Sotera Health (SHC) 10-Q 13 May 21 2021 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2021	May 06, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-39729
Entity Registrant Name	SOTERA HEALTH COMPANY
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3531161
Entity Address, Address Line One	9100 South Hills Blvd
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Broadview Heights
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44147
City Area Code	440
Local Phone Number	262-1409
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	SHC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		282,869,957
Entity Central Index Key	0001822479
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 108,009	$ 102,447
Restricted cash short-term	7	7
Accounts receivable, net of allowance for uncollectible accounts of $603 and $708, respectively	96,393	91,735
Inventories, net	33,375	34,093
Prepaid expenses and other current assets	69,758	64,964
Income taxes receivable	20,825	21,769
Total current assets	328,367	315,015
Property, plant, and equipment, net	611,620	609,814
Operating lease assets	47,117	45,963
Deferred income taxes	8,088	8,424
Investment in unconsolidated affiliate	9,227	13,457
Other assets	9,281	9,304
Other intangible assets, net	656,572	643,366
Goodwill	1,106,728	1,115,936
Total assets	2,777,000	2,761,279
Current liabilities:
Accounts payable	57,174	52,400
Accrued liabilities	56,373	60,518
Deferred revenue	5,958	6,056
Current portion of finance lease obligations	1,108	1,173
Current portion of operating lease obligations	9,631	9,383
Current portion of asset retirement obligations	391	620
Income taxes payable	7,384	10,448
Total current liabilities	138,019	140,598
Total long-term debt, less debt issuance costs and debt discounts	1,837,580	1,824,789
Finance lease obligations, less current portion	33,432	34,939
Operating lease obligations, less current portion	39,806	38,941
Noncurrent asset retirement obligations	45,633	45,013
Deferred lease income	21,362	21,255
Post-retirement obligations	46,959	48,223
Mandatorily redeemable noncontrolling interest	0	13,625
Noncurrent liabilities	18,795	17,506
Deferred income taxes	129,670	121,816
Total liabilities	2,311,256	2,306,705
See Commitments and contingencies note
Equity:
Common stock, with $0.01 par value, 1,200,000 shares authorized; 285,990 shares issued at March 31, 2021 and December 31, 2020, respectively	2,860	2,860
Preferred stock, with $0.01 par value, 120,000 authorized; no shares issued at March 31, 2021 and December 31, 2020, respectively	0	0
Treasury stock, at cost (3,090 and 2,742 shares at March 31, 2021 and December 31, 2020, respectively)	(34,000)	(34,000)
Additional paid-in capital	1,169,852	1,166,412
Retained deficit	(578,286)	(589,128)
Accumulated other comprehensive loss	(97,162)	(93,842)
Total equity attributable to Sotera Health Company	463,264	452,302
Noncontrolling interests	2,480	2,272
Total equity	465,744	454,574
Total liabilities and equity	$ 2,777,000	$ 2,761,279

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for uncollectible accounts	$ 603	$ 708
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,200,000,000	1,200,000,000
Common stock, shares issued (in shares)	285,990,000	285,990,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	120,000,000	120,000,000
Preferred stock, shares issued (in shares)	0	0
Treasury stock (in shares)	3,090,000	2,742,000

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Total net revenues	$ 212,148	$ 188,200
Cost of revenues:
Total cost of revenues	96,776	91,683
Gross profit	115,372	96,517
Operating expenses:
Selling, general and administrative expenses	52,465	37,053
Amortization of intangible assets	16,543	14,599
Total operating expenses	69,008	51,652
Operating income	46,364	44,865
Interest expense, net	21,282	56,562
Loss on extinguishment of debt	14,312	0
Foreign exchange loss (gain)	578	(627)
Other (income) expense, net	(3,890)	3,150
Income (loss) before income taxes	14,082	(14,220)
Provision (benefit) for income taxes	3,017	(12,234)
Net income (loss)	11,065	(1,986)
Less: Net income (loss) attributable to noncontrolling interests	223	(22)
Net income (loss) attributable to Sotera Health Company	10,842	(1,964)
Other comprehensive (loss) income net of tax:
Pension and post-retirement benefits (net of taxes of $84 and $(744), respectively)	(249)	2,207
Interest rate swaps (net of taxes of $0 and $1,234, respectively)	0	(3,479)
Foreign currency translation	(3,086)	(72,967)
Comprehensive income (loss)	7,730	(76,225)
Less: comprehensive income (loss) attributable to noncontrolling interests	208	(22)
Comprehensive income (loss) attributable to Sotera Health Company	$ 7,522	$ (76,203)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.04	$ (0.01)
Diluted (in dollars per share)	$ 0.04	$ (0.01)
Weighted average number of shares outstanding:
Basic (in shares)	278,827	232,400
Diluted (in shares)	278,968	232,400
Service
Revenues:
Total net revenues	$ 188,698	$ 167,405
Cost of revenues:
Total cost of revenues	85,036	83,069
Product
Revenues:
Total net revenues	23,450	20,795
Cost of revenues:
Total cost of revenues	$ 11,740	$ 8,614

Consolidated Statements of Op_2

Consolidated Statements of Operations and Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Pension and post-retirement benefits, tax	$ 84	$ (744)
Interest rate swaps, tax	$ 0	$ 1,234

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net income (loss)	$ 11,065	$ (1,986)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	15,379	16,110
Amortization of intangible assets	22,282	19,913
Loss on extinguishment of debt	14,312	0
Deferred income taxes	(3,637)	(6,683)
Share-based compensation expense	3,449	1,725
Accretion of asset retirement obligations	551	471
Unrealized foreign exchange (gains) / losses	2,354	(4,876)
Unrealized (gain) / loss on embedded derivative instruments	(853)	4,819
Amortization of debt issuance costs	1,663	2,977
Gain (loss) on interest rate swap	0	(4,713)
Other	(2,843)	(2,306)
Changes in operating assets and liabilities:
Accounts receivable	(4,134)	(433)
Inventories	1,099	(1,553)
Other current assets	(2,324)	(1,404)
Accounts payable	6,625	(733)
Accrued liabilities	(5,542)	(8,334)
Income taxes payable / receivable	(4,518)	(8,132)
Other liabilities	1,513	(61)
Other long-term assets	(282)	889
Net cash provided by operating activities	56,159	5,690
Investing activities:
Purchases of property, plant and equipment	(20,942)	(12,989)
Purchase of mandatorily redeemable noncontrolling interest in Nelson Laboratories Fairfield, Inc.	(12,425)	0
Purchase of BioScience Laboratories, LLC, net of cash acquired	(13,152)	0
Net cash used in investing activities	(46,519)	(12,989)
Financing activities:
Proceeds from revolving credit facility	0	50,000
Payments of debt issuance costs	(3,435)	(207)
Payments on long-term borrowings	0	(142)
Other	(348)	(344)
Net cash provided by (used in) financing activities	(3,783)	49,307
Effect of exchange rate changes on cash and cash equivalents	(295)	154
Net increase in cash and cash equivalents, including restricted cash	5,562	42,162
Cash and cash equivalents, including restricted cash, at beginning of period	102,454	63,025
Cash and cash equivalents, including restricted cash, at end of period	108,016	105,187
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	19,745	63,570
Cash paid during the period for income taxes, net of tax refunds received	11,561	1,868
Equipment purchases included in accounts payable	$ 7,389	$ 5,100

Consolidated Statements of Equi

Consolidated Statements of Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings / (Accumulated Deficit)	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Balance (in shares) at Dec. 31, 2019		232,400
Balance at Dec. 31, 2019	$ (641,132)	$ 2,324	$ 0	$ 0	$ (550,511)	$ (94,387)	$ 1,442
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation plans	1,725			1,725
Comprehensive income (loss):
Pension and post-retirement plan adjustments, net of tax	2,207					2,207
Foreign currency translation	(72,967)					(72,967)
Interest rate swaps	(3,479)					(3,479)
Net income (loss)	(1,986)				(1,964)		(22)
Balance (in shares) at Mar. 31, 2020		232,400
Balance at Mar. 31, 2020	(715,632)	$ 2,324	0	1,725	(552,475)	(168,626)	1,420
Balance (in shares) at Dec. 31, 2020		283,248
Balance at Dec. 31, 2020	454,574	$ 2,860	(34,000)	1,166,412	(589,128)	(93,842)	2,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation plans (in shares)		$ (348)
Share-based compensation plans	3,440			3,440
Comprehensive income (loss):
Pension and post-retirement plan adjustments, net of tax	(249)					(249)
Foreign currency translation	(3,086)					(3,071)	(15)
Interest rate swaps	0
Net income (loss)	11,065				10,842		223
Balance (in shares) at Mar. 31, 2021		282,900
Balance at Mar. 31, 2021	$ 465,744	$ 2,860	$ (34,000)	$ 1,169,852	$ (578,286)	$ (97,162)	$ 2,480

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Principles of Consolidation – Sotera Health Company (also referred to herein as the “Company,” “we,” “our,” “us” or “its”), is a global provider of mission-critical sterilization and lab testing and advisory services to the medical device and pharmaceutical industries with operations primarily in the Americas, Europe and Asia. We operate and report in three segments, Sterigenics, Nordion and Nelson Labs. We describe our reportable segments in Note 18, “Segment Information”. All significant intercompany balances and transactions have been eliminated in consolidation. Noncontrolling interests represent the noncontrolling stockholders’ proportionate share of the total equity in the Company’s consolidated subsidiaries. As of March 31, 2021, our subsidiaries were wholly owned by us, except for noncontrolling interests of 15% and 33% in our two China subsidiaries. We consolidate the results of operations of these subsidiaries with our results of operations and reflect the noncontrolling interests in our two China subsidiaries on our Consolidated Statements of Operations and Comprehensive Income (Loss) as “Net income attributable to noncontrolling interests.” On March 11, 2021, we purchased the 15% noncontrolling interest that remained from the August 2018 acquisition of Nelson Laboratories Fairfield, Inc. (“Nelson Labs Fairfield”). This required future purchase was considered mandatorily redeemable, and therefore no earnings were allocated to this noncontrolling interest. See Note 4, “Acquisitions” for additional details. In the first quarter of 2021, we entered into binding agreements to purchase the outstanding noncontrolling interests of 15% and 33% of our two China subsidiaries, respectively. The purchase transactions are expected to close in the second quarter of 2021 for a total purchase price of $8.6 million. In July 2020, we acquired a 60% equity ownership interest in a joint venture to construct an E-beam facility in Alberta, Canada in connection with our acquisition of Iotron Industries Canada, Inc. (“Iotron”). Refer to Note 4, “Acquisitions” for additional information. We have determined this to be an investment in a variable interest entity (“VIE”). The investment is not consolidated as the Company has concluded that we are not the primary beneficiary of the VIE. The Company accounts for the joint venture using the equity method. The investment is reflected within “Investment in unconsolidated affiliates” on the Consolidated Balance Sheets. Use of Estimates – In preparing our consolidated financial statements in conformity with U.S. Generally Accepted Accounting Principles ("GAAP"), we make estimates and assumptions that affect the amounts reported and the accompanying notes. We regularly evaluate the estimates and assumptions used and revise them as new information becomes available. Actual results may vary from those estimates. Interim Financial Statements – The accompanying consolidated financial statements include the assets, liabilities, operating results, and cash flows of the Company and its wholly owned subsidiaries. These financial statements are prepared in accordance with U.S. GAAP for interim financial information and the instructions to the Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These unaudited interim financial statements should be read in conjunction with the Company's annual consolidated financial statements and accompanying notes on Form 10-K for the year ended December 31, 2020.

Recent Accounting Standards

Recent Accounting Standards	3 Months Ended
	Mar. 31, 2021
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Standards	Recent Accounting Standards ASU’s Issued But Not Yet Adopted Under the Jumpstart Our Business Startups Act of 2012, emerging growth companies can delay adopting new or revised accounting standards until such time as those standards apply to private companies. As an emerging growth company, we have elected to take advantage of the extended transition period for complying with new or revised accounting standards until those standards would otherwise apply to private companies or at which time we conclude it is appropriate to avail ourselves of early adoption provisions of applicable standards. As a result, our results of operations and financial statements may not be comparable to the results of operations and financial statements of other companies who have adopted the new or revised accounting standards. In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses (“ASU 2016-13”): Measurement of Credit Losses on Financial Instruments, and subsequently issued additional guidance that modified ASU 2016-13. The standard requires an entity to change its accounting approach in determining impairment of certain financial instruments, including trade receivables, from an “incurred loss” to a “current expected credit loss” model. We intend to adopt the standard as of January 1, 2022. We are currently assessing the effect that ASU 2016-13 will have on our financial position, results of operations, and disclosures. In March 2019, the FASB issued ASU 2019-12 - Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The standard simplifies the accounting for income taxes and makes a number of changes meant to add or clarify guidance on accounting for income taxes. This update is effective for annual financial statement periods beginning after March 15, 2021 and interim periods beginning after March 15, 2022, with early adoption permitted in any interim period for which financial statements have not yet been filed. We are currently assessing the effect that ASU 2019-12 will have on our financial position, results of operations, and disclosures.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition The following table shows disaggregated net revenues from contracts with external customers by timing of revenue and by segment for the three months ended March 31, 2021 and 2020: (thousands of U.S. dollars) Three Months Ended March 31, 2021 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 131,151 $ 25,918 $ — $ 157,069 Over time — — 55,079 55,079 Total $ 131,151 $ 25,918 $ 55,079 $ 212,148 (thousands of U.S. dollars) Three Months Ended March 31, 2020 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 117,280 $ 23,625 $ — $ 140,905 Over time — — 47,295 47,295 Total $ 117,280 $ 23,625 $ 47,295 $ 188,200 Contract Balances As of March 31, 2021, and December 31, 2020, contract assets included in prepaid expenses and other current assets on the Consolidated Balance Sheets totaled approximately $14.1 million and $12.7 million, respectively, resulting from revenue recognized over time in excess of the amount billed to the customer. When we receive consideration from a customer prior to transferring goods or services under the terms of a sales contract, we record deferred revenue, which represents a contract liability. Deferred revenue totaled $6.0 million and $6.1 million at March 31, 2021 and December 31, 2020, respectively. We recognize deferred revenue after all revenue recognition criteria are met.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Acquisitions	Acquisitions Acquisition of BioScience Laboratories, LLC On March 8, 2021, we acquired BioScience Laboratories, LLC (“BioScience”) for approximately $13.2 million, net of $0.8 million of cash acquired plus the contemporaneous repayment of BioScience's outstanding debt of $1.9 million. BioScience is a provider of outsourced topical antimicrobial product testing in the pharmaceutical, medical device, and consumer products industries with one location in Bozeman, Montana. The purchase price of BioScience was allocated to the underlying assets acquired and liabilities assumed based upon management's estimated fair values at the date of acquisition. Changes to the allocation of the purchase price may occur as these measurements are completed. Approximately $8.4 million of goodwill was recorded related to the BioScience acquisition, representing the excess of the purchase price over preliminary estimated fair values of all the assets acquired and liabilities assumed. The Company funded this acquisition using available cash. The acquisition price and the results of operations for this acquired entity are not material in relation to the Company's consolidated financial statements. Acquisition of Mandatorily Redeemable Noncontrolling Interest - Nelson Labs Fairfield On March 11, 2021, we completed the acquisition of the remaining 15% ownership of Nelson Labs Fairfield for $12.4 million, resulting in a gain of $1.2 million included in “Other expense (income), net” in the Consolidated Statements of Operations and Comprehensive Income (Loss) relative to the $13.6 million previously accrued. Pursuant to the terms of the August 2018 acquisition, we initially acquired 85% of the equity interests of Nelson Labs Fairfield in August 2018 and were obligated to acquire the remaining 15% noncontrolling interest within three years from the date of the acquisition. Acquisition of Iotron Industries Canada, Inc. On July 31, 2020, we acquired Iotron Industries Canada, Inc.(“Iotron”) for approximately $105.2 million. Iotron was an independent contact sterilizer with two North American locations in Vancouver, Canada, and Columbia City, Indiana. Each location uses proprietary high energy electron beam technology to process products for orthopedic, medical device, plastics, and agricultural businesses. The acquisition was financed by the issuance of $100.0 million of First Lien Notes due 2026. Refer to Note 9, “Long-Term Debt” for additional details. As part of this acquisition, we also acquired Iotron’s 60% equity ownership interest in a joint venture to construct an E-beam facility in Alberta, Canada. The joint venture is accounted for using the equity method. The opening balance sheet for the Iotron acquisition reflects the net tangible and intangible assets acquired and liabilities assumed at their preliminary estimated fair values at the acquisition date. The preliminary estimated fair value of the underlying acquired assets and assumed liabilities of the Iotron acquisition and the measurement period adjustments recognized during the three months ended March 31, 2021, were as follows: (thousands of U.S. dollars) Allocation of purchase price to the fair value of net assets acquired (net of cash acquired): Amount recognized as of December 31, 2020 Measurement Period Adjustments Amount recognized as of March 31, 2021 Goodwill $ 69,046 $ (17,142) $ 51,904 Intangibles 16,427 26,273 42,700 Property, plant, and equipment 13,812 4,346 18,158 Working capital, net 1,115 2 1,117 Investment in unconsolidated affiliate 12,881 (4,181) 8,700 Assumed long-term liabilities (2,248) — (2,248) Other assets/liabilities, net (5,846) (9,298) (15,144) Total estimated purchase price $ 105,187 $ — $ 105,187 The fair value of all the above assets acquired and liabilities assumed are preliminary in nature since the fair value analyses are not yet complete, including finalizing third party appraisals and analyzing the tax attributes of the fair value adjustments. Changes to the allocation of the purchase price may occur as these analyses are completed. Approximately $51.9 million of goodwill was recorded related to the Iotron acquisition, representing the excess of the purchase price over preliminary estimated fair values of all the assets acquired and liabilities assumed. The fair value allocated to goodwill and tangible and intangible assets are deductible for tax purposes. The qualitative elements of goodwill primarily represent the expanded future growth opportunities for the combined company and the addition of Iotron’s highly skilled workforce. A preliminary valuation was recorded of approximately $39.1 million and $3.6 million for intangible assets as part of the acquisition related to customer relationships and employee non-compete agreements, respectively. The estimated useful lives of the identifiable finite-lived intangible assets range from 5 to 15 years. Iotron’s results of operations are included in our consolidated financial statements from the date of the transaction within the Sterigenics segment. The unaudited pro forma consolidated results for the three months ended March 31, 2020, are reflected in the pro forma table below had the transaction occurred on January 1, 2020. The following unaudited supplemental pro forma financial information is based on our historical consolidated financial statements and Iotron’s historical consolidated financial statements, as adjusted for amortization of acquired intangible assets, an increase in interest expense resulting from interest on the First Lien Notes to finance the acquisition, and to reflect the change in the estimated income tax rate for federal and state purposes. (thousands of U.S. dollars) Three Months Ended March 31, 2020 Net revenues $ 194,402 Net loss (889) In connection with the Iotron acquisition, we incurred approximately $1.0 million in transaction costs for the three months ended March 31, 2020, which were included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations and Comprehensive Income (Loss).

Inventories

Inventories	3 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted primarily of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Raw materials and supplies $ 29,512 $ 29,114 Work-in-process 1,371 846 Finished goods 2,617 4,256 33,500 34,216 Reserve for excess and obsolete inventory (125) (123) Inventories, net $ 33,375 $ 34,093

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted primarily of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Prepaid taxes $ 25,356 $ 22,883 Prepaid business insurance 7,421 10,403 Prepaid rent 1,212 1,170 Customer contract assets 14,133 12,670 Insurance and indemnification receivables 2,751 2,751 Current deposits 797 673 Prepaid maintenance contracts 432 404 Value added tax receivable 1,385 2,094 Prepaid software licensing 1,299 1,181 Stock supplies 3,210 2,715 Other 11,762 8,020 Prepaid expenses and other current assets $ 69,758 $ 64,964

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Changes to goodwill during the three months ended March 31, 2021 were as follows: (thousands of U.S. dollars) Sterigenics Nordion Nelson Labs Total Goodwill at December 31, 2020 $ 683,481 $ 287,932 $ 144,523 $ 1,115,936 BioScience acquisition — — 8,435 8,435 Iotron acquisition measurement period adjustments (17,142) — — (17,142) Changes due to foreign currency exchange rates (2,252) 3,408 (1,657) (501) Goodwill at March 31, 2021 $ 664,087 $ 291,340 $ 151,301 $ 1,106,728 Other intangible assets consisted of the following: (thousands of U.S. dollars) Gross Carrying Amount Accumulated Amortization As of March 31, 2021 Finite-lived intangible assets Customer relationships $ 662,509 $ 322,685 Proprietary technology 89,604 39,707 Trade names 142 100 Land-use rights 9,454 1,364 Sealed source and supply agreements 243,660 98,237 Other 5,675 1,138 Total finite-lived intangible assets 1,011,044 463,231 Indefinite-lived intangible assets Regulatory licenses and other (a) 82,807 — Trade names / trademarks 25,952 — Total indefinite-lived intangible assets 108,759 — Total $ 1,119,803 $ 463,231 As of December 31, 2020 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 634,454 $ 309,428 Proprietary technology 90,964 38,075 Trade names 156 105 Land-use rights 9,489 1,311 Sealed source and supply agreements 240,791 92,953 Other 1,937 519 Total finite-lived intangible assets 977,791 442,391 Indefinite-lived intangible assets Regulatory licenses and other (a) 81,832 — Trade names / trademarks 26,134 — Total indefinite-lived intangible assets 107,966 — Total $ 1,085,757 $ 442,391 (a) Includes certain transportation certifications, a class 1B nuclear license and other intangibles related to obtaining such licensure. These assets are considered indefinite-lived as the decision for renewal by the Canadian Nuclear Safety Commission is highly based on a licensee’s previous assessments, reported incidents, and annual compliance and inspection results. New applications for license can take a significant amount of time and cost; whereas an existing licensee with a historical record of compliance and current operating conditions more than likely ensures renewal for another 10 years license period as Nordion has demonstrated over its 70 years of history. Amounts include the impact of foreign currency translation. Fully amortized amounts are written off. Amortization expense for other intangible assets was $22.3 million ($5.8 million is included in “Cost of revenues” and $16.5 million in “Selling, general and administrative expenses”) in the Consolidated Statements of Operations and Comprehensive Income (Loss) and $19.9 million ($5.3 million is included in “Cost of revenues” and $14.6 million in “Selling, general and administrative expenses”) in the Consolidated Statements of Operations and Comprehensive Income (Loss) for the three months ended March 31, 2021 and 2020, respectively. The estimated aggregate amortization expense for finite-lived intangible assets for each of the next five years and thereafter is as follows: (thousands of U.S. dollars) For the remainder of 2021 $ 65,889 2022 80,665 2023 80,659 2024 79,882 2025 41,982 Thereafter 198,736 Total $ 547,813 The weighted-average remaining useful life of the finite-lived intangible assets was approximately 10 years as of March 31, 2021.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Accrued employee compensation $ 27,651 $ 34,760 Legal reserves 2,751 2,751 Accrued interest expense 764 186 Embedded derivatives 229 670 Professional fees 13,744 12,686 Accrued utilities 2,397 1,864 Insurance accrual 1,886 1,255 Accrued taxes 3,332 2,599 Other 3,619 3,747 Accrued liabilities $ 56,373 $ 60,518

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Term loan, due 2026 $ 1,763,100 $ 1,763,100 Senior notes, due 2026 100,000 100,000 Other long-term debt 1,059 450 Total long-term debt 1,864,159 1,863,550 Less unamortized debt issuance costs and debt discounts (26,579) (38,761) Total long-term debt, less debt issuance costs and debt discounts $ 1,837,580 $ 1,824,789 Debt Facilities Senior Secured Credit Facilities On December 13, 2019, Sotera Health Holdings, LLC (“SHH”), our wholly owned subsidiary, entered into senior secured first lien credit facilities (the “Senior Secured Credit Facilities”), consisting of both a prepayable senior secured first lien term loan (the “Term Loan”) and a senior secured first lien revolving credit facility (the “Revolving Credit Facility”) pursuant to a first lien credit agreement (the “Credit Agreement”). The Term Loan matures on December 13, 2026, and the Revolving Credit Facility's original maturity date was December 13, 2024. On December 17, 2020, we increased the capacity of our Revolving Credit Facility from $190.0 million to $347.5 million. The Senior Secured Credit Facilities also provide SHH the right at any time and under certain conditions to request incremental term loans or incremental revolving credit commitments based on a formula defined in the Senior Secured Credit Facilities. As of March 31, 2021 and December 31, 2020, total borrowings under the Term Loan were $1,763.1 million and $1,763.1 million, respectively, and there were no borrowings outstanding on the Revolving Credit Facility. The weighted average interest rate on borrowings under the Term Loan for the three months ended March 31, 2021 and March 31, 2020 was 3.73% and 6.18%, respectively. On January 20, 2021, we closed on an amendment repricing our Term Loan. The interest rate spread over the London Interbank Offered Rate (“LIBOR”) on the facility was reduced from 450 basis points to 275 basis points, and the facility’s LIBOR floor was reduced from 100 basis points to 50 basis points. The changes result in an effective reduction in current interest rates of 2.25%. In connection with this amendment, we wrote off $11.3 million of unamortized debt issuance and discount costs and incurred an additional $2.9 million of expense related to debt issuance costs attributable to the refinancing. These costs were recorded to “Loss on extinguishment of debt” in our Consolidated Statements of Operations and Comprehensive Income (Loss). As of March 31, 2021 and December 31, 2020, capitalized debt issuance costs totaled $3.1 million and $3.4 million, respectively, and debt discounts totaled $20.0 million and $31.6 million, respectively, related to the Senior Secured Credit Facilities. Such costs are recorded as a reduction of debt on our consolidated balance sheets and amortized as a component of interest expense over the term of the debt agreement. On March 26, 2021, we amended the Revolving Credit Facility, to (i) decrease the Applicable Rate (as defined in the Credit Agreement) related to any Revolving Loans (as defined in the Credit Agreement) from a rate per annum that ranged from an alternative base rate (“ABR”) plus 2.50% to ABR plus 3.00% depending on SHH’s Senior Secured First Lien Net Leverage Ratio to ABR plus 1.75%; and in the case of Eurodollar Loans (as defined in the Credit Agreement) from a rate per annum which ranged from the Adjusted LIBOR plus 3.50% to the Adjusted LIBOR plus 4.00% depending on SHH’s Senior Secured First Lien Net Leverage Ratio (as defined in the Credit Agreement), to the Adjusted LIBOR (as defined in the Credit Agreement) plus 2.75%, and (ii) extend the maturity date of the Revolving Facility from December 13, 2024 to June 13, 2026. The other material terms of the Credit Agreement are unchanged and the amendment does not change the capacity of our Revolving Credit Facility, which is $347.5 million. No unamortized debt issuance costs associated with the Revolving Credit Facility were written off and direct fees and costs incurred in connection with the amendment were immaterial. As of March 31, 2021 and December 31, 2020, there were no borrowings on the Revolving Credit Facility. SHH borrowed $50.0 million on the Revolving Credit Facility during the first quarter of 2020 which was repaid in the second quarter of 2020. The interest rate on the borrowings under the Revolving Credit Facility during 2020 averaged approximately 5.0%. All of SHH’s obligations under the Senior Secured Credit Facilities are unconditionally guaranteed by the Company and each existing and subsequently acquired or organized direct or indirect wholly-owned domestic restricted subsidiary of the Company, with customary exceptions including, among other things, where providing such guarantees is not permitted by law, regulation or contract or would result in material adverse tax consequences. All obligations under the Senior Secured Credit Facilities, and the guarantees of such obligations, are secured by substantially all assets of the borrower and guarantors, subject to permitted liens and other exceptions and exclusions, as outlined in the Senior Secured Credit Facilities. Outstanding letters of credit are collateralized by encumbrances against the Revolving Credit Facility and the collateral pledged thereunder, or by cash placed on deposit with the issuing bank. As of March 31, 2021, the Company had $65.8 million of letters of credit issued against the Revolving Credit Facility, resulting in total availability under the Revolving Credit Facility of $281.7 million. First Lien Notes On July 31, 2020, SHH issued $100.0 million aggregate principal amount of senior secured first lien notes due 2026 (the “First Lien Notes”), which mature on December 13, 2026. The First Lien Notes bear interest at a rate equal to LIBOR subject to a 1.00% floor plus 6.00% per annum. Interest is payable on a quarterly basis with no principal due until maturity. The weighted average interest rate on the First Lien Notes for the three months ended March 31, 2021 was 7.00%. SHH is entitled to redeem all or a portion of the First Lien Notes, at any time and from time to time, subject to certain premiums depending on the date of redemption; any time on or prior to July 31, 2021, a customary make-whole premium applies and, thereafter, specified premiums that decline to zero apply (in each case as described in the indenture governing the First Lien Notes). All of SHH’s obligations under the First Lien Notes are unconditionally guaranteed by the Company and each existing and subsequently acquired or organized direct or indirect wholly-owned domestic restricted subsidiary of SHH, with customary exceptions including, among other things, where providing such guarantees is not permitted by law, regulation or contract or would result in material adverse tax consequences. All obligations under the First Lien Notes, and the guarantees of such obligations, are secured by substantially all of the assets of the borrower and guarantors, subject to permitted liens and other exceptions and exclusions, as outlined in the First Lien Notes. Such collateral is substantially the same collateral that secures the Senior Secured Credit Facilities. Such collateral securing the First Lien Notes ranks pari passu with that of the Senior Secured Credit Facilities. At March 31, 2021 and December 31, 2020, capitalized debt issuance costs were $0.8 million and $0.9 million, respectively, and debt discounts were $2.7 million and $2.8 million, respectively, related to the First Lien Notes, which are recorded as a reduction of debt on our Consolidated Balance Sheets and amortized into interest expense over the term of the debt agreement. 2020 Debt Repayments On November 24, 2020, we closed our initial public offering (the "IPO”), in which we sold 53,590,000 shares of our common stock at a price of $23.00 per share, which included the full exercise by the underwriters of their option to purchase up to an additional 6,990,000 shares of common stock. We raised approximately $1.2 billion in net proceeds after deducting underwriters’ discounts and commissions. We used the net proceeds received by us from the IPO to (i) redeem $770.0 million in aggregate principal amount of the Second Lien Senior Secured Notes with an original maturity date of December 13, 2027 (the "Second Lien Notes”), plus accrued and unpaid interest thereon and $15.4 million of redemption premium, (ii) repurchase 1,568,445 shares of our common stock from certain of our executive officers at a purchase price per share equal to the IPO price per share of our common stock less an amount equal to the underwriting discounts and commissions payable thereon and (iii) repay $341.0 million of the outstanding indebtedness under the Term Loan, plus accrued and unpaid interest thereon. In connection with the debt repayments, we wrote off $28.9 million of debt issuance and discount costs and recognized $15.4 million in premiums paid for the early extinguishment of the Second Lien Notes. We recognized these costs within “Loss on extinguishment of debt” in our Consolidated Statements of Operations and Comprehensive Income (Loss) in the fourth quarter of 2020. Aggregate Maturities Aggregate maturities of the Company’s long-term debt, excluding debt discounts, as of March 31, 2021, are as follows: (thousands of U.S. dollars) 2021 $ — 2022 609 2023 450 2024 — 2025 — Thereafter 1,863,100 Total $ 1,864,159 As referenced above, the Company utilized its IPO proceeds toward prepaying the Second Lien Notes in full as well as prepaying a portion of the Term Loan. The Term Loan prepayment amount eliminated all subsequent scheduled and outstanding repayments of the term borrowings resulting in no remaining short-term commitments.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense is provided on an interim basis based upon our estimate of the annual effective income tax rate. In determining the estimated annual effective income tax rate, we analyze various factors, including projections of our annual earnings and the taxing jurisdictions where the earnings will occur, the impact of state and local taxes, our ability to utilize tax credits and net operating loss carryforwards and available tax planning alternatives. Our effective tax rate was 21.4 % and (86.0)% for the three months ended March 31, 2021 and 2020, respectively. Income tax expense for the three months ended March 31, 2021 differs from the statutory rate primarily due to the impact of the foreign rate differential, global intangible low-tax income (“GILTI”), and a net increase in the valuation allowance attributable to the limitation on the deductibility of interest expense. This was offset by a discrete item, which reversed the valuation allowance on deferred tax assets related to certain asset retirement obligations. Income tax benefit for the three months ended March 31, 2020 differed from the statutory rate primarily due to the impact of the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”), which increased the limitation on the deductibility of interest expense from 30% to 50% for tax years beginning in 2019 or 2020, and other provisions. The increased limitation

Employee Benefits

Employee Benefits	3 Months Ended
	Mar. 31, 2021
Postemployment Benefits [Abstract]
Employee Benefits	Employee Benefits The Company sponsors various post-employment benefit plans including, in certain countries outside the U.S., defined benefit and defined contribution pension plans, retirement compensation arrangements, and plans that provide extended health care coverage to retired employees, the majority of which relate to Nordion. Defined benefit pension plan The interest cost and expected return on plan assets are recorded in “Other income, net” and the service cost component is included in the same financial statement line item as the applicable employee’s wages in the Consolidated Statements of Operations and Comprehensive Income (Loss). The components of net periodic pension cost for the defined benefit plans for the three months ended March 31, 2021 and 2020 were as follows: Three Months Ended March 31, (thousands of U.S. dollars) 2021 2020 Service cost $ 298 $ 276 Interest cost 1,613 2,007 Expected return on plan assets (3,557) (3,599) Amortization of net actuarial loss 267 197 Net periodic benefit $ (1,379) $ (1,119) Other benefit plans Other benefit plans include a supplemental retirement arrangement, a retirement and termination allowance, and post-retirement benefit plans, which include contributory health and dental care benefits and contributory life insurance coverage. All but one, non-pension post-employment benefit plans are unfunded. The components of net periodic pension cost for the other benefit plans for the three months ended March 31, 2021 and 2020 were as follows: Three Months Ended March 31, (thousands of U.S. dollars) 2021 2020 Service cost $ 7 $ 7 Interest cost 59 73 Amortization of net actuarial (gain) loss 8 13 Net periodic benefit cost $ 74 $ 93 We currently expect funding requirements of approximately $2.8 million in each of the next five years to fund the regulatory solvency deficit, as defined by Canadian federal regulation, which require solvency testing on defined benefit pension plans.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
Related Parties	Related PartiesWe do business with a number of companies affiliated with Warburg Pincus and GTCR, which we refer to collectively as the “Sponsors,” who continue to have substantial control over us. All transactions with these companies have been conducted in the ordinary course of our business and are not material to our operations.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) Amounts in accumulated other comprehensive income (loss) are presented net of the related tax. Foreign currency translation is not adjusted for income taxes. Changes in our accumulated other comprehensive income (loss) balances, net of applicable tax, were as follows: (thousands of U.S. dollars) Defined Benefit Plans Foreign Currency Translation Interest Rate Swaps Total Beginning balance – January 1, 2021 $ (44,143) $ (49,699) $ — $ (93,842) Other comprehensive income (loss) before reclassifications (524) (3,071) — (3,595) Amounts reclassified from accumulated other comprehensive income (loss) 275 (a) — — 275 Net current-period other comprehensive income (loss) (249) (3,071) — (3,320) Ending balance – March 31, 2021 $ (44,392) $ (52,770) $ — $ (97,162) Beginning balance – January 1, 2020 $ (27,113) $ (67,453) $ 179 $ (94,387) Other comprehensive income (loss) before reclassifications 2,207 (72,967) (3,292) (74,052) Amounts reclassified from accumulated other comprehensive income (loss) — — (187) (b) (187) Net current-period other comprehensive income (loss) 2,207 (72,967) (3,479) (74,239) Ending balance – March 31, 2020 $ (24,906) $ (140,420) $ (3,300) $ (168,626) (a) For defined benefit pension plans, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Other income, net” within the Consolidated Statements of Operations and Comprehensive Income (Loss). (b) For interest rate swaps, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Interest expense, net” within the Consolidated Statements of Operations and Comprehensive Income (Loss).

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Pre-IPO Awards Restricted stock distributed in respect of pre-IPO Class B-1 time vesting units vests on a daily basis pro rata over the five Restricted stock distributed in respect of pre-IPO Class B-2 Units (which were considered performance vesting units) are scheduled to vest only upon satisfaction of certain thresholds. These units generally vest as of the first date on which (i) our Sponsors have received actual cash proceeds in an amount equal to or in excess of at least two and one-half times their invested capital in Sotera Health Topco Parent, L.P. (of which the Company was a direct wholly owned subsidiary prior to the IPO) and (ii) the Sponsors’ internal rate of return exceeds twenty percent, subject to such grantee’s continued services through such date. In the event of a change in control of the Company, any outstanding shares of our common stock distributed in respect of Class B-2 Units that remain unvested immediately following the consummation of such a change in control of the Company shall be immediately canceled and forfeited without compensation. Stock based compensation expense attributed to the pre-IPO Class B-2 awards was recorded in the fourth quarter of 2020 as the related performance conditions were considered probable of achievement and the implied service conditions were met. As of March 31, 2021, these awards remain unvested. We recognized $0.7 million and $1.7 million of share-based compensation expense related to the pre-IPO Class B-1 awards for the three months ended March 31, 2021 and 2020, respectively. A summary of the activity for the three months ended March 31, 2021 related to the restricted stock awards distributed to the Company service providers in respect of the pre-IPO awards (Class B-1 and B-2 Units) is presented below: Restricted Stock - Pre- IPO B-1 Restricted Stock - Pre- IPO B-2 Unvested at December 31, 2020 2,201,239 2,323,333 Forfeited (43,361) (254,839) Vested (228,862) — Unvested at March 31, 2021 1,929,016 2,068,494 2020 Omnibus Incentive Plan We maintain a long-term incentive plan (the “2020 Omnibus Incentive Plan” or the “2020 Plan”) that allows for grants of incentive stock options to employees (including employees of any of our subsidiaries), nonstatutory stock options, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and other cash-based, equity-based or equity-related awards to employees, directors, and consultants, including employees or consultants of our subsidiaries. We recognized $2.8 million ($1.3 million for stock options and $1.5 million for RSUs) of share-based compensation expense for these awards in our Consolidated Statements of Operations and Comprehensive Income (Loss), in “Selling, general and administrative expenses,” for the three months ended March 31, 2021. Stock Options Stock options have a four Number of Shares Weighted- average Exercise Price At December 31, 2020 2,389,258 $ 23.00 Granted 20,407 26.26 Forfeited (9,316) 23.00 Exercised — — At March 31, 2021 2,400,349 $ 23.03 RSUs RSUs generally vest ratably over a period of one Number of Shares Weighted- average Grant Date Fair Value Unvested at December 31, 2020 771,276 $ 23.00 Granted 10,851 26.03 Forfeited (24,999) 23.00 Vested — — Unvested at March 31, 2021 757,128 $ 23.05

Earnings (Loss) Per Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic earnings (loss) per share represents the amount of income (loss) attributable to each common share outstanding. Diluted earnings (loss) per share represents the amount of income (loss) attributable to each common share outstanding adjusted for the effects of potentially dilutive common shares. Potentially dilutive common shares include stock options and other stock-based awards. In the periods where the effect would be antidilutive, potentially dilutive common shares are excluded from the calculation of diluted earnings per share. In periods in which the Company has net income, earnings per share is calculated using the two-class method. This method is required as unvested restricted stock distributed in respect of pre-IPO Class B-1 and B-2 awards have the right to receive non-forfeitable dividends or dividend equivalents if the Company were to declare dividends on its common stock. Pursuant to the two-class method, earnings for each period are allocated on a pro-rata basis to common stockholders and unvested pre-IPO Class B-1 and B-2 restricted stock awards. Diluted earnings per share is computed using the more dilutive of (a) the two-class method, or (b) treasury stock method, as applicable, to the potentially dilutive instruments. In periods in which the Company has a net loss, the two-class method is not applicable because the pre-IPO Class B-1 and B-2 restricted stock awards do not participate in losses. Our basic and diluted earnings per common share are calculated as follows: Three Months Ended in thousands of U.S. dollars and share amounts (except per share amounts) March 31, March 31, Earnings (Loss): Net income (loss) $ 11,065 $ (1,986) Less: Net income (loss) attributable to noncontrolling interests 223 (22) Less: Allocation to participating securities 157 — Net income (loss) attributable to Sotera Health Company common shareholders $ 10,685 $ (1,964) Weighted Average Common Shares: Weighted-average common shares outstanding - basic 278,827 232,400 Dilutive effect of potential common shares 141 — Weighted-average common shares outstanding - diluted (a) 278,968 232,400 Earnings (loss) per Common Share: Net income (loss) attributable to Sotera Health Company common shareholders - basic $ 0.04 $ (0.01) Net income (loss) attributable to Sotera Health Company common shareholders - diluted 0.04 (0.01) (a) A n additional 2,400,349 and 3,645 equivalent shares related to stock options and RSUs, respectively, issued in connection with the 2020 Omnibus Incentive Plan were excluded from the calculation of diluted weighted average common shares outstanding for the three months ended March 31, 2021 as they were anti-dilutive . For the three months ended March 31, 2020, there were no potentially dilutive common shares outstanding.

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, we may be subject to various lawsuits and other claims in the ordinary course of our business. In addition, from time to time, we receive communications from government or regulatory agencies concerning investigations or allegations of noncompliance with laws or regulations in jurisdictions in which we operate. We establish reserves for specific liabilities in connection with regulatory and legal actions that we determine to be both probable and reasonably estimable. No material amounts have been accrued in our consolidated financial statements with respect to any loss contingencies. In certain of the matters described below, we are not able to make a reasonable estimate of any liability because of the uncertainties related to the outcome and/or the amount or range of loss. While it is not possible to determine the ultimate disposition of each of these matters, we do not expect that the ultimate resolution of pending regulatory and legal matters in future periods, including the matters described below, will have a material effect on our financial condition or results of operations. Despite the above, the Company may incur material defense and settlement costs, diversion of management resources and other adverse effects on our business, financial condition, or results of operations. FM Global Business Interruption Claim (NRU Outage) Nordion, due to the shutdown of AECL’s NRU reactor in 2009, suffered a cessation of supply of radioisotopes and business interruption loss. Nordion, by Statement of Claim dated October 22, 2010, issued in Ontario Superior Court an action against the insurer, Factory Mutual Insurance Company (FM Global), claiming $25.0 million USD in losses resulting from the shutdown of AECL’s reactor and its inability to supply radioisotopes through the specified period of approximately 15 months. FM Global objected to Nordion’s claim. Trial commenced in March 2019 and was completed in September 2019. On March 30, 2020, Nordion received a favorable judgment in the amount of $25.0 million USD, plus pre-judgment interest, for a total judgment value of $39.8 million USD, or $56.4 million CAD based on exchange rates approved by the trial court. In addition, costs and disbursements have been assessed and awarded by the trial court in favor of Nordion in the approximate amount of $1.1 million CAD ($0.8 million USD) and $161,863 CAD ($0.1 million USD), respectively. On April 27, 2020, FM Global appealed the judgment. In January 2021, The Insurance Bureau of Canada was granted leave to intervene in the appeal. Hearing before the Court of Appeal was held on April 15, 2021. Pending a favorable judgment in the appellate court, any final proceeds would be subject to post judgment interest, a contingent fee owed to legal counsel and applicable taxes. As the judgment is considered a contingent gain, any favorable outcome will be recognized in a future period when all appeals are exhausted. It is anticipated that the overall appeal process could take a year or more to complete. Willowbrook, Illinois – Government Litigation On October 30, 2018, the Illinois Attorney General and the State’s Attorney of DuPage County, Illinois, sued Sterigenics U.S., LLC (the “IAG Action”), alleging that authorized EO air emissions from a commercial sterilization facility Sterigenics formerly operated in Willowbrook, Illinois “cause, threaten, or allow air pollution” in violation of the Illinois Environmental Protection Act. The IAG Action did not assert that Sterigenics violated its permit from the Illinois Environmental Protection Agency (“IEPA”) authorizing Sterigenics’ release of regulated levels of EO at the Willowbrook facility. On February 15, 2019, the acting IEPA director, John Kim, issued a “Seal Order” effectively precluding Sterigenics’ operations at the Willowbrook facility based on many of the same allegations asserted in the IAG Action. Sterigenics disputed those allegations and opposed the IEPA’s Seal Order. The Seal Order was resolved by a Consent Order entered on September 6, 2019. The Consent Order provided that Sterigenics did not admit the allegations of the IAG Action, provided for the removal of the Seal Order and allowed the Willowbrook facility to reopen upon implementation of supplemental emissions control measures consistent with a new law that became effective in Illinois in June 2019 and an IEPA permit, which the IEPA approved in September 2019. Following entry of the Consent Order, the Seal Order was withdrawn. On September 30, 2019, Sterigenics announced the closure of the Willowbrook facility due to the inability to reach an agreement with its landlord to renew the facility’s lease and the unstable legislative and regulatory landscape in Illinois. Sterigenics is in the process of decommissioning the facility and completing the work required by the terms of its lease to return the property to the landlord. On October 20, 2020 Sterigenics, the Illinois Attorney General and the State’s Attorney of DuPage County filed a Joint Motion to Terminate Consent Order, stating that the community projects which Sterigenics voluntarily agreed to fund have been completed and funded as required by the Consent Order, and that Sterigenics has permanently ceased operations and surrendered all permits for its operations in Willowbrook, Illinois. On October 27, 2020 the DuPage County Circuit Court entered the Agreed Order Terminating Consent Order. Ethylene Oxide Tort Litigation - Illinois Since September 2018, tort lawsuits on behalf of approximately 835 personal injury plaintiffs (which are further described in the following paragraphs) have been filed in Illinois state courts against Sotera Health LLC, Sterigenics U.S., LLC, GTCR, LLC and other parties related to Sterigenics’ Willowbrook, Illinois operations. Specifically, those plaintiffs allege that they suffered personal injuries including cancer and other diseases, or wrongful death, resulting from purported emissions and releases of EO from the Willowbrook facility. Additional derivative claims are alleged on behalf of other individuals related to these personal injury plaintiffs. Plaintiffs seek damages in an amount to be determined by the trier of fact. Sterigenics denies these allegations and intends to vigorously defend against these claims. Plaintiffs have voluntarily dismissed without prejudice a number of cases since September 2018, including certain individual cases alleging personal injuries and two class actions seeking damages for alleged diminution of property values. Sterigenics sought consolidation of the cases for pretrial purposes, and in October 2019 obtained an order consolidating the then-pending cases and related cases filed in the future before Judge Lawler in the Cook County Circuit Court, Illinois (the “Consolidated Case”). All plaintiffs in the Consolidated Case filed a single Master Complaint on October 24, 2019 by which Sotera Health LLC was added as a co-defendant, followed by a First Amended Master Complaint on January 31, 2020. On April 28, 2020, the defendants filed motions to dismiss the claims in the First Amended Master Complaint. On August 17, 2020, the Court entered an order largely denying the motions to dismiss, and the same day plaintiffs filed a Second Amended Master Complaint. Plaintiffs filed a Third Amended Master Complaint on October 30, 2020 adding Griffith Foods Group, Inc., Griffith Foods, Inc., Griffith Foods International, Inc. and Griffith Foods Worldwide Inc. as defendants. Defendants’ responses to the Third Amended Master Complaint were filed on or about December 1, 2020, including a motion to dismiss by Griffith Foods Group, Inc., Griffith Foods, Inc., Griffith Foods International, Inc. and Griffith Foods Worldwide, Inc. That motion was granted in part on March 16, 2021 and plaintiffs were granted leave to file a Fourth Amended Master Complaint. The Fourth Amended Master Complaint was filed on April 16, 2021, including claims against Griffith Foods International, Inc. but not the other Griffith entities. All defendants’ responses to the Fourth Amended Master Complaint are due by May 14, 2021. Written and deposition fact discovery is on-going in the Consolidated Case. Currently, there are no dates set for the close of fact discovery, for expert discovery or for dispositive motion practice. Plaintiffs have not yet made any specific damages claims. Trials in five of the individual cases now included in the Consolidated Case had previously been scheduled to begin in 2021. Based on the Court's administrative orders related to the impact of COVID-19 on jury trials, however, and subject to the Court's discretion to make changes, we anticipate that the earliest any of the individual cases in the Consolidated Case will be tried will be 2022 and that trials will be scheduled in roughly the order in which the individual cases were filed. Ethylene Oxide Tort Litigation – Georgia On May 19, 2020, a lawsuit against Sotera Health LLC, Sterigenics U.S., LLC and other parties was filed in the State Court of Cobb County, Georgia by 53 employees of a contract sterilization customer of Sterigenics. In the operative complaint, Plaintiffs claim personal injuries resulting from alleged exposure to residual EO while working at the customer’s distribution center in Lithia Springs, Georgia, allege they were unaware that they were being exposed to EO in their workplace and seek damages in an amount to be determined by the trier of fact. Defendants filed motions to dismiss and answers to the Complaint on April 30, 2021. All defendants are being defended and indemnified by Sterigenics’ contract sterilization customer (plaintiffs’ employer and a co-defendant in the lawsuit). In May 2020, the Cobb County, Georgia Board of Tax Assessors reduced certain residential property value assessments around the Sterigenics Atlanta facility by 10% citing an “Epd-identified environmental issue,” without supporting market data. On August 14, 2020, Sterigenics U.S., LLC filed a lawsuit against members of the Cobb County Board of Tax Assessors in the U.S. District Court for the Northern District of Georgia, seeking a declaration that the reduction in property value assessments is arbitrary and unlawful and is causing Sterigenics reputational and imminent economic harm. On February 5, 2021 the Court issued an order finding that Sterigenics lacks standing to obtain the relief sought and dismissed the case. Sterigenics has appealed that decision to the 11th Circuit Court of Appeals and anticipates that appellate briefing will be completed before the end of August 2021. Since August 17, 2020, six lawsuits against Sotera Health LLC, Sterigenics U.S., LLC and other parties have been filed by plaintiffs in the State Court of Cobb County, Georgia and the State Court of Gwinnett County, Georgia in which plaintiffs allege that they suffered personal injuries and loss of consortium resulting from emissions and releases of EO from Sterigenics’ Atlanta facility. Our subsidiaries are also defendants in lawsuits alleging that the Atlanta facility has devalued and harmed plaintiffs’ use of real properties they own in Smyrna, Georgia and caused other damages. Plaintiffs in these cases seek various forms of relief including damages in amounts to be determined by the trier of fact. Sotera Health LLC filed motions to dismiss in each case on personal jurisdiction grounds. That motion was denied in one case pending in the State Court of Gwinnett County and the other motions remain pending. Sterigenics U.S., LLC and Sotera Health LLC filed a motion to dismiss the strict liability claim in each case. That motion was denied in one case pending in the State Court of Gwinnett County and the other motions remain pending. Suspension of Georgia Facility Operations & Related Litigation On August 7, 2019, Sterigenics U.S., LLC entered into a voluntary Consent Order with the Georgia Environmental Protection Division (“EPD”) under which Sterigenics agreed to install emissions reduction enhancements at its Atlanta facility to further reduce the facility’s EO emissions below already permitted levels. Sterigenics voluntarily suspended operations at the facility in early September 2019 to expedite completion of the enhancements. Installation of these enhancements is complete, and Sterigenics successfully tested the enhanced emissions controls in cooperation with EPD during the second quarter of 2020 while the facility was in operation. In October 2019, while Sterigenics had voluntarily suspended the facility’s operations, Cobb County, Georgia officials asserted that the facility had an incorrect “certificate of occupancy” and could not resume operations without obtaining a new certificate of occupancy after a third-party code compliance review they required. After the Cobb County officials would not allow Sterigenics to resume operations, on March 30, 2020, Sterigenics U.S., LLC filed a lawsuit in the United States District Court for the Northern District of Georgia against Cobb County, Georgia and Cobb County officials Nicholas Dawe and Kevin Gobble. In the lawsuit, Sterigenics sought immediate injunctive relief and permanent declaratory relief to resume normal operations of the Atlanta facility in the interest of public health and on the basis that the positions asserted by Cobb County were unfounded. On April 1, 2020 the Court entered a Temporary Restraining Order prohibiting Cobb County officials from precluding or interfering with the facility’s normal operations. On April 8, 2020, the Court entered a Consent Order extending the Temporary Restraining Order and allowing the facility to continue normal operations until entry of a final judgment in the case. Defendants filed a motion to dismiss the claims. On November 9, 2020, the Court held a hearing and denied the motion to dismiss. The parties are conducting discovery, which is presently scheduled to end on July 23, 2021. A settlement conference is scheduled to be held by September 27, 2021. Ethylene Oxide Litigation – New Mexico On December 22, 2020 the New Mexico Attorney General filed a lawsuit in the Third Judicial District Court, Doña Ana County, New Mexico (“the Third Judicial District”) against the Company, Sterigenics U.S., LLC and other subsidiaries alleging that emissions of EO from Sterigenics U.S., LLC’s sterilization facility in Santa Teresa, New Mexico constitute a public nuisance and have deteriorated the air quality in Santa Teresa and surrounding communities and materially contributed to increased health risks suffered by residents of those communities. The Complaint asserts claims for public nuisance, negligence, strict liability, violations of New Mexico’s Public Nuisance Statute and Unfair Practices Act and a request for a temporary restraining order and preliminary injunctive relief. On December 28, 2020 Sterigenics U.S., LLC removed the case to the United States District Court for the District of New Mexico. On April 13, 2021 the case was remanded to the Third Judicial District where Plaintiff’s Emergency Motion for Temporary Restraining Order and Preliminary Injunction has been scheduled for a preliminary injunction hearing on May 26, 2021. The Emergency Motion does not demand facility closure but seeks an order requiring Defendants to cease any and all uncontrolled emissions or releases of EO from the Santa Teresa facility, including by making certain modifications to sterilization processes at the facility. * * * We carry insurance for alleged environmental liabilities (including litigation like that pending in Illinois, Georgia and New Mexico described above), with limits of $10.0 million per occurrence and $20.0 million in the aggregate. The per occurrence limit related to the Willowbrook government and EO tort litigation was fully utilized by June 30, 2020. Additional personal injury, property devaluation or other lawsuits may be filed in the future against us or our subsidiaries relating to Sterigenics’ Willowbrook, Atlanta, Santa Teresa or other EO sterilization facilities. The Company, Sterigenics U.S., LLC and other Company subsidiaries intend to defend themselves vigorously in all such current or future EO litigation. While an adverse outcome in one or more of the proceedings could have a material adverse effect on our business, financial condition and results of operations, no contingency reserve has been reflected in our consolidated financial statements as a loss is not deemed probable, nor is a loss or range of losses reasonably estimable.

Financial Instruments and Finan

Financial Instruments and Financial Risk	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments and Financial Risk	Financial Instruments and Financial Risk Derivative Instruments We do not use derivatives for trading or speculative purposes and are not a party to leveraged derivatives. Derivatives Designated in Hedge Relationships During the third quarter of 2019, we entered into two interest rate swap agreements to hedge our exposure to interest rate movements and to manage interest expense related to our then outstanding variable-rate debt. The notional amount of the interest rate swap agreements totaled $1,000.0 million. These swaps were designated as cash flow hedges and were designed to hedge the variability of cash flows attributable to changes in LIBOR, the benchmark interest rate being hedged. We received interest at one-month LIBOR and paid a fixed interest rate under the terms of the swap agreement. The swap agreements terminated on August 31, 2020. Derivatives Not Designated in Hedge Relationships In October 2017, we entered into two interest rate cap agreements with a total notional amount of $400.0 million for a total option premium of $0.6 million; these agreements terminated on September 30, 2020. The interest rate caps limited the Company’s cash flow exposure related to LIBOR under the variable rate Term Loan borrowings to 3.0%. In June 2020, SHH entered into two interest rate cap agreements with notional amounts of $1,000.0 million and $500.0 million, respectively, for a total option premium of $0.3 million. These instruments were initially scheduled to terminate on August 31, 2021 and February 28, 2022, respectively. The interest rate caps limit our cash flow exposure related to the LIBOR base rate under a portion of our variable rate borrowings to 1.0%. In February 2021, we amended the two interest rate cap agreements referenced above to reduce the strike rate from 1.0% to 0.5%, and extend the termination date of the $1,000.0 million notional cap to September 30, 2021. Premiums paid to amend the interest rate caps were immaterial. We also entered into two additional interest rate cap agreements in February 2021 with a combined notional amount of $1,000.0 million, for a total option premium of $0.4 million. These instruments are effective September 30, 2021, and will terminate on March 31, 2022. The amended and new interest rate caps limit our cash flow exposure related to LIBOR under a portion of our variable rate borrowings to 0.5%. The interest rate caps were entered into to manage economic risks associated with our variable rate borrowings, but were not designated in hedge relationships. These instruments are recorded at fair value on the Consolidated Balance Sheets, with any changes in the value being recorded in “Interest expense, net” in the Consolidated Statements of Operations and Comprehensive Income (Loss). The Company also entered into foreign currency forward contracts to manage foreign currency exchange rate risk of our intercompany loans in certain of our international subsidiaries. The foreign currency forward contracts expire on a monthly basis. The fair value of the outstanding foreign currency forward contracts was zero as of March 31, 2021 and December 31, 2020, respectively. Embedded Derivatives We have embedded derivatives in certain of our customer and supply contracts as a result of the currency of the contract being different from the functional currency of the parties involved. Changes in the fair value of the embedded derivatives are recognized in “Other income, net” in the Consolidated Statements of Operations and Comprehensive Income (Loss). The following table provides a summary of the notional and fair values of our derivative instruments: March 31, 2021 December 31, 2020 (in U.S. Dollars; notional in millions, fair value in thousands) Fair Value Fair Value Notional Derivative Derivative Notional Derivative Derivative Derivatives not designated as hedging instruments Interest rate caps $ 2,500.0 $ 9 $ — $ 1,500.0 $ 7 $ — Embedded derivatives 77.7 (a) 403 229 83.3 — 670 Total $ 2,577.7 $ 412 $ 229 $ 1,583.3 $ 7 $ 670 (a) Represents the total notional amounts for certain of the Company’s supply and sales contracts accounted for as embedded derivatives. The interest rate caps and embedded derivative assets are included in “Prepaid expenses and other current assets” on our consolidated balance sheets. Embedded derivative liabilities are included in “Accrued liabilities” on the Consolidated Balance Sheets. The following tables summarize the activities of our derivative instruments for the periods presented, and the line item they are recorded in in the Consolidated Statements of Operations and Comprehensive Income (Loss): (thousands of U.S. dollars) Three Months March 31, 2021 2020 Unrealized loss on interest rate caps recorded in interest expense, net $ 90 $ — Unrealized (gain) loss on embedded derivatives recorded in other income, net (853) 4,819 Realized gain on foreign currency forward contracts recorded in foreign exchange (gain) loss (2,374) — In addition, during the three months ended March 31, 2020, we recognized $3.5 million of losses, net of tax, in accumulated other comprehensive income (loss) related to the change in fair value of the interest rate swaps. Credit Risk Certain of our financial assets, including cash and cash equivalents, are exposed to credit risk. We are also exposed, in our normal course of business, to credit risk from our customers. As of March 31, 2021 and December 31, 2020, accounts receivable was net of an allowance for uncollectible accounts of $0.6 million and $0.7 million, respectively. Credit risk on financial instruments arises from the potential for counterparties to default on their contractual obligations to us. We are exposed to credit risk in the event of non-performance, but do not anticipate non-performance by any of the counterparties to our financial instruments. We limit our credit risk by dealing with counterparties that are considered to be of high credit quality. In the event of non-performance by counterparties, the carrying value of our financial instruments represents the maximum amount of loss that would be incurred. Fair Value Hierarchy The fair value of our financial instruments 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. The valuation techniques we would use to determine such fair values are described as follows: Level 1—fair values determined by inputs utilizing quoted prices in active markets for identical assets or liabilities; Level 2—fair values based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable; Level 3—fair values determined by unobservable inputs reflecting our own assumptions, consistent with reasonably available assumptions made by other market participants. The following table discloses the fair value of our financial assets and liabilities: As of March 31, 2021 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives not designated as hedging instruments (a) Interest rate caps $ 9 $ — $ 9 $ — Embedded derivative assets 403 — 403 — Embedded derivative liabilities (229) — (229) — Long-Term Debt (b) Term loan, due 2026 1,740,071 — 1,760,896 — Senior notes, due 2026 96,458 — 97,587 — Other long-term debt 1,051 — 1,051 — Finance Lease Obligations (with current portion) (c) 34,540 — 34,540 — As of December 31, 2020 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives not designated as hedging instruments (a) Interest rate caps $ 7 $ — $ 7 $ — Embedded derivative liabilities (670) — (670) — Long-Term Debt (b) Term loan, due 2026 1,728,018 — 1,772,180 — Senior notes, due 2026 96,329 — 99,863 — Other long-term debt 442 — 442 — Finance Lease Obligations (with current portion) (c) 36,112 — 36,112 — (a) Derivatives that are not designated as hedging instruments are measured at fair value with gains or losses recognized immediately in the Consolidated Statements of Operations and Comprehensive Income (Loss). Interest rate caps are valued using pricing models that incorporate observable market inputs including interest rate and yield curves. Embedded derivatives are valued using internally developed models that rely on observable market inputs including foreign currency forward curves. (b) Carrying amounts of long-term debt instruments are reported net of discounts and debt issuance costs. The estimated fair value of these instruments is based on information provided by the agent under the Company’s senior secured credit facility. Fair value approximates carrying value for “Other long-term debt.” (c) Fair value approximates carrying value.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information We identify our operating segments based on the way we manage, evaluate and internally report our business activities for purposes of allocating resources and assessing performance. We have three reportable segments: Sterigenics, Nordion and Nelson Labs. We have determined our reportable segments based upon an assessment of organizational structure, service types, and internally prepared financial statements. Our chief operating decision maker evaluates performance and allocates resources based on net revenues and segment income after the elimination of intercompany activities. The accounting policies of our reportable segments are the same as those described in Note 1, “Significant Accounting Policies” of our 2020 Form 10-K. Sterigenics The Sterigenics segment provides outsourced terminal sterilization and irradiation services for the medical device, pharmaceutical, food safety and advanced applications markets. Nordion Nordion is a global provider of Co-60 and gamma irradiators, which are key components to the gamma sterilization process. Nelson Labs Nelson Labs provides outsourced microbiological and analytical chemistry testing and advisory services for the medical device and biopharmaceutical industries. For the three months ended March 31, 2021, three customers reported within the Nordion segment individually represented 10% or more of the segment’s total net revenues. These customers represented 23.7%, 20.0%, and 12.2% of the total segment’s external net revenues for the three months ended March 31, 2021. For the three months ended March 31, 2020, two customers reported within the Nordion segment individually represented 10% or more of the segment's total net revenues. These customers represented 18.7% and 11.6% of the total segment's external net revenues for the three months ended March 31, 2020. (thousands of U.S. dollars) Three Months Ended March 31, 2021 Sterigenics Nordion Nelson Labs Consolidated Net revenues (a) $ 131,151 $ 25,918 $ 55,079 $ 212,148 Segment income (b) 68,461 13,786 23,070 105,317 Capital expenditures 19,514 489 939 20,942 Three Months Ended March 31, 2020 Sterigenics Nordion Nelson Labs Consolidated Net revenues (a) $ 117,280 $ 23,625 $ 47,295 $ 188,200 Segment income (b) 61,091 13,022 17,770 91,883 Capital expenditures 10,940 1,234 815 12,989 (a) Revenues are reported net of intersegment sales. Our Nordion segment recognized $10.5 million and $10.9 million in revenues from sales to our Sterigenics segment for the three months ended March 31, 2021 and 2020, respectively, that is not reflected in net revenues in the table above. Intersegment sales for Sterigenics and Nelson Labs are immaterial for both periods. (b) Segment income is only provided on a net basis to the chief operating decision maker and is reported net of intersegment profits. Corporate operating expenses for executive management, accounting, information technology, legal, human resources, treasury, corporate development, tax, purchasing, and marketing are allocated to the segments based on total revenue. Total assets and depreciation and amortization expense by segment are not readily available and are not reported separately to the chief operating decision maker. A reconciliation of segment income to consolidated income (loss) before taxes is as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2021 2020 Segment income $ 105,317 $ 91,883 Less adjustments: Interest expense, net 21,282 56,562 Depreciation and amortization (a) 37,661 36,023 Share-based compensation (b) 3,449 1,725 (Gain) loss on foreign currency and embedded derivatives (c) (336) 4,267 Acquisition and divestiture related charges, net (d) (185) 994 Business optimization project expenses (e) 261 1,049 Plant closure expenses (f) 542 771 Loss on extinguishment of debt (g) 14,312 — Professional services relating to EO sterilization facilities (h) 13,399 4,146 Accretion of asset retirement obligation (i) 551 490 COVID-19 expenses (j) 299 76 Consolidated income (loss) before taxes $ 14,082 $ (14,220) (a) Includes depreciation of Co-60 held at gamma irradiation sites. (b) Represents non-cash share-based compensation expense. (c) Represents the effects of (i) fluctuations in foreign currency exchange rates, primarily related to remeasurement of intercompany loans denominated in currencies other than subsidiaries’ functional currencies, and (ii) non-cash mark-to-fair value of embedded derivatives relating to certain customer and supply contracts at Nordion. (d) Represents (i) certain direct and incremental costs related to the acquisitions of BioScience in 2021, Iotron in July 2020 and Nelson Labs Fairfield in 2018 (including the first quarter 2021 gain on the mandatorily redeemable noncontrolling interest as described in Note 4, “Acquisitions”), and certain related integration efforts as a result of those acquisitions, (ii) the earnings impact of fair value adjustments (excluding those recognized within amortization expense) resulting from the businesses acquired, and (iii) transition services income and non-cash deferred lease income associated with the terms of the divestiture of the Medical Isotopes business in 2018. (e) Represents professional fees, contract termination and exit costs, severance and other payroll costs, and other costs associated with business optimization and cost savings projects relating to the integration of Nelson Labs, the Sotera Health rebranding, operating structure realignment and other process enhancement projects. (f) Represents professional fees, severance and other payroll costs, and other costs including ongoing lease and utility expenses associated with the closure of the Willowbrook, Illinois facility. (g) Represents expenses incurred in connection with the repricing of our Term Loan in January 2021 including accelerated amortization of prior debt issuance and discount costs. (h) Represents professional fees related to litigation associated with our EO sterilization facilities and other related professional fees. See Note 16, “Commitments and Contingencies” . (i) Represents non-cash accretion of asset retirement obligations related to Co-60 and gamma processing facilities, which are based on estimated site remediation costs for any future decommissioning of these facilities (without regard for whether the decommissioning services would be performed by employees of Nordion, instead of by a third party) and are accreted over the life of the asset. (j) Represents non-recurring costs associated with the COVID-19 pandemic, including incremental costs to implement workplace health and safety measures.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates – In preparing our consolidated financial statements in conformity with U.S. Generally Accepted Accounting Principles ("GAAP"), we make estimates and assumptions that affect the amounts reported and the accompanying notes. We regularly evaluate the estimates and assumptions used and revise them as new information becomes available. Actual results may vary from those estimates.
ASU’s Issued But Not Yet Adopted	ASU’s Issued But Not Yet Adopted Under the Jumpstart Our Business Startups Act of 2012, emerging growth companies can delay adopting new or revised accounting standards until such time as those standards apply to private companies. As an emerging growth company, we have elected to take advantage of the extended transition period for complying with new or revised accounting standards until those standards would otherwise apply to private companies or at which time we conclude it is appropriate to avail ourselves of early adoption provisions of applicable standards. As a result, our results of operations and financial statements may not be comparable to the results of operations and financial statements of other companies who have adopted the new or revised accounting standards. In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses (“ASU 2016-13”): Measurement of Credit Losses on Financial Instruments, and subsequently issued additional guidance that modified ASU 2016-13. The standard requires an entity to change its accounting approach in determining impairment of certain financial instruments, including trade receivables, from an “incurred loss” to a “current expected credit loss” model. We intend to adopt the standard as of January 1, 2022. We are currently assessing the effect that ASU 2016-13 will have on our financial position, results of operations, and disclosures. In March 2019, the FASB issued ASU 2019-12 - Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The standard simplifies the accounting for income taxes and makes a number of changes meant to add or clarify guidance on accounting for income taxes. This update is effective for annual financial statement periods beginning after March 15, 2021 and interim periods beginning after March 15, 2022, with early adoption permitted in any interim period for which financial statements have not yet been filed. We are currently assessing the effect that ASU 2019-12 will have on our financial position, results of operations, and disclosures.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table shows disaggregated net revenues from contracts with external customers by timing of revenue and by segment for the three months ended March 31, 2021 and 2020: (thousands of U.S. dollars) Three Months Ended March 31, 2021 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 131,151 $ 25,918 $ — $ 157,069 Over time — — 55,079 55,079 Total $ 131,151 $ 25,918 $ 55,079 $ 212,148 (thousands of U.S. dollars) Three Months Ended March 31, 2020 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 117,280 $ 23,625 $ — $ 140,905 Over time — — 47,295 47,295 Total $ 117,280 $ 23,625 $ 47,295 $ 188,200

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The preliminary estimated fair value of the underlying acquired assets and assumed liabilities of the Iotron acquisition and the measurement period adjustments recognized during the three months ended March 31, 2021, were as follows: (thousands of U.S. dollars) Allocation of purchase price to the fair value of net assets acquired (net of cash acquired): Amount recognized as of December 31, 2020 Measurement Period Adjustments Amount recognized as of March 31, 2021 Goodwill $ 69,046 $ (17,142) $ 51,904 Intangibles 16,427 26,273 42,700 Property, plant, and equipment 13,812 4,346 18,158 Working capital, net 1,115 2 1,117 Investment in unconsolidated affiliate 12,881 (4,181) 8,700 Assumed long-term liabilities (2,248) — (2,248) Other assets/liabilities, net (5,846) (9,298) (15,144) Total estimated purchase price $ 105,187 $ — $ 105,187
Business Acquisition, Pro Forma Information	(thousands of U.S. dollars) Three Months Ended March 31, 2020 Net revenues $ 194,402 Net loss (889)

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted primarily of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Raw materials and supplies $ 29,512 $ 29,114 Work-in-process 1,371 846 Finished goods 2,617 4,256 33,500 34,216 Reserve for excess and obsolete inventory (125) (123) Inventories, net $ 33,375 $ 34,093

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Deferred Costs, Capitalized, Prepaid, and Other Assets	Prepaid expenses and other current assets consisted primarily of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Prepaid taxes $ 25,356 $ 22,883 Prepaid business insurance 7,421 10,403 Prepaid rent 1,212 1,170 Customer contract assets 14,133 12,670 Insurance and indemnification receivables 2,751 2,751 Current deposits 797 673 Prepaid maintenance contracts 432 404 Value added tax receivable 1,385 2,094 Prepaid software licensing 1,299 1,181 Stock supplies 3,210 2,715 Other 11,762 8,020 Prepaid expenses and other current assets $ 69,758 $ 64,964

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes to goodwill during the three months ended March 31, 2021 were as follows: (thousands of U.S. dollars) Sterigenics Nordion Nelson Labs Total Goodwill at December 31, 2020 $ 683,481 $ 287,932 $ 144,523 $ 1,115,936 BioScience acquisition — — 8,435 8,435 Iotron acquisition measurement period adjustments (17,142) — — (17,142) Changes due to foreign currency exchange rates (2,252) 3,408 (1,657) (501) Goodwill at March 31, 2021 $ 664,087 $ 291,340 $ 151,301 $ 1,106,728
Schedule of Acquired Finite-Lived Intangible Assets	Other intangible assets consisted of the following: (thousands of U.S. dollars) Gross Carrying Amount Accumulated Amortization As of March 31, 2021 Finite-lived intangible assets Customer relationships $ 662,509 $ 322,685 Proprietary technology 89,604 39,707 Trade names 142 100 Land-use rights 9,454 1,364 Sealed source and supply agreements 243,660 98,237 Other 5,675 1,138 Total finite-lived intangible assets 1,011,044 463,231 Indefinite-lived intangible assets Regulatory licenses and other (a) 82,807 — Trade names / trademarks 25,952 — Total indefinite-lived intangible assets 108,759 — Total $ 1,119,803 $ 463,231 As of December 31, 2020 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 634,454 $ 309,428 Proprietary technology 90,964 38,075 Trade names 156 105 Land-use rights 9,489 1,311 Sealed source and supply agreements 240,791 92,953 Other 1,937 519 Total finite-lived intangible assets 977,791 442,391 Indefinite-lived intangible assets Regulatory licenses and other (a) 81,832 — Trade names / trademarks 26,134 — Total indefinite-lived intangible assets 107,966 — Total $ 1,085,757 $ 442,391 (a) Includes certain transportation certifications, a class 1B nuclear license and other intangibles related to obtaining such licensure. These assets are considered indefinite-lived as the decision for renewal by the Canadian Nuclear Safety Commission is highly based on a licensee’s previous assessments, reported incidents, and annual compliance and inspection results. New applications for license can take a significant amount of time and cost; whereas an existing licensee with a historical record of compliance and current operating conditions more than likely ensures renewal for another 10 years license period as Nordion has demonstrated over its 70 years of history.
Schedule of Acquired Indefinite-lived Intangible Assets	Other intangible assets consisted of the following: (thousands of U.S. dollars) Gross Carrying Amount Accumulated Amortization As of March 31, 2021 Finite-lived intangible assets Customer relationships $ 662,509 $ 322,685 Proprietary technology 89,604 39,707 Trade names 142 100 Land-use rights 9,454 1,364 Sealed source and supply agreements 243,660 98,237 Other 5,675 1,138 Total finite-lived intangible assets 1,011,044 463,231 Indefinite-lived intangible assets Regulatory licenses and other (a) 82,807 — Trade names / trademarks 25,952 — Total indefinite-lived intangible assets 108,759 — Total $ 1,119,803 $ 463,231 As of December 31, 2020 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 634,454 $ 309,428 Proprietary technology 90,964 38,075 Trade names 156 105 Land-use rights 9,489 1,311 Sealed source and supply agreements 240,791 92,953 Other 1,937 519 Total finite-lived intangible assets 977,791 442,391 Indefinite-lived intangible assets Regulatory licenses and other (a) 81,832 — Trade names / trademarks 26,134 — Total indefinite-lived intangible assets 107,966 — Total $ 1,085,757 $ 442,391 (a) Includes certain transportation certifications, a class 1B nuclear license and other intangibles related to obtaining such licensure. These assets are considered indefinite-lived as the decision for renewal by the Canadian Nuclear Safety Commission is highly based on a licensee’s previous assessments, reported incidents, and annual compliance and inspection results. New applications for license can take a significant amount of time and cost; whereas an existing licensee with a historical record of compliance and current operating conditions more than likely ensures renewal for another 10 years license period as Nordion has demonstrated over its 70 years of history.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated aggregate amortization expense for finite-lived intangible assets for each of the next five years and thereafter is as follows: (thousands of U.S. dollars) For the remainder of 2021 $ 65,889 2022 80,665 2023 80,659 2024 79,882 2025 41,982 Thereafter 198,736 Total $ 547,813

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Accrued employee compensation $ 27,651 $ 34,760 Legal reserves 2,751 2,751 Accrued interest expense 764 186 Embedded derivatives 229 670 Professional fees 13,744 12,686 Accrued utilities 2,397 1,864 Insurance accrual 1,886 1,255 Accrued taxes 3,332 2,599 Other 3,619 3,747 Accrued liabilities $ 56,373 $ 60,518

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following: (thousands of U.S. dollars) March 31, 2021 December 31, 2020 Term loan, due 2026 $ 1,763,100 $ 1,763,100 Senior notes, due 2026 100,000 100,000 Other long-term debt 1,059 450 Total long-term debt 1,864,159 1,863,550 Less unamortized debt issuance costs and debt discounts (26,579) (38,761) Total long-term debt, less debt issuance costs and debt discounts $ 1,837,580 $ 1,824,789
Schedule of Maturities of Long-term Debt	Aggregate maturities of the Company’s long-term debt, excluding debt discounts, as of March 31, 2021, are as follows: (thousands of U.S. dollars) 2021 $ — 2022 609 2023 450 2024 — 2025 — Thereafter 1,863,100 Total $ 1,864,159

Employee Benefits (Tables)

Employee Benefits (Tables)	3 Months Ended
	Mar. 31, 2021
Postemployment Benefits [Abstract]
Schedule of Net Benefit Costs	The components of net periodic pension cost for the defined benefit plans for the three months ended March 31, 2021 and 2020 were as follows: Three Months Ended March 31, (thousands of U.S. dollars) 2021 2020 Service cost $ 298 $ 276 Interest cost 1,613 2,007 Expected return on plan assets (3,557) (3,599) Amortization of net actuarial loss 267 197 Net periodic benefit $ (1,379) $ (1,119) Three Months Ended March 31, (thousands of U.S. dollars) 2021 2020 Service cost $ 7 $ 7 Interest cost 59 73 Amortization of net actuarial (gain) loss 8 13 Net periodic benefit cost $ 74 $ 93

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in our accumulated other comprehensive income (loss) balances, net of applicable tax, were as follows: (thousands of U.S. dollars) Defined Benefit Plans Foreign Currency Translation Interest Rate Swaps Total Beginning balance – January 1, 2021 $ (44,143) $ (49,699) $ — $ (93,842) Other comprehensive income (loss) before reclassifications (524) (3,071) — (3,595) Amounts reclassified from accumulated other comprehensive income (loss) 275 (a) — — 275 Net current-period other comprehensive income (loss) (249) (3,071) — (3,320) Ending balance – March 31, 2021 $ (44,392) $ (52,770) $ — $ (97,162) Beginning balance – January 1, 2020 $ (27,113) $ (67,453) $ 179 $ (94,387) Other comprehensive income (loss) before reclassifications 2,207 (72,967) (3,292) (74,052) Amounts reclassified from accumulated other comprehensive income (loss) — — (187) (b) (187) Net current-period other comprehensive income (loss) 2,207 (72,967) (3,479) (74,239) Ending balance – March 31, 2020 $ (24,906) $ (140,420) $ (3,300) $ (168,626) (a) For defined benefit pension plans, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Other income, net” within the Consolidated Statements of Operations and Comprehensive Income (Loss). (b) For interest rate swaps, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Interest expense, net” within the Consolidated Statements of Operations and Comprehensive Income (Loss).

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Restricted Stock Activity	A summary of the activity for the three months ended March 31, 2021 related to the restricted stock awards distributed to the Company service providers in respect of the pre-IPO awards (Class B-1 and B-2 Units) is presented below: Restricted Stock - Pre- IPO B-1 Restricted Stock - Pre- IPO B-2 Unvested at December 31, 2020 2,201,239 2,323,333 Forfeited (43,361) (254,839) Vested (228,862) — Unvested at March 31, 2021 1,929,016 2,068,494 Number of Shares Weighted- average Grant Date Fair Value Unvested at December 31, 2020 771,276 $ 23.00 Granted 10,851 26.03 Forfeited (24,999) 23.00 Vested — — Unvested at March 31, 2021 757,128 $ 23.05
Schedule of Stock Option Activity	The following table summarizes our stock option activity: Number of Shares Weighted- average Exercise Price At December 31, 2020 2,389,258 $ 23.00 Granted 20,407 26.26 Forfeited (9,316) 23.00 Exercised — — At March 31, 2021 2,400,349 $ 23.03

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Our basic and diluted earnings per common share are calculated as follows: Three Months Ended in thousands of U.S. dollars and share amounts (except per share amounts) March 31, March 31, Earnings (Loss): Net income (loss) $ 11,065 $ (1,986) Less: Net income (loss) attributable to noncontrolling interests 223 (22) Less: Allocation to participating securities 157 — Net income (loss) attributable to Sotera Health Company common shareholders $ 10,685 $ (1,964) Weighted Average Common Shares: Weighted-average common shares outstanding - basic 278,827 232,400 Dilutive effect of potential common shares 141 — Weighted-average common shares outstanding - diluted (a) 278,968 232,400 Earnings (loss) per Common Share: Net income (loss) attributable to Sotera Health Company common shareholders - basic $ 0.04 $ (0.01) Net income (loss) attributable to Sotera Health Company common shareholders - diluted 0.04 (0.01) (a) A n additional 2,400,349 and 3,645 equivalent shares related to stock options and RSUs, respectively, issued in connection with the 2020 Omnibus Incentive Plan were excluded from the calculation of diluted weighted average common shares outstanding for the three months ended March 31, 2021 as they were anti-dilutive . For the three months ended March 31, 2020, there were no potentially dilutive common shares outstanding.

Financial Instruments and Fin_2

Financial Instruments and Financial Risk (Tables)	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following table provides a summary of the notional and fair values of our derivative instruments: March 31, 2021 December 31, 2020 (in U.S. Dollars; notional in millions, fair value in thousands) Fair Value Fair Value Notional Derivative Derivative Notional Derivative Derivative Derivatives not designated as hedging instruments Interest rate caps $ 2,500.0 $ 9 $ — $ 1,500.0 $ 7 $ — Embedded derivatives 77.7 (a) 403 229 83.3 — 670 Total $ 2,577.7 $ 412 $ 229 $ 1,583.3 $ 7 $ 670 (a) Represents the total notional amounts for certain of the Company’s supply and sales contracts accounted for as embedded derivatives.
Schedule of Derivative Instruments, Gain (Loss)	The following tables summarize the activities of our derivative instruments for the periods presented, and the line item they are recorded in in the Consolidated Statements of Operations and Comprehensive Income (Loss): (thousands of U.S. dollars) Three Months March 31, 2021 2020 Unrealized loss on interest rate caps recorded in interest expense, net $ 90 $ — Unrealized (gain) loss on embedded derivatives recorded in other income, net (853) 4,819 Realized gain on foreign currency forward contracts recorded in foreign exchange (gain) loss (2,374) —
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table discloses the fair value of our financial assets and liabilities: As of March 31, 2021 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives not designated as hedging instruments (a) Interest rate caps $ 9 $ — $ 9 $ — Embedded derivative assets 403 — 403 — Embedded derivative liabilities (229) — (229) — Long-Term Debt (b) Term loan, due 2026 1,740,071 — 1,760,896 — Senior notes, due 2026 96,458 — 97,587 — Other long-term debt 1,051 — 1,051 — Finance Lease Obligations (with current portion) (c) 34,540 — 34,540 — As of December 31, 2020 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives not designated as hedging instruments (a) Interest rate caps $ 7 $ — $ 7 $ — Embedded derivative liabilities (670) — (670) — Long-Term Debt (b) Term loan, due 2026 1,728,018 — 1,772,180 — Senior notes, due 2026 96,329 — 99,863 — Other long-term debt 442 — 442 — Finance Lease Obligations (with current portion) (c) 36,112 — 36,112 — (a) Derivatives that are not designated as hedging instruments are measured at fair value with gains or losses recognized immediately in the Consolidated Statements of Operations and Comprehensive Income (Loss). Interest rate caps are valued using pricing models that incorporate observable market inputs including interest rate and yield curves. Embedded derivatives are valued using internally developed models that rely on observable market inputs including foreign currency forward curves. (b) Carrying amounts of long-term debt instruments are reported net of discounts and debt issuance costs. The estimated fair value of these instruments is based on information provided by the agent under the Company’s senior secured credit facility. Fair value approximates carrying value for “Other long-term debt.” (c) Fair value approximates carrying value.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	(thousands of U.S. dollars) Three Months Ended March 31, 2021 Sterigenics Nordion Nelson Labs Consolidated Net revenues (a) $ 131,151 $ 25,918 $ 55,079 $ 212,148 Segment income (b) 68,461 13,786 23,070 105,317 Capital expenditures 19,514 489 939 20,942 Three Months Ended March 31, 2020 Sterigenics Nordion Nelson Labs Consolidated Net revenues (a) $ 117,280 $ 23,625 $ 47,295 $ 188,200 Segment income (b) 61,091 13,022 17,770 91,883 Capital expenditures 10,940 1,234 815 12,989 (a) Revenues are reported net of intersegment sales. Our Nordion segment recognized $10.5 million and $10.9 million in revenues from sales to our Sterigenics segment for the three months ended March 31, 2021 and 2020, respectively, that is not reflected in net revenues in the table above. Intersegment sales for Sterigenics and Nelson Labs are immaterial for both periods.
Schedule of Reconciliation of Operating Profit (Loss) from Segments to Consolidated	A reconciliation of segment income to consolidated income (loss) before taxes is as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2021 2020 Segment income $ 105,317 $ 91,883 Less adjustments: Interest expense, net 21,282 56,562 Depreciation and amortization (a) 37,661 36,023 Share-based compensation (b) 3,449 1,725 (Gain) loss on foreign currency and embedded derivatives (c) (336) 4,267 Acquisition and divestiture related charges, net (d) (185) 994 Business optimization project expenses (e) 261 1,049 Plant closure expenses (f) 542 771 Loss on extinguishment of debt (g) 14,312 — Professional services relating to EO sterilization facilities (h) 13,399 4,146 Accretion of asset retirement obligation (i) 551 490 COVID-19 expenses (j) 299 76 Consolidated income (loss) before taxes $ 14,082 $ (14,220) (a) Includes depreciation of Co-60 held at gamma irradiation sites. (b) Represents non-cash share-based compensation expense. (c) Represents the effects of (i) fluctuations in foreign currency exchange rates, primarily related to remeasurement of intercompany loans denominated in currencies other than subsidiaries’ functional currencies, and (ii) non-cash mark-to-fair value of embedded derivatives relating to certain customer and supply contracts at Nordion. (d) Represents (i) certain direct and incremental costs related to the acquisitions of BioScience in 2021, Iotron in July 2020 and Nelson Labs Fairfield in 2018 (including the first quarter 2021 gain on the mandatorily redeemable noncontrolling interest as described in Note 4, “Acquisitions”), and certain related integration efforts as a result of those acquisitions, (ii) the earnings impact of fair value adjustments (excluding those recognized within amortization expense) resulting from the businesses acquired, and (iii) transition services income and non-cash deferred lease income associated with the terms of the divestiture of the Medical Isotopes business in 2018. (e) Represents professional fees, contract termination and exit costs, severance and other payroll costs, and other costs associated with business optimization and cost savings projects relating to the integration of Nelson Labs, the Sotera Health rebranding, operating structure realignment and other process enhancement projects. (f) Represents professional fees, severance and other payroll costs, and other costs including ongoing lease and utility expenses associated with the closure of the Willowbrook, Illinois facility. (g) Represents expenses incurred in connection with the repricing of our Term Loan in January 2021 including accelerated amortization of prior debt issuance and discount costs. (h) Represents professional fees related to litigation associated with our EO sterilization facilities and other related professional fees. See Note 16, “Commitments and Contingencies” . (i) Represents non-cash accretion of asset retirement obligations related to Co-60 and gamma processing facilities, which are based on estimated site remediation costs for any future decommissioning of these facilities (without regard for whether the decommissioning services would be performed by employees of Nordion, instead of by a third party) and are accreted over the life of the asset. (j) Represents non-recurring costs associated with the COVID-19 pandemic, including incremental costs to implement workplace health and safety measures.

Basis of Presentation (Details)

Basis of Presentation (Details) $ in Millions	Mar. 11, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021segmentsubsidiary	Jul. 31, 2020	Aug. 31, 2018
Accounting Policies [Abstract]
Number of operating segments | segment			3
Number of reportable segments | segment			3
Unnamed E-Beam Joint Venture
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership percentage				60.00%
Nelson Fairfield
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Interest acquired	15.00%				85.00%
Purchase price | $	$ 12.4
China
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of subsidiaries with non-controlling interest | subsidiary			2
China | Forecast
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Purchase price | $		$ 8.6
China | Subsidiary One
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership percentage			15.00%
China | Subsidiary One | Nelson Fairfield
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Interest acquired			15.00%
China | Subsidiary Two
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership percentage			33.00%
Percent of purchase of interest			33.00%

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total net revenues	$ 212,148	$ 188,200
Customer contract assets	14,133		$ 12,670
Deferred revenue	5,958		$ 6,056
Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	157,069	140,905
Over time
Disaggregation of Revenue [Line Items]
Total net revenues	55,079	47,295
Sterigenics
Disaggregation of Revenue [Line Items]
Total net revenues	131,151	117,280
Sterigenics | Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	131,151	117,280
Sterigenics | Over time
Disaggregation of Revenue [Line Items]
Total net revenues	0	0
Nordion
Disaggregation of Revenue [Line Items]
Total net revenues	25,918	23,625
Nordion | Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	25,918	23,625
Nordion | Over time
Disaggregation of Revenue [Line Items]
Total net revenues	0	0
Nelson Labs
Disaggregation of Revenue [Line Items]
Total net revenues	55,079	47,295
Nelson Labs | Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	0	0
Nelson Labs | Over time
Disaggregation of Revenue [Line Items]
Total net revenues	$ 55,079	$ 47,295

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($) $ in Thousands	Mar. 11, 2021	Mar. 08, 2021	Jul. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Aug. 31, 2018
Business Acquisition [Line Items]
Payments to acquire businesses				$ 13,152	$ 0
Goodwill				1,106,728		$ 1,115,936
Unnamed E-Beam Joint Venture
Business Acquisition [Line Items]
Ownership percentage			60.00%
BioScience
Business Acquisition [Line Items]
Payments to acquire businesses		$ 13,200
Cash acquired		800
Liabilities incurred		1,900
Goodwill		$ 8,400
Nelson Fairfield
Business Acquisition [Line Items]
Interest acquired	15.00%						85.00%
Purchase price	$ 12,400
Step acquisition, gain	$ 1,200
Mandatorily redeemable noncontrolling interest						13,600
Iotron
Business Acquisition [Line Items]
Goodwill				$ 51,904		$ 69,046
Purchase price			$ 105,200
Goodwill acquired			51,900
Goodwill deductible amount			$ 51,900
Acquisition related costs					$ 1,000
Iotron | Minimum
Business Acquisition [Line Items]
Estimated useful life			5 years
Iotron | Maximum
Business Acquisition [Line Items]
Estimated useful life			15 years
Iotron | First Lien Notes due 2026
Business Acquisition [Line Items]
Proceeds from issuance of debt			$ 100,000
Iotron | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles			39,100
Iotron | Employee Non-compete Agreements
Business Acquisition [Line Items]
Finite-lived intangibles			$ 3,600

Acquisitions - Purchase Price A

Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 1,106,728	$ 1,115,936
Iotron
Business Acquisition [Line Items]
Goodwill	51,904	69,046
Intangibles	42,700	16,427
Property, plant, and equipment	18,158	13,812
Working capital, net	1,117	1,115
Investment in unconsolidated affiliate	8,700	12,881
Assumed long-term liabilities	(2,248)	(2,248)
Working capital, net	(15,144)	(5,846)
Total estimated purchase price	105,187	$ 105,187
Measurement Period Adjustments
Goodwill	(17,142)
Intangibles	26,273
Property, plant, and equipment	4,346
Working capital, net	2
Investment in unconsolidated affiliate	(4,181)
Assumed long-term liabilities	0
Working capital, net	(9,298)
Total estimated purchase price	$ 0

Acquisitions - Pro Forma Inform

Acquisitions - Pro Forma Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Business Combinations [Abstract]
Net revenues	$ 194,402
Net loss	$ (889)

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 29,512	$ 29,114
Work-in-process	1,371	846
Finished goods	2,617	4,256
Inventories, gross	33,500	34,216
Reserve for excess and obsolete inventory	(125)	(123)
Inventories, net	$ 33,375	$ 34,093

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid taxes	$ 25,356	$ 22,883
Prepaid business insurance	7,421	10,403
Prepaid rent	1,212	1,170
Customer contract assets	14,133	12,670
Insurance and indemnification receivables	2,751	2,751
Current deposits	797	673
Prepaid maintenance contracts	432	404
Value added tax receivable	1,385	2,094
Prepaid software licensing	1,299	1,181
Stock supplies	3,210	2,715
Other	11,762	8,020
Prepaid expenses and other current assets	$ 69,758	$ 64,964

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 1,115,936
Changes due to foreign currency exchange rates	(501)
Ending balance	1,106,728
BioScience
Goodwill [Roll Forward]
Adjustments	8,435
Iotron
Goodwill [Roll Forward]
Beginning balance	69,046
Adjustments	(17,142)
Ending balance	51,904
Sterigenics
Goodwill [Roll Forward]
Beginning balance	683,481
Changes due to foreign currency exchange rates	(2,252)
Ending balance	664,087
Sterigenics | BioScience
Goodwill [Roll Forward]
Adjustments	0
Sterigenics | Iotron
Goodwill [Roll Forward]
Adjustments	(17,142)
Nordion
Goodwill [Roll Forward]
Beginning balance	287,932
Changes due to foreign currency exchange rates	3,408
Ending balance	291,340
Nordion | BioScience
Goodwill [Roll Forward]
Adjustments	0
Nordion | Iotron
Goodwill [Roll Forward]
Adjustments	0
Nelson Labs
Goodwill [Roll Forward]
Beginning balance	144,523
Changes due to foreign currency exchange rates	(1,657)
Ending balance	151,301
Nelson Labs | BioScience
Goodwill [Roll Forward]
Adjustments	8,435
Nelson Labs | Iotron
Goodwill [Roll Forward]
Adjustments	$ 0

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,011,044	$ 977,791
Accumulated Amortization	463,231	442,391
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	108,759	107,966
Total	1,119,803	1,085,757
Regulatory licenses and other
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 82,807	81,832
Renewal term	10 years
Trade names / trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 25,952	26,134
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	662,509	634,454
Accumulated Amortization	322,685	309,428
Proprietary technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	89,604	90,964
Accumulated Amortization	39,707	38,075
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	142	156
Accumulated Amortization	100	105
Land-use rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	9,454	9,489
Accumulated Amortization	1,364	1,311
Sealed source and supply agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	243,660	240,791
Accumulated Amortization	98,237	92,953
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,675	1,937
Accumulated Amortization	$ 1,138	$ 519

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 22,282	$ 19,913
Finite-lived intangible assets, remaining amortization period	10 years
Other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 22,300	19,900
Other | Cost of Revenue
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	5,800	5,300
Other | Selling, General and Administrative Expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 16,500	$ 14,600

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2021USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
For the remainder of 2021	$ 65,889
2022	80,665
2023	80,659
2024	79,882
2025	41,982
Thereafter	198,736
Total	$ 547,813

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Payables and Accruals [Abstract]
Accrued employee compensation	$ 27,651		$ 34,760
Legal reserves	2,751		2,751
Accrued interest expense	764		186
Embedded derivatives	229		670
Professional fees	13,744		12,686
Accrued utilities	2,397		1,864
Insurance accrual	1,886		1,255
Accrued taxes	3,332		2,599
Other	3,619		3,747
Accrued liabilities	$ 56,373	$ 60,518	$ 60,518

Long-Term Debt - Schedule of De

Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total long-term debt	$ 1,864,159	$ 1,863,550
Less unamortized debt issuance costs and debt discounts	(26,579)	(38,761)
Long-term Debt	1,864,159
Total long-term debt, less debt issuance costs and debt discounts	1,837,580	1,824,789
Term Loan | Term loan, due 2026
Debt Instrument [Line Items]
Total long-term debt	1,763,100	1,763,100
Senior Notes | Senior notes, due 2026
Debt Instrument [Line Items]
Total long-term debt	100,000	100,000
Other long-term debt
Debt Instrument [Line Items]
Total long-term debt	$ 1,059	$ 450

Long-Term Debt - Senior Secured

Long-Term Debt - Senior Secured Credit Facilities (Details) - USD ($)	Mar. 26, 2021	Jan. 20, 2021	Jan. 19, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 17, 2020	Dec. 16, 2020	Jul. 31, 2020
Debt Instrument [Line Items]
Total long-term debt				$ 1,864,159,000		$ 1,863,550,000
Senior Secured Credit Facilities | Term Loan
Debt Instrument [Line Items]
Debt issuance costs				3,100,000		3,400,000
Debt discount				20,000,000		31,600,000
Term loan, due 2026 | Term Loan
Debt Instrument [Line Items]
Total long-term debt				$ 1,763,100,000		1,763,100,000
Weighted average interest rate				3.73%	6.18%
Effective reduction in current interest rates		2.25%
Term loan, due 2026 | Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		2.75%	4.50%
LIBOR floor		0.50%	1.00%
Write-off of unamortized debt issuance costs and debt discounts		$ 11,300,000
Additional expense		$ 2,900,000
First Lien Notes due 2026
Debt Instrument [Line Items]
Debt discount				$ 2,700,000		2,800,000
First Lien Notes due 2026 | Secured Debt
Debt Instrument [Line Items]
Weighted average interest rate				7.00%
LIBOR floor									1.00%
First Lien Notes due 2026 | Secured Debt | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%			6.00%
First Lien Notes due 2026 | Secured Debt | Alternative Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
First Lien Notes due 2026 | Secured Debt | Eurodollar | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	3.50%
First Lien Notes due 2026 | Secured Debt | Eurodollar | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	4.00%
Revolving Credit Facility | Senior Secured Credit Facilities
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 347,500,000	$ 190,000,000
Total long-term debt				$ 0	$ 50,000,000	$ 0
Weighted average interest rate					5.00%
Letters of credit outstanding, amount				65,800,000
Unused borrowing capacity				$ 281,700,000
Revolving Credit Facility | Senior Secured Credit Facilities | Alternative Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%
Revolving Credit Facility | Senior Secured Credit Facilities | Alternative Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%

Long-Term Debt - First Lien Not

Long-Term Debt - First Lien Notes (Details) - First Lien Notes due 2026 - USD ($)	Mar. 26, 2021	Mar. 31, 2021	Dec. 31, 2020	Jul. 31, 2020
Debt Instrument [Line Items]
Capitalized debt issuance costs		$ 800,000	$ 900,000
Debt discount		$ 2,700,000	$ 2,800,000
Secured Debt
Debt Instrument [Line Items]
Face amount				$ 100,000,000
LIBOR floor				1.00%
Weighted average interest rate		7.00%
Secured Debt | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%	6.00%

Long-Term Debt - Repayments of

Long-Term Debt - Repayments of Debt (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 24, 2020	Nov. 30, 2020	Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Unamortized debt issuance costs and debt discounts					$ 26,579	$ 38,761
Second Lien Notes
Debt Instrument [Line Items]
Write-off of debt premium				$ 15,400
Term Loan and Second Lien Notes
Debt Instrument [Line Items]
Unamortized debt issuance costs and debt discounts			$ 28,900	$ 28,900
Term Loan | Second Lien Notes
Debt Instrument [Line Items]
Extinguishment of debt			$ 770,000
Term Loan | Term loan, due 2026
Debt Instrument [Line Items]
Extinguishment of debt		$ 341,000
Common Stock | Officer
Debt Instrument [Line Items]
Stock Repurchased During Period, Shares	1,568,445
IPO | Common Stock
Debt Instrument [Line Items]
Number of shares sold (in shares)	53,590,000
Sale of stock (in dollars per share)	$ 23
Number of additional shares to be repurchased (in shares)	6,990,000
Consideration received	$ 1,200,000

Long-Term Debt - Aggregate Matu

Long-Term Debt - Aggregate Maturities (Details) $ in Thousands	Mar. 31, 2021USD ($)
Debt Disclosure [Abstract]
2021	$ 0
2022	609
2023	450
2024	0
2025	0
Thereafter	1,863,100
Total	$ 1,864,159

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate	21.40%	(86.00%)
Limitation on deductibility of interest expense	50.00%		30.00%
Current income tax benefit	$ 9,100
Reversal of valuation allowance	$ 5,600

Employee Benefits - Net Periodi

Employee Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 298	$ 276
Interest cost	1,613	2,007
Expected return on plan assets	(3,557)	(3,599)
Amortization of net actuarial loss	267	197
Net periodic benefit cost	(1,379)	(1,119)
Other benefits plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	7
Interest cost	59	73
Amortization of net actuarial loss	8	13
Net periodic benefit cost	$ 74	$ 93

Employee Benefits - Additional

Employee Benefits - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Postemployment Benefits [Abstract]
Expect funding requirements in each of the next five years	$ 2,800
Defined benefit pension plan
Defined Benefit Plan Disclosure [Line Items]
Letters of credit outstanding, amount	$ 42,600	$ 41,300
Defined benefit pension plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Solvency payment as percent of market value	15.00%

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 454,574	$ (641,132)
Balance	465,744	(715,632)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(93,842)	(94,387)
Other comprehensive income (loss) before reclassifications	(3,595)	(74,052)
Amounts reclassified from accumulated other comprehensive income (loss)	275	(187)
Net current-period other comprehensive income (loss)	(3,320)	(74,239)
Balance	(97,162)	(168,626)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(44,143)	(27,113)
Other comprehensive income (loss) before reclassifications	(524)	2,207
Amounts reclassified from accumulated other comprehensive income (loss)	275	0
Net current-period other comprehensive income (loss)	(249)	2,207
Balance	(44,392)	(24,906)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(49,699)	(67,453)
Other comprehensive income (loss) before reclassifications	(3,071)	(72,967)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net current-period other comprehensive income (loss)	(3,071)	(72,967)
Balance	(52,770)	(140,420)
Interest Rate Swaps
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	0	179
Other comprehensive income (loss) before reclassifications	0	(3,292)
Amounts reclassified from accumulated other comprehensive income (loss)	0	(187)
Net current-period other comprehensive income (loss)	0	(3,479)
Balance	$ 0	$ (3,300)

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 2,800
Restricted Stock | Pre-IPO B-1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
Share-based compensation expense	$ 700	$ 1,700
Restricted Stock | Pre-IPO B-1 | Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20.00%
Restricted Stock | Pre-IPO B-1 | Year Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20.00%
Restricted Stock | Pre-IPO B-1 | Year Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20.00%
Restricted Stock | Pre-IPO B-1 | Year Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20.00%
Restricted Stock | Pre-IPO B-1 | Year Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20.00%
Restricted Stock | Pre-IPO B-2 | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash proceeds to sponsors, ratio to invested capital	250.00%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Contractual term	10 years
Stock Options | 2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,300
RSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
RSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
RSUs | 2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,500

Share-Based Compensation - Pre-

Share-Based Compensation - Pre-IPO Awards (Class B-1 and B-2) (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2021shares
Pre-IPO B-1
Number of Shares
Beginning balance (in shares)	2,201,239
Forfeited (in shares)	(43,361)
Vested (in shares)	(228,862)
Ending balance (in shares)	1,929,016
Pre-IPO B-2
Number of Shares
Beginning balance (in shares)	2,323,333
Forfeited (in shares)	(254,839)
Vested (in shares)	0
Ending balance (in shares)	2,068,494

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Options (Details)	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	2,389,258
Granted (in shares) | shares	20,407
Forfeited (in shares) | shares	(9,316)
Exercised (in shares) | shares	0
Ending balance (in shares) | shares	2,400,349
Weighted- average Exercise Price
Beginning balance (in shares) | $ / shares	$ 23
Granted (in dollars per share) | $ / shares	26.26
Forfeited (in dollars per share) | $ / shares	23
Exercised (in dollars per share) | $ / shares	0
Ending balance (in shares) | $ / shares	$ 23.03

Share-Based Compensation - RSUs

Share-Based Compensation - RSUs (Details) - RSUs	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	771,276
Granted (in shares) | shares	10,851
Forfeited (in shares) | shares	(24,999)
Vested (in shares) | shares	0
Ending balance (in shares) | shares	757,128
Weighted- average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 23
Granted (in dollars per share) | $ / shares	26.03
Forfeited (in dollars per share) | $ / shares	23
Vested (in dollars per share) | $ / shares	0
Ending balance (in dollars per share) | $ / shares	$ 23.05

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings (Loss):
Net income (loss)	$ 11,065	$ (1,986)
Less: Net income (loss) attributable to noncontrolling interests	223	(22)
Less: Allocation to participating securities	157	0
Less: Allocation to participating securities	157	0
Net income (loss) attributable to Sotera Health Company common shareholders	10,685	(1,964)
Net income (loss) attributable to Sotera Health Company common shareholders	$ 10,685	$ (1,964)
Weighted Average Common Shares:
Weighted-average common shares outstanding - basic (in shares)	278,827,000	232,400,000
Dilutive effect of potential common shares (in shares)	141,000	0
Weighted-average common shares outstanding - diluted (in shares)	278,968,000	232,400,000
Earnings (loss) per Common Share:
Net income (loss) attributable to Sotera Health Company common shareholders - basic (in dollars per share)	$ 0.04	$ (0.01)
Net income (loss) attributable to Sotera Health Company common shareholders - diluted (in dollars per share)	$ 0.04	$ (0.01)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		0
Stock Options | 2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,400,349
RSUs | 2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	3,645

Commitment and Contingencies (D

Commitment and Contingencies (Details)	Aug. 17, 2020claim	May 19, 2020plaintiff	Mar. 30, 2020USD ($)	Mar. 30, 2020CAD ($)	Oct. 22, 2010USD ($)	May 31, 2020	Mar. 31, 2021USD ($)claim	Mar. 31, 2021plaintiff
Gain Contingencies [Line Items]
Loss contingency, insurance limits per occurrence							$ 10,000,000
Loss contingency, insurance limits							$ 20,000,000
Ethylene Oxide Tort Litigation - Illinois
Gain Contingencies [Line Items]
Number of claims dismissed | claim							2
Ethylene Oxide Tort Litigation - Illinois | Pending Litigation
Gain Contingencies [Line Items]
Number of plaintiffs | plaintiff								835
Ethylene Oxide Tort Litigation – Georgia | Pending Litigation
Gain Contingencies [Line Items]
Number of plaintiffs | plaintiff		53
Number of new claims filed | claim	6
Percent of reduction in residential property value assessment						10.00%
Positive Outcome of Litigation | Nordion v Factory Mutual Insurance Company, 2010 Business Interruption Loss
Gain Contingencies [Line Items]
Damages sought, value					$ 25,000,000
Period of inability					15 months
Amount awarded from other party, before pre-judgment interest			$ 25,000,000
Amount awarded from other party			39,800,000	$ 56,400,000
Costs assessed and awarded in favor			800,000	1,100,000
Disbursements assessed and awarded in favor			$ 100,000	$ 161,863

Financial Instruments and Fin_3

Financial Instruments and Financial Risk - Additional Information (Details)	3 Months Ended
	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2021	Feb. 28, 2021USD ($)instrument	Dec. 31, 2020USD ($)	Jun. 30, 2020USD ($)instrument	Sep. 30, 2019USD ($)instrument	Oct. 31, 2017USD ($)instrument
Derivative [Line Items]
Derivative loss, net of tax recognized in accumulated other comprehensive income (loss)	$ 0	$ (3,479,000)
Allowance for uncollectible accounts	603,000				$ 708,000
Interest Rate Swap
Derivative [Line Items]
Derivative loss, net of tax recognized in accumulated other comprehensive income (loss)		$ 3,500,000
Foreign Currency Forward Contracts
Derivative [Line Items]
Fair value of outstanding contracts	0				0
Derivatives Designated in Hedge Relationships | Interest Rate Swap
Derivative [Line Items]
Number of instruments held | instrument							2
Derivatives Not Designated in Hedge Relationships
Derivative [Line Items]
Notional amount	2,577,700				1,583,300
Derivatives Not Designated in Hedge Relationships | Interest Rate Swap
Derivative [Line Items]
Notional amount							$ 1,000,000,000
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap
Derivative [Line Items]
Number of instruments held | instrument				2
Notional amount	$ 2,500,000			$ 1,000,000,000	$ 1,500,000	$ 1,000,000,000		$ 400,000,000
Option premium				$ 400,000		$ 300,000		$ 600,000
Percent of borrowing limitation due to cash flow exposure								3.00%
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap | LIBOR
Derivative [Line Items]
Variable rate				0.50%		1.00%
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap | LIBOR | Forecast
Derivative [Line Items]
Variable rate			0.50%
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap October 2017
Derivative [Line Items]
Number of instruments held | instrument								2
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap June 2020
Derivative [Line Items]
Number of instruments held | instrument						2
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap
Derivative [Line Items]
Notional amount						$ 500,000,000
Derivatives Not Designated in Hedge Relationships | Interest Rate Cap February 2021
Derivative [Line Items]
Number of instruments amended | instrument				2

Financial Instruments and Fin_4

Financial Instruments and Financial Risk - Derivative Instruments (Details) - Derivatives Not Designated in Hedge Relationships - USD ($)	Mar. 31, 2021	Feb. 28, 2021	Dec. 31, 2020	Jun. 30, 2020	Oct. 31, 2017
Derivative [Line Items]
Notional Amount	$ 2,577,700		$ 1,583,300
Fair Value, Derivative Asset	412,000		7,000
Fair Value, Derivative Liabilities	229,000		670,000
Interest Rate Cap
Derivative [Line Items]
Notional Amount	2,500,000	$ 1,000,000,000	1,500,000	$ 1,000,000,000	$ 400,000,000
Fair Value, Derivative Asset	9,000		7,000
Fair Value, Derivative Liabilities	0		0
Embedded Derivative
Derivative [Line Items]
Notional Amount	77,700		83,300
Fair Value, Derivative Asset	403,000		0
Fair Value, Derivative Liabilities	$ 229,000		$ 670,000

Financial Instruments and Fin_5

Financial Instruments and Financial Risk - Activities of Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest Rate Cap | Interest Expense, Net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss (gain)	$ 90	$ 0
Embedded Derivative | Other Income, Net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss (gain)	(853)	4,819
Foreign Currency Forward Contracts | Foreign Exchange (Gain) Loss
Derivative Instruments, Gain (Loss) [Line Items]
Realized loss	$ (2,374)	$ 0

Financial Instruments and Fin_6

Financial Instruments and Financial Risk - Assets and Liabilities Measured on Recurring Basis (Details) - Derivatives Not Designated in Hedge Relationships - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative asset	$ 412	$ 7
Derivative liabilities	(229)	(670)
Term loan, due 2026 | Fair Value, Level 1
Derivative [Line Items]
Long-term debt	0	0
Term loan, due 2026 | Fair Value, Level 2
Derivative [Line Items]
Long-term debt	1,760,896	1,772,180
Term loan, due 2026 | Fair Value, Level 3
Derivative [Line Items]
Long-term debt	0	0
Senior notes, due 2026 | Fair Value, Level 1
Derivative [Line Items]
Long-term debt	0
Senior notes, due 2026 | Fair Value, Level 2
Derivative [Line Items]
Long-term debt	97,587
Senior notes, due 2026 | Fair Value, Level 3
Derivative [Line Items]
Long-term debt	0
Senior notes, due 2027 | Fair Value, Level 1
Derivative [Line Items]
Long-term debt		0
Senior notes, due 2027 | Fair Value, Level 2
Derivative [Line Items]
Long-term debt		99,863
Senior notes, due 2027 | Fair Value, Level 3
Derivative [Line Items]
Long-term debt		0
Other long-term debt | Fair Value, Level 1
Derivative [Line Items]
Long-term debt	0	0
Other long-term debt | Fair Value, Level 2
Derivative [Line Items]
Long-term debt	1,051	442
Other long-term debt | Fair Value, Level 3
Derivative [Line Items]
Long-term debt	0	0
Finance Lease Obligations (with current portion) | Fair Value, Level 1
Derivative [Line Items]
Long-term debt	0	0
Finance Lease Obligations (with current portion) | Fair Value, Level 2
Derivative [Line Items]
Long-term debt	34,540	36,112
Finance Lease Obligations (with current portion) | Fair Value, Level 3
Derivative [Line Items]
Long-term debt	0	0
Interest Rate Cap
Derivative [Line Items]
Derivative asset	9	7
Derivative liabilities	0	0
Interest Rate Cap | Fair Value, Level 1
Derivative [Line Items]
Derivative asset	0	0
Interest Rate Cap | Fair Value, Level 2
Derivative [Line Items]
Derivative asset	9	7
Interest Rate Cap | Fair Value, Level 3
Derivative [Line Items]
Derivative asset	0	0
Embedded Derivative
Derivative [Line Items]
Derivative asset	403	0
Derivative liabilities	(229)	(670)
Embedded Derivative | Fair Value, Level 1
Derivative [Line Items]
Derivative asset	0
Derivative liabilities	0	0
Embedded Derivative | Fair Value, Level 2
Derivative [Line Items]
Derivative asset	403
Derivative liabilities	(229)	(670)
Embedded Derivative | Fair Value, Level 3
Derivative [Line Items]
Derivative asset	0
Derivative liabilities	0	0
Carrying Amount | Term loan, due 2026
Derivative [Line Items]
Long-term debt	1,740,071	1,728,018
Carrying Amount | Senior notes, due 2026
Derivative [Line Items]
Long-term debt	96,458
Carrying Amount | Senior notes, due 2027
Derivative [Line Items]
Long-term debt		96,329
Carrying Amount | Other long-term debt
Derivative [Line Items]
Long-term debt	1,051	442
Carrying Amount | Finance Lease Obligations (with current portion)
Derivative [Line Items]
Long-term debt	34,540	36,112
Carrying Amount | Interest Rate Cap
Derivative [Line Items]
Derivative asset	9	7
Carrying Amount | Embedded Derivative
Derivative [Line Items]
Derivative asset	403
Derivative liabilities	$ (229)	$ (670)

Segment Information - Additiona

Segment Information - Additional Information (Details) - segment	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting [Abstract]
Number of operating segments	3
Number of reportable segments	3
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer One
Segment Reporting Information [Line Items]
Percentage	23.70%	18.70%
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Two
Segment Reporting Information [Line Items]
Percentage	20.00%	11.60%
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Three
Segment Reporting Information [Line Items]
Percentage	12.20%

Segment Information - Segment O

Segment Information - Segment Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net revenues	$ 212,148	$ 188,200
Sterigenics
Segment Reporting Information [Line Items]
Net revenues	131,151	117,280
Nordion
Segment Reporting Information [Line Items]
Net revenues	25,918	23,625
Nelson Labs
Segment Reporting Information [Line Items]
Net revenues	55,079	47,295
Operating Segments
Segment Reporting Information [Line Items]
Net revenues	212,148	188,200
Segment income	105,317	91,883
Capital expenditures	20,942	12,989
Operating Segments | Sterigenics
Segment Reporting Information [Line Items]
Net revenues	131,151	117,280
Segment income	68,461	61,091
Capital expenditures	19,514	10,940
Operating Segments | Nordion
Segment Reporting Information [Line Items]
Net revenues	25,918	23,625
Segment income	13,786	13,022
Capital expenditures	489	1,234
Operating Segments | Nelson Labs
Segment Reporting Information [Line Items]
Net revenues	55,079	47,295
Segment income	23,070	17,770
Capital expenditures	939	815
Intersegment
Segment Reporting Information [Line Items]
Net revenues	$ (10,500)	$ (10,900)

Segment Information - Reconcili

Segment Information - Reconciliation of Reportable Segment Amounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Share-based compensation expense	$ 3,449	$ 1,725
Loss on extinguishment of debt	14,312	0
Accretion of asset retirement obligations	551	471
Net income (loss) attributable to Sotera Health Company	10,842	(1,964)
Operating Segments
Segment Reporting Information [Line Items]
Segment income	105,317	91,883
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest expense, net	21,282	56,562
Depreciation and amortization	37,661	36,023
Share-based compensation expense	3,449	1,725
(Gain) loss on foreign currency and embedded derivatives	(336)	4,267
Acquisition and divestiture related charges, net	(185)	994
Business optimization project expenses	261	1,049
Plant closure expenses	542	771
Loss on extinguishment of debt	14,312	0
Professional services relating to EO sterilization facilities	13,399	4,146
Accretion of asset retirement obligations	551	490
COVID-19 expenses	299	76
Net income (loss) attributable to Sotera Health Company	$ 14,082	$ (14,220)