Stock issued during period, stock appreciation rights (in shares)	46,739	8,870	15,865
Treasury shares purchased			1,766,826
Shares outstanding at the end of the period	115,906,393	115,430,042	114,720,347
Treasury Stock, Shares	36,690,847	36,505,672	36,205,589
Common Stock, Shares, Outstanding	79,215,546	78,924,370	78,514,758
Treasury Stock
Common Stock
Vested Restricted Stock Units (in shares)	112,275	91,188	125,863
Stock Issued During Period, Shares, Other	54,950	206,261	379,353
Stock issued during period, stock appreciation rights (in shares)	17,950	2,634	4,619
Treasury shares purchased			1,766,826
Outstanding Shares
Common Stock
Vested Restricted Stock Units (in shares)	193,260	138,225	196,102
Stock Issued During Period, Shares, Other	69,127	265,151	529,213
Stock issued during period, stock appreciation rights (in shares)	28,789	6,236	11,246
Treasury shares purchased			1,766,826

Capital Stock - Reconciliation

Capital Stock - Reconciliation of the average shares of common stock used to compute basic earnings per common share to the shares used to compute diluted earnings per common share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of the average shares of common stock used to compute basic earnings per common share to the shares used to compute diluted earnings per common share
Income (loss) from continuing operations attributable to Harsco Corporation common stockholders (in dollars)									$ 22,137	$ (49,727)	$ 10,311
Weighted average shares of common stock outstanding									79,234	78,939	79,632
Dilutive effect of stock-based compensation (in shares)									1,055	0	1,743
Weighted-average shares outstanding—diluted (in shares)									80,289	78,939	81,375
Basic (in dollars per share)	$ 0.13	$ 0.06	$ 0.11	$ (0.02)	$ (0.09)	$ (0.12)	$ (0.25)	$ (0.17)	$ 0.28	$ (0.63)	$ 0.13
Diluted (in dollars per share)	$ 0.13	$ 0.06	$ 0.11	$ (0.02)	$ (0.09)	$ (0.12)	$ (0.25)	$ (0.17)	$ 0.28	$ (0.63)	$ 0.13

Capital Stock (Details 3)

Capital Stock (Details 3) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted stock units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	0	714	0
Stock Appreciation Rights (SARs)
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	826	2,474	491
Performance Shares [Member]
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	865	887	124

Stock-Based Compensation (Restr

Stock-Based Compensation (Restricted Stock) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Additional disclosures
Excess tax benefits from stock-based compensation		$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	366,349
Granted (in dollars per share)	$ 18.81
Recognized stock-based compensation expense	$ 4,819,000	$ 3,665,000	$ 4,116,000
Restricted stock unit activity
Nonvested at the beginning of the period (in shares)	686,287
Granted (in shares)	366,349
Vested (in shares)	(307,543)
Forfeited (in shares)	(32,249)
Nonvested at the end of the period (in shares)	712,844	686,287
Weighted Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)	$ 11.84
Granted (in dollars per share)	18.81
Vested (in dollars per share)	13.33
Forfeited (in dollars per share)	14.16
Nonvested at the end of the period (in dollars per share)	$ 14.68	$ 11.84
Additional disclosures
Unrecognized stock-based compensation expense	$ 6,000,000
Unrecognized stock-based compensation expense, period of recognition	1 year 10 months 24 days
Fair value of RSU, vested in period	$ 4,100,000	$ 4,300,000	$ 4,700,000
Restricted stock units | Officers And Key Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Restricted stock units | Non-employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	1 year
2013 Equity and Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for issuance	9,900,000
Number of shares available for grant	2,400,000
2013 Equity and Incentive Compensation Plan | Equity Awards, Other Than Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for issuance	6,500,000
Number of shares available for grant	1,800,000
1995 Non-Employee Directors' Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for issuance	800,000
Number of shares available for grant	430,000
1995 Non-Employee Directors' Stock Plan | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	23,224	34,986	14,211	43,821
Granted (in dollars per share)	$ 21.53	$ 10.29	$ 25.33	$ 20.54
Restricted stock unit activity
Granted (in shares)	23,224	34,986	14,211	43,821
Weighted Average Grant-Date Fair Value
Granted (in dollars per share)	$ 21.53	$ 10.29	$ 25.33	$ 20.54
1995 Non-Employee Directors' Stock Plan | Restricted stock units | 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 0	$ 0	$ 280,000
1995 Non-Employee Directors' Stock Plan | Restricted stock units | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	0	120,000	240,000
1995 Non-Employee Directors' Stock Plan | Restricted stock units | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	120,000	240,000	0
1995 Non-Employee Directors' Stock Plan | Restricted stock units | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 333,000	$ 0	$ 0
1995 Executive Incentive Compensation Plan | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	343,125	522,087	270,864	242,791	286,251	536,773
Granted (in dollars per share)	$ 18.62	$ 8.22	$ 22.25	$ 19.93	$ 13.70	$ 7.09
Restricted stock unit activity
Granted (in shares)	343,125	522,087	270,864	242,791	286,251	536,773
Weighted Average Grant-Date Fair Value
Granted (in dollars per share)	$ 18.62	$ 8.22	$ 22.25	$ 19.93	$ 13.70	$ 7.09
1995 Executive Incentive Compensation Plan | Restricted stock units | 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 0	$ 0	$ 245,000
1995 Executive Incentive Compensation Plan | Restricted stock units | 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	0	85,000	763,000
1995 Executive Incentive Compensation Plan | Restricted stock units | 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	142,000	706,000	1,064,000
1995 Executive Incentive Compensation Plan | Restricted stock units | 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	1,239,000	1,270,000	1,524,000
1995 Executive Incentive Compensation Plan | Restricted stock units | 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	1,093,000	1,244,000	0
1995 Executive Incentive Compensation Plan | Restricted stock units | 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized stock-based compensation expense	$ 1,892,000	$ 0	$ 0

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Appreciation Rights) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended					12 Months Ended
	Mar. 31, 2021	Oct. 31, 2020	Mar. 31, 2020	Jul. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 31, 2019
Number of Shares
Stock appreciation rights exercised (in shares)						(28,789)	(6,236)	(11,246)
Weighted Average Exercise Price
Options vested, outstanding (in shares)						1,729,175
Options non-vested (in shares)						664,880
Weighted Average Exercise Price Per Share (in dollars per share)						$ 14.75
Weighted-Average Remaining Contractual Life in Years						5 years 8 months 23 days
Number of exercisable options (in shares)						1,729,175
Weighted average exercise price per share (in dollars per share)						$ 15.21
$7.00 - $14.89
Weighted Average Exercise Price
Options vested, outstanding (in shares)						807,168
Options non-vested (in shares)						443,256
Weighted Average Exercise Price Per Share (in dollars per share)						$ 9.87
Weighted-Average Remaining Contractual Life in Years						6 years 6 months 10 days
Number of exercisable options (in shares)						807,168
Weighted average exercise price per share (in dollars per share)						$ 9.48
$16.53 - $22.70
Weighted Average Exercise Price
Options vested, outstanding (in shares)						727,909
Options non-vested (in shares)						221,624
Weighted Average Exercise Price Per Share (in dollars per share)						$ 19.12
Weighted-Average Remaining Contractual Life in Years						5 years 3 months 21 days
Number of exercisable options (in shares)						727,909
Weighted average exercise price per share (in dollars per share)						$ 19.01
$23.25 - $26.92
Weighted Average Exercise Price
Options vested, outstanding (in shares)						194,098
Options non-vested (in shares)						0
Weighted Average Exercise Price Per Share (in dollars per share)						$ 24.80
Weighted-Average Remaining Contractual Life in Years						2 years 7 months 9 days
Number of exercisable options (in shares)						194,098
Weighted average exercise price per share (in dollars per share)						$ 24.80
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)						3 years
Expiration period (in years)						10 years
Fair value assumptions
Risk-free interest rate (as a percent)	0.91%	0.44%	0.76%	1.84%	2.52%
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%	0.00%
Expected life	6 years	6 years	6 years	6 years	6 years
Volatility (as a percent)	61.90%	60.30%	45.20%	47.10%	46.20%
SAR grant price (usd per share)	$ 18.58	$ 14.89	$ 10.29		$ 22.51				$ 27.39
Number of Shares
Outstanding at beginning of period (in shares)						2,401,131
Granted (in shares)						184,641
Stock appreciation rights exercised (in shares)						(107,413)
Forfeited (in shares)						(84,304)
Outstanding at end of period (in shares)						2,394,055	2,401,131
Weighted Average Exercise Price
Outstanding at beginning of period (usd per share)						$ 14.37
Granted (usd per share)						18.58
Exercised (in dollars per share)						10.81
Forfeited/expired (usd per share)						17.31
Outstanding at end of period						$ 14.75	$ 14.37
Outstanding - Aggregate Intrinsic Value						$ 8.6	$ 11.7
Total intrinsic value of SARs						0.6	0.5	$ 0.3
Recognized stock-based compensation expense						1.8	$ 1.7	$ 1.8
Unrecognized stock-based compensation expense						$ 2.2
Unrecognized stock-based compensation expense, period of recognition						1 year 9 months 18 days
Unvested activity
Nonvested at the beginning of the period (in shares)						877,947
Granted (in shares)						184,641
Vested (in shares)						(348,340)
Forfeited						(49,368)
Nonvested at the end of the period (in shares)						664,880	877,947
Weighted Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)						$ 4.50
Granted (in dollars per share)	$ 10.48	$ 8.12	$ 3.03	$ 12.80	$ 10.62	10.48
Vested (in dollars per share)						5.33
Forfeited (in dollars per share)						5.77
Nonvested at the end of the period (in dollars per share)						5.63	$ 4.50
Stock Appreciation Rights (SARs) | $7.00 - $14.89
Weighted Average Exercise Price
Range of Exercisable Prices, low end of range (in dollars per share)						7
Range of Exercisable Prices, high end of range (in dollars per share)						14.89
Stock Appreciation Rights (SARs) | $16.53 - $22.70
Weighted Average Exercise Price
Range of Exercisable Prices, low end of range (in dollars per share)						16.53
Range of Exercisable Prices, high end of range (in dollars per share)						22.70
Stock Appreciation Rights (SARs) | $23.25 - $26.92
Weighted Average Exercise Price
Range of Exercisable Prices, low end of range (in dollars per share)						23.25
Range of Exercisable Prices, high end of range (in dollars per share)						$ 26.92
2013 Equity and Incentive Compensation Plan | Stock Appreciation Rights (SARs)
Unvested activity
Granted (in shares)	184,641	20,526	785,152	13,244	216,100

Stock-Based Compensation (Perfo

Stock-Based Compensation (Performance Stock Units) (Details) - Performance Stock Units - USD ($) $ / shares in Units, $ in Millions	1 Months Ended						12 Months Ended
	Mar. 31, 2021	Oct. 31, 2020	Mar. 31, 2020	Aug. 31, 2019	Jul. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period							3 years
Fair value assumptions
Risk-free interest rate (as a percent)	0.25%	0.17%	0.56%	1.57%	1.75%	2.48%
Dividend yield (as a percent)	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Expected Life (Years)	2 years 9 months 29 days	2 years 2 months 12 days	2 years 9 months 21 days	2 years 4 months 28 days	2 years 6 months	2 years 9 months 25 days
Volatility	50.70%	53.70%	36.00%	34.90%	34.30%	33.80%
Fair value of award (in dollars per share)	$ 25.38	$ 17.01	$ 4.40	$ 23.38	$ 40.07	$ 29.04	$ 25.38
Recognized stock-based compensation expense							$ 5.1	$ 3.2	$ 4.8
Unrecognized stock-based compensation expense							$ 5.6
Unrecognized stock-based compensation expense, period of recognition							1 year 10 months 24 days
Unvested activity
Nonvested at the beginning of the period (in shares)							696,318
Granted (in shares)	316,959	11,194	513,995	38,006	6,189	233,112	316,959
Forfeited (in shares)							(44,839)
Vested (in shares)							(214,645)
Nonvested at the end of the period (in shares)							753,793	696,318
Weighted Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)							$ 11.85
Granted (in dollars per share)	$ 25.38	$ 17.01	$ 4.40	$ 23.38	$ 40.07	$ 29.04	25.38
Forfeited (in dollars per share)							15.47
Vested (in dollars per share)							26.84
Nonvested at the end of the period (in dollars per share)							$ 13.05	$ 11.85
Shares expected to be issued (in shares)							0
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout of PSUs (percent of initial grant)							0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout of PSUs (percent of initial grant)							200.00%

Financial Instruments - Narrati

Financial Instruments - Narrative (Details)	1 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)	Dec. 31, 2022	Dec. 31, 2021USD ($)country	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Guarantor Obligations [Line Items]
Derivatives liability resulted from netting arrangement			$ 900,000
Pre-tax gains (losses)			2,700,000	$ 400,000	$ 7,700,000
Repayments of Long-term Lines of Credit	$ 2,800,000
Fair value of long-term debt			1,394,200,000	1,324,900,000
Long-term Debt, Gross			$ 1,387,889,000	1,300,532,000
LIBOR | Fixed-Rate Term Loan | Term Loan
Guarantor Obligations [Line Items]
Basis spread on variable rate			2.71%
Forecast | LIBOR | Fixed-Rate Term Loan | Term Loan
Guarantor Obligations [Line Items]
Basis spread on variable rate		3.12%
Foreign currency exchange forward contracts
Guarantor Obligations [Line Items]
Notional amounts			$ 425,800,000	460,500,000
Minimum
Guarantor Obligations [Line Items]
Number of countries in which entity has currency exposures | country			30
Stand by letters of credit, bonds and bank guarantees
Guarantor Obligations [Line Items]
Contingent liability outstanding			$ 519,400,000	410,600,000	281,800,000
Guarantee term			2 years
Stand by letters of credit, bonds and bank guarantees | Minimum
Guarantor Obligations [Line Items]
Guarantee term			1 year
Fees paid to various banks and insurance companies on face amount of instruments (as a percent)			0.40%
Stand by letters of credit, bonds and bank guarantees | Maximum
Guarantor Obligations [Line Items]
Guarantee term			5 years
Fees paid to various banks and insurance companies on face amount of instruments (as a percent)			3.80%
Indemnification Agreement
Guarantor Obligations [Line Items]
Recognition of potential future payment in the consolidated financial statements			$ 0
Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member] | Interest rate swaps
Guarantor Obligations [Line Items]
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ (2,700,000)		$ 0	$ (2,700,000)	$ (2,741,000)

Financial Instruments - Fair Va

Financial Instruments - Fair Value of Outstanding Derivative Contracts Recorded as Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	$ 2,124	$ 3,677
Liability derivatives (Level 2)	7,622	12,725
Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	2,124	3,677
Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	3,465	5,048
Interest rate swaps | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	4,157	3,959
Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)		3,718
Fair Value of Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	719	900
Liability derivatives (Level 2)	4,717	8,627
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	719	900
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	560	950
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	4,157	3,959
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)		3,718
Fair Value of Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	1,405	2,777
Liability derivatives (Level 2)	2,905	4,098
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	1,405	2,777
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	2,905	4,098
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	$ 0	0
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)		$ 0

Financial Instruments - Effect

Financial Instruments - Effect of Derivative Instruments on the Consolidated Statements of Operations and the Consolidated Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Product revenues		$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Interest expense										(63,235)	(58,196)	(34,024)
Income (loss) from discontinued businesses										(25,863)	20,350	52,937
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										3,345	2,578	(2,934)
Foreign currency exchange forward contracts | Product revenues / Cost of services and products sold
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										0	0	(44)
Derivative Not Designated as Hedging Instruments
Amount of Gain (Loss) Recognized in Income on Derivative for the Twelve Months Ended December 31										10,761	(9,052)	6,807
Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										(3,474)	(2,589)	520
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net										89		0
Interest rate swaps | Cost of Goods and Service Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax												0
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net												0
Interest rate swaps | Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										0	0	(2,741)
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ (2,700)									0	(2,700)	(2,741)
Cross-currency interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										0	(1,015)	(1,219)
Cross-currency interest rate swaps | Cost of Goods and Service Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax												0
Cross-currency interest rate swaps | Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax											0	0
Foreign Exchange Contract [Member] | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										0	0	0
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease) Based On Amortization Approach, before Adjustments and Tax										0	0
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax										0
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing											0	0
Foreign Exchange Contract [Member] | Cost of Goods and Service Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax												(44)
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing												0
Foreign Exchange Contract [Member] | Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax										(129)	1,026	550
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease) Based On Amortization Approach, before Adjustments and Tax										(2)	31
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax										62
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing											197	509
Product
Derivative Instruments, Gain (Loss) [Line Items]
Product revenues										147,503	133,385	145,996
Cost of services and products sold										121,483	101,988	108,054
Services
Derivative Instruments, Gain (Loss) [Line Items]
Product revenues										1,700,896	1,400,648	1,058,373
Cost of services and products sold										$ 1,369,073	$ 1,140,303	$ 822,043

Financial Instruments - Effec_2

Financial Instruments - Effect of Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 267	$ (4,780)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			$ (9,478)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(3,345)	(2,578)	2,934
Foreign currency exchange forward contracts
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			(41)
Foreign Exchange Forward Two [Member]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	309	(930)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			(1,186)
Interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			0
Interest Rate Swap Two [Member]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	(42)	(3,889)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			(8,209)
Cross-currency interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0	39
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax			(42)
Product revenues / Cost of services and products sold | Foreign currency exchange forward contracts
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	0	44
Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	0	2,741
Discontinued Operation, Gain (Loss) From Disposal Of Discontinued Operation [Member] | Cross-currency interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax		0	0
Interest expense | Interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	3,474	2,589	(520)
Interest expense | Cross-currency interest rate swaps
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	1,015	1,219
Discontinued Operations, Held-for-sale or Disposed of by Sale | Foreign currency exchange forward contracts
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	$ 129	$ 1,026	$ (550)

Information by Segment and Ge_3

Information by Segment and Geographic Area (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)Customersegment	Dec. 31, 2020USD ($)Customer	Dec. 31, 2019USD ($)Customer
Revenue, Major Customer [Line Items]
Revenues	$ 1,848,399	$ 1,534,033	$ 1,204,369
Number of reportable segments | segment	2
Number of major customers | Customer	1
Harsco Environmental
Revenue, Major Customer [Line Items]
Number of major customers | Customer	1	1	1
Clean Earth
Revenue, Major Customer [Line Items]
Number of major customers | Customer	1	0
All Other
Revenue, Major Customer [Line Items]
Revenues	$ 722,181	$ 586,909	$ 656,753
U.S. Plans
Revenue, Major Customer [Line Items]
Revenues	1,008,689	830,699	420,956
United Kingdom
Revenue, Major Customer [Line Items]
Revenues	$ 117,529	$ 116,425	$ 126,660

Information by Segment and Ge_4

Information by Segment and Geographic Area (Details 2) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 653,913	$ 630,354
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	267,174	253,994
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	108,496	109,617
All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 278,243	$ 266,743

Information by Segment and Ge_5

Information by Segment and Geographic Area (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 1,848,399	$ 1,534,033	$ 1,204,369
Operating income from continuing operations	88,376	(3,306)	76,403
Total assets	3,053,908	2,993,287	2,367,467
Depreciation	131,449	125,765	119,803
Depreciation Excluding Industrial Segment	127,402	120,443	112,509
Amortization	35,224	33,937	18,592
Amortization Excluding Deferred Financing Costs	34,942	33,600	17,709
Capital Expenditures	156,920	112,156	161,326
Interest income	2,231	2,129	1,946
Interest expense	(63,235)	(58,196)	(34,024)
Defined benefit pension income (expense)	15,640	7,073	(5,556)
Loss on early extinguishment of debt	(5,506)	(1,920)	(7,704)
Income (loss) from continuing operations before income taxes and equity income	37,506	(54,220)	31,065
Clean Earth
Segment Reporting Information [Line Items]
Operating income from continuing operations	25,639	16,096	20,009
Total assets	1,278,472	1,279,387	745,410
Depreciation	19,672	17,450	4,932
Amortization	24,180	22,814	7,923
Capital Expenditures	18,403	12,612	5,870
Operating segments
Segment Reporting Information [Line Items]
Operating income from continuing operations	129,041	75,102	132,307
Operating segments | Harsco Environmental
Segment Reporting Information [Line Items]
Revenues	1,068,083	914,445	1,034,847
Operating income from continuing operations	103,402	59,006	112,298
Total assets	1,386,087	1,322,731	1,296,061
Depreciation	105,830	100,971	104,840
Amortization	8,052	7,825	7,286
Capital Expenditures	137,228	99,056	153,694
Operating segments | Clean Earth
Segment Reporting Information [Line Items]
Revenues	780,316	619,588	169,522
Operating segments | Harsco Industrial
Segment Reporting Information [Line Items]
Total assets	333,263	316,984	297,541
Corporate
Segment Reporting Information [Line Items]
Operating income from continuing operations	(40,665)	(78,408)	(55,904)
Total assets	56,086	74,185	28,455
Depreciation	1,900	2,022	2,737
Amortization	2,710	2,961	2,500
Capital Expenditures	$ 1,289	$ 488	$ 1,762

Revenue Recognition - Summary o

Revenue Recognition - Summary of Revenues by Primary Geographical Markets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues									920,579	781,060	888,851
Applied Products [Member]
Disaggregation of Revenue [Line Items]
Total revenues									132,389	120,432	127,874
Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues									15,114	12,953	18,122
Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									780,317	619,588	169,522
North America
Disaggregation of Revenue [Line Items]
Total revenues									1,061,441	869,492	463,889
Western Europe
Disaggregation of Revenue [Line Items]
Total revenues									442,286	377,066	386,593
Latin America
Disaggregation of Revenue [Line Items]
Total revenues									132,349	119,457	146,040
Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues									110,790	87,608	128,949
Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues									81,337	63,427	60,402
Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues									20,196	16,983	18,496
Harsco Environmental | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues									1,068,082	914,445	1,034,847
Harsco Environmental | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues									920,579	781,060	888,851
Harsco Environmental | Operating segments | Applied Products [Member]
Disaggregation of Revenue [Line Items]
Total revenues									132,389	120,432	127,874
Harsco Environmental | Operating segments | Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues									15,114	12,953	18,122
Harsco Environmental | Operating segments | Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Harsco Environmental | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues									281,124	249,904	294,367
Harsco Environmental | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues									442,286	377,066	386,593
Harsco Environmental | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues									132,349	119,457	146,040
Harsco Environmental | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues									110,790	87,608	128,949
Harsco Environmental | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues									81,337	63,427	60,402
Harsco Environmental | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues									20,196	16,983	18,496
Clean Earth | Operating segments
Disaggregation of Revenue [Line Items]
Total revenues									780,317	619,588	169,522
Clean Earth | Operating segments | Environmental services related to resource recovery for metals manufacturing; and related logistical services
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Applied Products [Member]
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Aluminum Dross and Scrap Processing Systems [Member]
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Waste Processing and Reuse Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									780,317	619,588	169,522
Clean Earth | Operating segments | North America
Disaggregation of Revenue [Line Items]
Total revenues									780,317	619,588	169,522
Clean Earth | Operating segments | Western Europe
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Latin America
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Asia-Pacific
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Clean Earth | Operating segments | Eastern Europe
Disaggregation of Revenue [Line Items]
Total revenues									$ 0	$ 0	$ 0

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Total contract assets	$ 3.1	$ 2.5
Revenue recognized in excess of amounts reclassified to trade accounts receivable, net	4.1	$ 2.7
Contract with Customer, Liability, Revenue Recognized	$ 15

Revenue Recognition - Performan

Revenue Recognition - Performance Obligation Period Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Harsco Environmental
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 82.8
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Remaining performance obligation	20.1
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Remaining performance obligation	19.7
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Remaining performance obligation	19
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Remaining performance obligation	$ 16.6
Harsco Environmental | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period		1 year
Harsco Rail | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance period

Other Expenses (Details)

Other Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Employee termination benefit costs	$ 4,766	$ 10,249	$ 4,226
Costs to exit activities	663	533	1,166
Impaired asset write-downs	1,005	776	632
Contingent Consideration Adjustments	0	(2,386)	7,681
Other expense	(1,254)	(149)	(234)
Total	(3,722)	10,072	(8,194)
Corporate
Segment Reporting Information [Line Items]
Employee termination benefit costs	1,481	27	1,012
Costs to exit activities	0	29	196
Contingent Consideration Adjustments	0	(2,274)	0
Clean Earth
Segment Reporting Information [Line Items]
Employee termination benefit costs	433	833	1,960
Costs to exit activities	23	0	0
Impaired asset write-downs	63	0	0
Contingent Consideration Adjustments	0	(112)	(825)
Harsco Environmental
Segment Reporting Information [Line Items]
Net gains	(8,902)	(3,723)	(6,303)
Employee termination benefit costs	2,852	9,389	1,254
Costs to exit activities	640	504	970
Impaired asset write-downs	942	776	632
Contingent Consideration Adjustments	$ 0	$ 0	$ 8,506

Components of Accumulated Oth_3

Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	$ 713,399	$ 789,659	$ 313,376
OCI before reclassifications	58,995	(92,545)
Amounts reclassified from AOCI, net of tax	25,110	37,238
Total OCI	84,105	(55,307)	(58)
Plus: OCI attributable to noncontrolling interests	1,497	(2,812)
OCI attributable to Harsco Corporation	85,602	(58,119)
Balances	805,770	713,399	789,659
Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances			0
Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(587,622)
Balances			(587,622)
Cumulative Foreign Exchange Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(125,392)
OCI before reclassifications	(10,994)	7,854
Amounts reclassified from AOCI, net of tax		12,906
Total OCI	(10,994)	20,760
Plus: OCI attributable to noncontrolling interests	1,497	(2,812)
OCI attributable to Harsco Corporation	(9,497)	17,948
Balances	(134,889)	(125,392)
Cumulative Foreign Exchange Translation Adjustments | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(143,340)
Balances			(143,340)
Effective Portion of Derivatives Designated as Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(5,840)
OCI before reclassifications	441	(3,709)
Amounts reclassified from AOCI, net of tax	2,375	1,586
Total OCI	2,816	(2,123)
Plus: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	2,816	(2,123)
Balances	(3,024)	(5,840)
Effective Portion of Derivatives Designated as Hedging Instruments | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(3,717)
Balances			(3,717)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(514,500)
OCI before reclassifications	69,517	(96,684)
Amounts reclassified from AOCI, net of tax	22,735	22,746
Total OCI	92,252	(73,938)
Plus: OCI attributable to noncontrolling interests	0	0
OCI attributable to Harsco Corporation	92,252	(73,938)
Balances	(422,248)	(514,500)
Cumulative Unrecognized Actuarial Losses on Pension Obligations | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(440,562)
Balances			(440,562)
Unrealized Loss on Marketable Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(9)
OCI before reclassifications	31	(6)
Amounts reclassified from AOCI, net of tax		0
Total OCI	31	(6)
Plus: OCI attributable to noncontrolling interests		0
OCI attributable to Harsco Corporation	31	(6)
Balances	22	(9)
Unrealized Loss on Marketable Securities | Cumulative Effect, Period of Adoption, Adjusted Balance
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances		(3)
Balances			(3)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances	(645,741)	(587,622)	(567,107)
Total OCI	85,602	(58,119)	914
Balances	$ (560,139)	$ (645,741)	(587,622)
Total | Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balances			$ (21,429)

Components of Accumulated Oth_4

Components of Accumulated Other Comprehensive Loss (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenues	$ 1,848,399	$ 1,534,033	$ 1,204,369
Interest expense	(63,235)	(58,196)	(34,024)
Income (loss) from discontinued businesses	(25,863)	20,350	52,937
Total costs and expenses	1,760,023	1,537,339	1,127,966
Income from continuing operations before income taxes	37,506	(54,220)	31,065
Income Tax Expense (Benefit)	9,089	(8,673)	12,728
Net income (loss)	(2,729)	21,975	(512,218)
Other Operating Income (Expense), Net	3,722	(10,072)	$ 8,194
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cumulative Unrecognized Actuarial Losses on Pension Obligations
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total costs and expenses	24,167	25,405
Income Tax Expense (Benefit)	(1,432)	(2,659)
Net income (loss)	22,735	22,746
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension asset transfer - discontinued businesses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of services and products sold	0	5,363
Reclassification out of Accumulated Other Comprehensive Income [Member] | Settlement/curtailment losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	0	18
Reclassification out of Accumulated Other Comprehensive Income [Member] | Settlement/curtailment losses | Discontinued Operations
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	(72)	(110)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	23,657	19,623
Other Operating Income (Expense), Net	0	12,906
Reclassification out of Accumulated Other Comprehensive Income [Member] | Effective Portion of Derivatives Designated as Hedging Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income Tax Expense (Benefit)	(970)	(992)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	582	511
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign currency exchange forward contracts | Effective Portion of Derivatives Designated as Hedging Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenues	(129)	(1,026)
Income from continuing operations before income taxes	3,345	2,578
Net income (loss)	2,375	1,586
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cross-currency interest rate swaps | Effective Portion of Derivatives Designated as Hedging Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	0	(1,015)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest rate swaps | Effective Portion of Derivatives Designated as Hedging Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense	$ (3,474)	$ (2,589)

Two-Year Summary of Quarterly_2

Two-Year Summary of Quarterly Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Product revenues	$ 462,100	$ 470,400	$ 468,700	$ 447,300	$ 431,500	$ 416,600	$ 365,600	$ 320,400	$ 1,848,399	$ 1,534,033	$ 1,204,369
Gross Profit	79,700	95,000	93,200	89,900	86,800	80,500	62,100	62,300
Net income (loss) attributable to Harsco Corporation common stockholders	$ (24,400)	$ 7,600	$ 13,400	$ 100	$ (6,300)	$ (9,600)	$ (10,600)	$ 100	$ (3,249)	$ (26,341)	$ 503,919
Continuing operations (in dollars per share)	$ 0.13	$ 0.06	$ 0.11	$ (0.02)	$ (0.09)	$ (0.12)	$ (0.25)	$ (0.17)	$ 0.28	$ (0.63)	$ 0.13
Discontinued operations (in dollars per share)	(0.43)	0.03	0.06	0.02	0.01	0	0.12	0.17	(0.32)	0.30	6.20
Earnings per share, basic (in dollars per share)	(0.31)	0.10	0.17	0	(0.08)	(0.12)	(0.13)	0	(0.04)	(0.33)	6.33
Continuing operations (in dollars per share)	0.13	0.06	0.11	(0.02)	(0.09)	(0.12)	(0.25)	(0.17)	0.28	(0.63)	0.13
Discontinued operations (in dollars per share)	(0.43)	0.03	0.06	0.02	0.01	0	0.12	0.17	(0.32)	0.30	6.07
Earnings per share, diluted (in dollars per share)	$ (0.30)	$ 0.09	$ 0.17	$ 0	$ (0.08)	$ (0.12)	$ (0.13)	$ 0	$ (0.04)	$ (0.33)	$ 6.19	[1]
[1]	Does not total due to rounding.

SCHEDULE II. VALUATION AND QU_2

SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Accrued Environmental Loss Contingencies, Noncurrent	$ 28,435	$ 29,424
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	7,488	13,265	$ 4,396
Charged to Cost and Expenses	589	1,961	7,123
Due to Currency Translation Adjustments	(206)	(104)	370
Other	(609)	(7,634)	1,376
Balance at End of Period	7,262	7,488	13,265
Deferred Tax Assets - Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	108,563	100,245	112,706
Charged to Cost and Expenses	(4,252)	6,936	(8,545)
Due to Currency Translation Adjustments	(3,502)	1,305	860
Other	(8,424)	77	(4,776)
Balance at End of Period	92,385	108,563	100,245
Valuation Allowance, Tax Credit Carryforward
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance		(15,500)
Valuation Allowance, Deferred Tax Asset, liquidation and Merger of Entities [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance			$ (5,600)
Pension Adjustments
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance	(19,300)	(13,000)
Tax Rate Change
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance	$ (14,400)	$ (3,700)

Subsequent Events (Details)

Subsequent Events (Details) - Revolving Credit Facility	21 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Feb. 22, 2022	Dec. 31, 2021
Subsequent Event [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant						5.75
Forecast
Subsequent Event [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant	4	4	4.50	5.75
Net debt to consolidated adjusted EBITDA ratio covenant, quarterly increase (decrease)	(0.25)
Subsequent Event
Subsequent Event [Line Items]
Net debt to consolidated adjusted EBITDA ratio covenant, increase (decrease) related to divesture of business					(0.25)
Threshold net debt to consolidated adjusted EBITDA ratio covenant					4