Sotera Health (SHC) 10-Q 2 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 25, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
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	262-1410
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		283,070,826
Entity Central Index Key	0001822479
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 261,133	$ 296,407
Restricted cash short-term	1,687	5,247
Accounts receivable, net of allowance for uncollectible accounts of $3,925 and $4,689, respectively	111,069	147,696
Inventories, net	51,342	48,316
Prepaid expenses and other current assets	53,663	53,846
Income taxes receivable	8,285	5,732
Total current assets	487,179	557,244
Property, plant, and equipment, net	979,422	946,914
Operating lease assets	22,517	24,037
Deferred income taxes	4,883	4,993
Post-retirement assets	29,502	28,482
Other assets	42,881	41,242
Other intangible assets, net	390,457	416,318
Goodwill	1,102,851	1,111,190
Total assets	3,059,692	3,130,420
Current liabilities:
Accounts payable	61,576	71,039
Accrued liabilities	61,774	122,471
Deferred revenue	12,882	13,492
Current portion of long-term debt	4,808	4,797
Current portion of finance lease obligations	1,490	8,771
Current portion of operating lease obligations	5,303	5,934
Income taxes payable	4,507	4,150
Total current liabilities	152,340	230,654
Long-term debt, less current portion	2,224,611	2,223,674
Finance lease obligations, less current portion	90,858	63,793
Operating lease obligations, less current portion	19,132	20,087
Noncurrent asset retirement obligations	48,021	47,944
Deferred lease income	18,223	18,762
Post-retirement obligations	8,235	8,439
Noncurrent liabilities	8,728	8,879
Deferred income taxes	60,152	64,454
Total liabilities	2,630,300	2,686,686
See Commitments and contingencies note
Equity:
Common stock, with $0.01 par value, 1,200,000 shares authorized; 286,037 shares issued at March 31, 2024 and December 31, 2023	2,860	2,860
Preferred stock, with $0.01 par value, 120,000 authorized; no shares issued at March 31, 2024 and December 31, 2023	0	0
Treasury stock, at cost (2,966 and 3,207 shares at March 31, 2024 and December 31, 2023, respectively)	(26,042)	(27,182)
Additional paid-in capital	1,220,547	1,215,178
Retained deficit	(648,117)	(654,440)
Accumulated other comprehensive loss	(119,856)	(92,682)
Total equity	429,392	443,734
Total liabilities and equity	$ 3,059,692	$ 3,130,420

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowance for uncollectible accounts	$ 3,925	$ 4,689
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)	286,037,000	286,037,000
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)	2,966,000	3,207,000

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues:
Total net revenues	$ 248,176	$ 220,590
Cost of revenues:
Total cost of revenues	121,061	109,087
Gross profit	127,115	111,503
Operating expenses:
Selling, general and administrative expenses	58,209	61,910
Amortization of intangible assets	15,732	16,227
Total operating expenses	73,941	78,137
Operating income	53,174	33,366
Interest expense, net	41,771	28,870
Foreign exchange (gain) loss	(572)	347
Other expense (income), net	961	(1,253)
Income before income taxes	11,014	5,402
Provision for income taxes	4,691	2,560
Net income	6,323	2,842
Other comprehensive income (loss) net of tax:
Pension and post-retirement benefits (net of taxes of $37 and $(17), respectively)	113	(51)
Interest rate derivatives (net of taxes of $146 and $(3,396), respectively)	419	(9,251)
Foreign currency translation	(27,706)	11,257
Comprehensive (loss) income	$ (20,851)	$ 4,797
Earnings per share:
Basic (in dollars per share)	$ 0.02	$ 0.01
Diluted (in dollars per share)	$ 0.02	$ 0.01
Weighted average number of shares outstanding:
Basic (in shares)	281,913	280,691
Diluted (in shares)	284,062	282,977
Service
Revenues:
Total net revenues	$ 226,481	$ 214,510
Cost of revenues:
Total cost of revenues	110,852	104,210
Product
Revenues:
Total net revenues	21,695	6,080
Cost of revenues:
Total cost of revenues	$ 10,209	$ 4,877

Consolidated Statements of Op_2

Consolidated Statements of Operations and Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Pension and post-retirement benefits, tax	$ 37	$ (17)
Interest rate swaps, tax	$ 146	$ (3,396)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities:
Net income	$ 6,323	$ 2,842
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	20,306	18,931
Amortization of intangible assets	20,124	20,607
Deferred income taxes	(3,441)	(1,770)
Share-based compensation expense	8,663	7,288
Accretion of asset retirement obligations	642	572
Unrealized foreign exchange (gain) loss	(5,061)	802
Unrealized loss on derivatives not designated as hedging instruments	1,833	227
Amortization of debt issuance costs	2,535	1,910
Other	(998)	(1,328)
Changes in operating assets and liabilities:
Accounts receivable	40,569	10,223
Inventories	(4,052)	(9,512)
Other current assets	(250)	(6,318)
Accounts payable	(7,280)	(9,610)
Accrued liabilities	(31,006)	8,826
Georgia EO litigation settlement	(35,000)	0
Income taxes payable / receivable, net	(1,808)	(9,551)
Other liabilities	(176)	(372)
Other long-term assets	(2,224)	104
Net cash provided by operating activities	9,699	33,871
Investing activities:
Purchases of property, plant and equipment	(34,890)	(45,000)
Other investing activities	37	32
Net cash used in investing activities	(34,853)	(44,968)
Financing activities:
Proceeds from long-term borrowings	0	500,000
Payment on long-term borrowings	(1,250)	0
Payment on revolving credit facility	0	(200,000)
Payments of debt issuance costs	(1,291)	(24,457)
Buyout of leased facilities	(6,736)	0
Other financing activities	(2,664)	(1,627)
Net cash (used in) provided by financing activities	(11,941)	273,916
Effect of exchange rate changes on cash and cash equivalents	(1,739)	1,067
Net (decrease) increase in cash and cash equivalents, including restricted cash	(38,834)	263,886
Cash and cash equivalents, including restricted cash, at beginning of period	301,654	396,294
Cash and cash equivalents, including restricted cash, at end of period	262,820	660,180
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	69,735	35,456
Cash paid during the period for income taxes, net of tax refunds received	9,837	14,014
Purchases of property, plant and equipment included in accounts payable	$ 15,454	$ 13,061

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings / (Accumulated Deficit)	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2022		282,421
Beginning balance at Dec. 31, 2022	$ 350,238	$ 2,860	$ (29,775)	$ 1,189,622	$ (705,816)	$ (106,653)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation plans (in shares)		95
Share-based compensation plans	6,090		355	5,735
Comprehensive income (loss):
Pension and post-retirement plan adjustments, net of tax	(51)					(51)
Foreign currency translation	11,257					11,257
Interest rate derivatives, net of tax	(9,251)					(9,251)
Net income	2,842				2,842
Ending balance (in shares) at Mar. 31, 2023		282,516
Ending balance at Mar. 31, 2023	361,125	$ 2,860	(29,420)	1,195,357	(702,974)	(104,698)
Beginning balance (in shares) at Dec. 31, 2023		282,830
Beginning balance at Dec. 31, 2023	443,734	$ 2,860	(27,182)	1,215,178	(654,440)	(92,682)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation plans (in shares)		241
Share-based compensation plans	6,509		1,140	5,369
Comprehensive income (loss):
Pension and post-retirement plan adjustments, net of tax	113					113
Foreign currency translation	(27,706)					(27,706)
Interest rate derivatives, net of tax	419					419
Net income	6,323				6,323
Ending balance (in shares) at Mar. 31, 2024		283,071
Ending balance at Mar. 31, 2024	$ 429,392	$ 2,860	$ (26,042)	$ 1,220,547	$ (648,117)	$ (119,856)

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2024
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 leading global provider of mission-critical end-to-end sterilization solutions, lab testing and advisory services for the healthcare industry 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 16, “Segment Information”. All intercompany balances and transactions have been eliminated in consolidation. 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. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. These unaudited interim financial statements should be read in conjunction with the Company's annual consolidated financial statements and accompanying notes in our 2023 10-K.

Recent Accounting Standards

Recent Accounting Standards	3 Months Ended
	Mar. 31, 2024
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Standards	Recent Accounting Standards Accounting Standards Updates (“ASU”) Issued But Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07-Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in ASU 2023-07 require an entity to provide enhanced disclosures about significant segment expenses. The amendments in this ASU are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is in the process of evaluating the impact of this standard on our consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09-Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this ASU require entities to disclose, on an annual basis, specific categories in the reconciliation of the provision (benefit) for income taxes to the statutory rate and provide additional information for reconciling items that meet a quantitative threshold. Additionally, the update requires entities to disclose a disaggregation of taxes paid by category (federal, state and foreign taxes) as well as individual jurisdictions. For public business entities, the amendments in this ASU are effective for annual periods beginning after December 15, 2024. The Company is in the process of evaluating the impact of this standard on our consolidated financial statements and disclosures.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2024
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, 2024 and 2023: (thousands of U.S. dollars) Three Months Ended March 31, 2024 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 166,497 $ 23,051 $ — $ 189,548 Over time — 956 57,672 58,628 Total $ 166,497 $ 24,007 $ 57,672 $ 248,176 (thousands of U.S. dollars) Three Months Ended March 31, 2023 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 159,997 $ 7,588 $ — $ 167,585 Over time — 963 52,042 53,005 Total $ 159,997 $ 8,551 $ 52,042 $ 220,590 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 $12.9 million and $13.5 million at March 31, 2024 and December 31, 2023, respectively. We recognize deferred revenue after we have transferred control of the goods or services to the customer and all revenue recognition criteria are met.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Raw materials and supplies $ 41,436 $ 43,411 Work-in-process 3,008 471 Finished goods 7,129 4,670 51,573 48,552 Reserve for excess and obsolete inventory (231) (236) Inventories, net $ 51,342 $ 48,316

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2024
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 of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Prepaid taxes $ 3,717 $ 4,129 Prepaid business insurance 6,261 7,174 Prepaid rent 1,193 1,150 Customer contract assets 18,550 17,785 Current deposits 416 715 Prepaid maintenance contracts 448 422 Value added tax receivable 3,549 4,306 Prepaid software licensing 2,265 2,503 Stock supplies 3,754 3,669 Embedded derivative assets 1,667 1,225 Other 11,843 10,768 Prepaid expenses and other current assets $ 53,663 $ 53,846

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2024
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, 2024 were as follows: (thousands of U.S. dollars) Sterigenics Nordion Nelson Labs Total Goodwill at December 31, 2023 $ 659,888 $ 276,929 $ 174,373 $ 1,111,190 Changes due to foreign currency exchange rates (1,682) (5,903) (754) (8,339) Goodwill at March 31, 2024 $ 658,206 $ 271,026 $ 173,619 $ 1,102,851 Other intangible assets consisted of the following: (thousands of U.S. dollars) Gross Carrying Amount Accumulated Amortization As of March 31, 2024 Finite-lived intangible assets Customer relationships $ 654,734 $ 498,395 Proprietary technology 83,975 58,095 Trade names 2,562 1,321 Land-use rights 8,583 1,871 Sealed source and supply agreements 204,435 108,302 Other 4,470 3,096 Total finite-lived intangible assets 958,759 671,080 Indefinite-lived intangible assets Regulatory licenses and other (a) 76,995 — Trade names / trademarks 25,783 — Total indefinite-lived intangible assets 102,778 — Total $ 1,061,537 $ 671,080 As of December 31, 2023 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 657,673 $ 485,188 Proprietary technology 84,918 56,846 Trade names 2,567 1,207 Land-use rights 8,756 1,855 Sealed source and supply agreements 208,919 107,561 Other 4,517 2,905 Total finite-lived intangible assets 967,350 655,562 Indefinite-lived intangible assets Regulatory licenses and other (a) 78,684 — Trade names / trademarks 25,846 — Total indefinite-lived intangible assets 104,530 — Total $ 1,071,880 $ 655,562 (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-year license period as Nordion has demonstrated over its 75 years of history. Amounts include the impact of foreign currency translation. Fully amortized amounts are written off. Amortization expense for finite-lived intangible assets was $20.1 million and $20.6 million for the three months ended March 31, 2024 and 2023, respectively. $15.7 million and $16.2 million was included in “Amortization of intangible assets” in the Consolidated Statements of Operations and Comprehensive Income (Loss) for the three months ended March 31, 2024 and 2023, respectively, whereas the remainder was included in “Cost of revenues.” 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 2024 $ 59,479 2025 42,349 2026 22,197 2027 21,120 2028 20,572 Thereafter 121,962 Total $ 287,679 The weighted-average remaining useful life of the finite-lived intangible assets was approximately 9 years as of March 31, 2024.

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Accrued employee compensation $ 26,450 $ 35,037 Georgia EO litigation settlement reserve — 35,000 Illinois EO litigation settlement reserve — 288 Other legal reserves 460 1,480 Accrued interest expense 2,624 26,681 Embedded derivatives 2,698 414 Professional fees 18,143 12,691 Accrued utilities 2,208 2,056 Insurance accrual 3,336 2,922 Accrued taxes 2,605 2,407 Other 3,250 3,495 Accrued liabilities $ 61,774 $ 122,471

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: (thousands of U.S. dollars) As of March 31, 2024 Gross Amount Unamortized Debt Issuance Costs Unamortized Debt Discount Net Amount Term loan, due 2026 $ 1,763,100 $ (1,472) $ (9,439) $ 1,752,189 Term loan B, due 2026 496,250 (7,197) (11,823) 477,230 2,259,350 (8,669) (21,262) 2,229,419 Less current portion 5,000 (73) (119) 4,808 Long-term debt $ 2,254,350 $ (8,596) $ (21,143) $ 2,224,611 (thousands of U.S. dollars) As of December 31, 2023 Gross Amount Unamortized Debt Issuance Costs Unamortized Debt Discount Net Amount Term loan, due 2026 $ 1,763,100 $ (1,606) $ (10,298) $ 1,751,196 Term loan B, due 2026 497,500 (7,616) (12,609) 477,275 2,260,600 (9,222) (22,907) 2,228,471 Less current portion 5,000 (76) (127) 4,797 Long-term debt $ 2,255,600 $ (9,146) $ (22,780) $ 2,223,674 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 June 13, 2026. The total borrowing capacity under the Revolving Credit Facility is $423.8 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, 2024 and December 31, 2023, total borrowings under the Term Loan were $1,763.1 million. The weighted average interest rate on borrowings under the Term Loan for the three months ended March 31, 2024 and March 31, 2023 was 8.26% and 7.44%, respectively. On March 1, 2024, the Company and SHH entered into Amendment No. 3 (“Amendment No. 3”) to the Revolving Credit Facility. Among other changes, the Amendment provides (i) for new commitments under the existing Revolving Credit Facility to replace existing revolving commitments in an aggregate principal amount of $83.0 million , (ii) that certain of the lenders providing revolving credit commitments shall also provide additional commitments for the issuance of letters of credit under the Revolving Credit Facility in an aggregate principal amount of $37.5 million and (iii) for the extension of the maturity date of the Revolving Credit Facility to the earlier of (a) March 1, 2029, and (b) the date that is 91 days prior to the maturity date of the Company’s existing term loans. Amendment No. 3 does not give effect to any other material changes to the terms and conditions of the Credit Agreement, including with respect to the amount of commitments under the Revolving Credit Facility, which remains $423.8 million , the representations and warranties, events of default, affirmative or negative covenants. On February 23, 2023, we entered into the First Lien Credit Agreement (the “2023 Credit Agreement”), which provides for, among other things, a new Term Loan B facility (the “2023 Term Loan”) in an aggregate principal amount of $500.0 million and bears interest, at the Company’s option, at a variable rate per annum equal to either (x) the Term Secured Overnight Financing Rate (“Term SOFR”) (as defined in the 2023 Credit Agreement) plus an applicable margin of 3.75% or (y) an alternative base rate (“ABR”) plus an applicable margin of 2.75%. The 2023 Credit Agreement is secured on a first priority basis by substantially all of our assets and is guaranteed by certain of our subsidiaries. It is prepayable without premium or penalty at any time six months after the closing date. The principal balance shall be paid at 1% of the aggregate principal amount ($5.0 million) per year, with the balance due at the end of 2026. The Company used the proceeds of the 2023 Term Loan to fund a previously announced $408.0 million EO litigation settlement in Cook County, Illinois and pay down the $200.0 million of existing borrowings under the Revolving Credit Facility concurrent with the funding of the 2023 Term Loan on February 23, 2023. The Company utilized the remaining proceeds to further enhance liquidity and for general corporate purposes. The weighted average interest rate on borrowings under the 2023 Term Loan for the three months ended March 31, 2024 and the three months ended March 31, 2023 was 9.09% and 8.82%, respectively. On March 21, 2023, the Company entered into an Incremental Facility Amendment to the First Lien Credit Agreement (“Revolving Credit Facility Amendment”), which provides for an increase in the commitments under the existing Revolving Credit Facility in an aggregate principal amount of $76.3 million. In addition, certain of the lenders providing revolving credit commitments provided additional commitments for the issuance of the letters of credit under the Revolving Credit Facility in an aggregate principal amount of $165.1 million. The Revolving Credit Facility Amendment also provides for the replacement of the reference interest rate option for Revolving Loans from London Interbank Offered Rate (“LIBOR”) to Secured Overnight Financing Rate (“SOFR”) plus an applicable credit spread adjustment of 0.10% (subject to a minimum floor of 0%). After giving effect to the Revolving Credit Facility Amendment, the aggregate amount of the lenders' revolving commitments is $423.8 million. As of March 31, 2024 there were no borrowings outstanding under the Revolving Credit Facility. The Senior Secured Credit Facilities and 2023 Credit Agreement contain additional covenants that, among other things, restrict, subject to certain exceptions, our ability and the ability of our restricted subsidiaries to engage in certain activities, such as incur indebtedness or permit to exist any lien on any property or asset now owned or hereafter acquired, as specified in the Senior Secured Credit Facilities and 2023 Credit Agreement. The Senior Secured Credit Facilities and 2023 Credit Agreement also contain certain customary affirmative covenants and events of default, including upon a change of control. An event of default under the Senior Secured Credit Facilities and 2023 Credit Agreement would occur if the Company or certain of its subsidiaries received one or more enforceable judgments for payment in an aggregate amount in excess of $100.0 million and the judgments were not stayed or remained undischarged for a period of sixty All of SHH’s obligations under the Senior Secured Credit Facilities and 2023 Credit Agreement 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 2023 Credit Agreement, 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 and 2023 Credit Agreement. 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, 2024, the Company had $23.7 million of letters of credit issued against the Revolving Credit Facility, resulting in total availability under the Revolving Credit Facility of $400.1 million. Term Loan Interest Rate Risk Management The Company utilizes interest rate derivatives to reduce the variability of cash flows in the interest payments associated with our variable rate debt due to changes in SOFR. For additional information on the derivative instruments described above, refer to Note 15, “Financial Instruments and Financial Risk”, “Derivative Instruments.” Aggregate Maturities Aggregate maturities of the Company’s long-term debt, excluding debt discounts, as of March 31, 2024, are as follows: (thousands of U.S. dollars) 2024 3,750 2025 5,000 2026 2,250,600 2027 — 2028 — Thereafter — Total $ 2,259,350

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
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.

Employee Benefits

Employee Benefits	3 Months Ended
	Mar. 31, 2024
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 following defined benefit pension plan disclosure relates to Nordion. Certain immaterial foreign defined benefit pension plans have been excluded from the table below. The interest cost, expected return on plan assets and amortization of net actuarial gain are recorded in “Other expense (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 pens ion benefit f or the defined benefit plans for the three months ended March 31, 2024 and 2023 were as follows: Three Months Ended (thousands of U.S. dollars) March 31, March 31, Service cost $ 145 $ 131 Interest cost 2,651 2,724 Expected return on plan assets (4,019) (4,019) Net periodic benefit $ (1,223) $ (1,164) Other benefit plans Other benefit plans disclosed below relate to Nordion and 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. Certain immaterial other foreign benefit plans have been excluded from the table below. All 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, 2024 and 2023 were as follows: Three Months Ended (thousands of U.S. dollars) March 31, March 31, Service cost $ 3 $ 2 Interest cost 86 90 Amortization of net actuarial gain (33) (44) Net periodic benefit cost $ 56 $ 48 The Company currently has no funding requirements as the Nordion pension plan has a going concern surplus as defined by Canadian federal regulation, which requires solvency testing on defined benefit pension plans on an annual basis.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2024
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 Derivatives Total Beginning balance – January 1, 2024 $ (7,297) $ (91,031) $ 5,646 $ (92,682) Other comprehensive income (loss) before reclassifications 146 (27,706) 4,051 (23,509) Amounts reclassified from accumulated other comprehensive income (loss) (33) (a) — (3,632) (b) (3,665) Net current-period other comprehensive income (loss) 113 (27,706) 419 (27,174) Ending balance – March 31, 2024 $ (7,184) $ (118,737) $ 6,065 $ (119,856) Beginning balance – January 1, 2023 $ 3,209 $ (131,205) $ 21,343 $ (106,653) Other comprehensive income (loss) before reclassifications (7) 11,257 (2,493) 8,757 Amounts reclassified from accumulated other comprehensive income (loss) (44) (a) — (6,758) (b) (6,802) Net current-period other comprehensive income (loss) (51) 11,257 (9,251) 1,955 Ending balance – March 31, 2023 $ 3,158 $ (119,948) $ 12,092 $ (104,698) (a) For defined benefit pension plans, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Other expense (income), net” within the Consolidated Statements of Operations and Comprehensive Income (Loss). (b) For interest rate derivatives, 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, 2024
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 a five-year vesting period (20% per year) beginning on the original vesting commencement date of the corresponding Class B-1 time vesting units, subject to the grantee’s continued services through each vesting date. Upon the occurrence of a change in control of the Company, all then-outstanding unvested shares of our common stock distributed in respect of Class B-1 Units will vest as of the date of consummation of such change in control, subject to the grantee’s continued services through the consummation of the change in control. Restricted stock distributed in respect of pre-IPO Class B-2 Units were considered performance vesting units. The required performance threshold for the vesting of B-2 restricted stock is 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 20%, subject to such grantee’s continued services through such date. Both performance thresholds were satisfied on March 4, 2024 and, as a result, all outstanding B-2 Units fully vested as of that date. 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. We recognized $0.4 million and $0.5 million of share-based compensation expense related to the pre-IPO Class B-1 Units for the three months ended March 31, 2024 and 2023, respectively. A summary of the activity for the three months ended March 31, 2024 related to the restricted stock awards distributed in respect of the pre-IPO awards (Class B-1 and B-2 Units) is presented below: Number of shares Restricted Stock Pre-IPO B-1 Restricted Stock - Pre-IPO B-2 Unvested at December 31, 2023 352,447 987,111 Vested (74,335) (987,111) Unvested at March 31, 2024 278,112 — 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 recog nized $8.2 million ($3.9 million for stock options and $4.3 million for RSUs) and $6.8 million ($3.1 million for stock options and $3.7 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, 2024 and 2023, respectively. Stock Options Stock options generally vest ratably over a period of two Number of Shares Weighted- average Exercise Price Outstanding stock options at December 31, 2023 6,972,661 $ 15.17 Granted 1,570,336 14.59 Forfeited (43,652) 20.77 Outstanding stock options at March 31, 2024 8,499,345 $ 15.04 As of March 31, 2024, there were 3.5 million vested and exercisable stock options. RSUs RSUs generally vest ratably over a period of one Number of Shares Weighted- average Grant Date Fair Value Unvested at December 31, 2023 2,298,836 $ 13.81 Granted 971,342 14.59 Forfeited (20,944) 16.44 Vested (390,805) 18.74 Unvested at March 31, 2024 2,858,429 $ 13.38

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share represents the amount of income attributable to each common share outstanding. Diluted earnings per share represents the amount of income 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. As of March 4, 2024, the performance threshold applicable to all Class B-2 restricted stock awards were fully satisfied, thereby releasing the vesting and forfeiture restrictions on these common shares. Beginning on that date, B-2 restricted stock was not included in the earnings allocation. 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. 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: Net income $ 6,323 $ 2,842 Less: Allocation to participating securities 22 18 Net income attributable to Sotera Health Company common shareholders $ 6,301 $ 2,824 Weighted Average Common Shares: Weighted-average common shares outstanding - basic 281,913 280,691 Dilutive effect of potential common shares 2,149 2,286 Weighted-average common shares outstanding - diluted 284,062 282,977 Earnings per Common Share: Net income attributable to Sotera Health Company common shareholders - basic $ 0.02 $ 0.01 Net income attributable to Sotera Health Company common shareholders - diluted 0.02 0.01 Diluted earnings per share does not consider the following potential common shares as the effect would be anti-dilutive: Three Months Ended in thousands of share amounts March 31, March 31, Stock options 4,720 3,570 RSUs 150 492 Total anti-dilutive securities 4,870 4,062

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
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, as well as gain contingencies, 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 assess these regulatory and legal actions to determine if a contingent liability should be recorded. In making these determinations, we may, depending on the nature of the matter, consult with internal and external legal counsel and technical experts. We establish reserves for specific liabilities in connection with regulatory and legal actions that we determine to be both probable and reasonably estimable. The outcomes of regulatory and legal actions can be difficult to predict and are often resolved over long periods of time, making our probability and estimability determinations highly judgmental. Probability determinations require the analysis of various possible outcomes, assessments of potential damages and the impact of multiple factors beyond our control, including potential actions by others, interpretations of the law, and changes and developments in relevant facts, circumstances, regulations and other laws. If a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability is disclosed, together with an estimate of the range of possible loss if the range is determinable and material. In certain of the matters described below, we are not able to estimate potential liability because of the uncertainties related to the outcome(s) and/or the amount(s) or range(s) of loss. The ultimate resolution of pending regulatory and legal matters in future periods, including the matters described below, may have a material adverse effect on our financial condition, results of operations and/or liquidity. The Company may also incur material defense and settlement costs, diversion of management resources and other adverse effects on our business, financial condition, and/or results of operations. Ethylene Oxide Tort Litigation Sterigenics U.S., LLC (“Sterigenics”) and other medical supply sterilization companies have been subjected to tort lawsuits alleging various injuries caused by low-level environmental exposure to EO used at or emitted from sterilization facilities. Those lawsuits, as detailed further below, are individual claims, as opposed to class actions. Illinois Subsidiaries of the Company and other parties are defendants in approximately 25 lawsuits in Illinois in which plaintiffs allege personal injuries or wrongful death resulting from purported use, emissions and releases of EO from or at Sterigenics’ former Willowbrook facility (the “Willowbrook Cases”). The Willowbrook Cases are pending in the Circuit Court of Cook County and have been assigned to a single judge for coordinated discovery and pretrial proceedings. We intend to vigorously defend the Willowbrook Cases. Georgia Sterigenics, Sotera Health, LLC and other parties are defendants in lawsuits in Georgia in which plaintiffs allege personal injuries, wrongful death and property devaluation resulting from use, emissions and releases of EO from or at Sterigenics’ Atlanta facility (the “Atlanta Cases”). Approximately 255 personal injury and wrongful death claims are pending in the State Court of Cobb County and have been consolidated for pretrial purposes (the “Consolidated Personal Injury Cases”). The Consolidated Personal Injury Cases are proceeding under a case management order pursuant to which a “pool” of eight cases will proceed to judicial determination of general causation issues in Phase 1 and specific causation issues in Phase 2; the first trial of any “pool” case that survives Phases 1 and 2 is not expected to begin before September 2025. The remaining Consolidated Personal Injury Cases (including nine cases that include both personal injury and property claims) are stayed. Two additional personal injury lawsuits pending in Cobb County have not been consolidated. The parties have jointly asked the court to stay one of these cases along with the stayed cases in the Consolidated Personal Injury Cases. In the other case, employees of a sterilization customer of Sterigenics allege they were injured by exposure while working at the customer’s distribution facility to residual EO allegedly emanating from products of the customer that had been sterilized at Sterigenics’ Atlanta facility; discovery is underway and, pursuant to the customer’s contract with Sterigenics, the customer is indemnifying Sterigenics against this lawsuit. Sterigenics and Sotera Health LLC are also defendants in approximately 365 property devaluation lawsuits pending in the State Court of Cobb County that have been consolidated for pretrial purposes (the “Consolidated Property Cases”). Ten of the Consolidated Property Cases are proceeding under case management orders while the remaining cases are stayed. Discovery in five of the cases is underway; dispositive motions remain pending in the other five. We intend to vigorously defend the Atlanta Cases. California In March 2024 and April 2024, two lawsuits were filed against the Company, Sterigenics, other subsidiaries of the Company and other parties in Los Angeles County Superior Court for personal injuries and wrongful death allegedly resulting from emissions and releases of EO from Sterigenics’ Vernon facilities (the “Vernon Cases”). Plaintiffs in these cases allege that 18 cases of cancer and other illnesses were caused by exposure to EO at locations in close proximity to the Vernon facilities, including residences located in Maywood, California, and a commercial facility located next door to Sterigenics’ Vernon facilities. The lawsuits remain in preliminary stages and case management orders have yet to be entered. We intend to vigorously defend the Vernon Cases. New Mexico The Company and certain subsidiaries are defendants in a lawsuit in the Third Judicial District Court, Doña Ana County, New Mexico in which the New Mexico Attorney General ( “NMAG”) alleges that emissions and releases of EO from Sterigenics’ facility in Santa Teresa have deteriorated the air quality in surrounding communities and materially contributed to increased health risks for residents of those communities. In April 2024, the Court of Appeals of the State of New Mexico denied the NMAG’s petition for leave to file an interlocutory appeal of the August 2023 order granting Sterigenics’ motion for summary judgment on strict liability, the Unfair Practices Act claim, and the claims for decreased property values, increased healthcare costs and medical monitoring costs. The case has been remanded to the District Court of Doña Ana County for further proceedings on the remaining claims. A defense motion challenging the Court’s jurisdiction over Sotera Health Company and another defendant also remains pending. The Company, Sterigenics and certain other subsidiaries are also defendants in a lawsuit pending in the United States District Court for the District of New Mexico alleging wrongful death resulting from purported exposure to EO used, emitted and released from Sterigenics’ facility in Santa Teresa, New Mexico while the decedent was working at a different company’s facility approximately one mile away. The case is set for trial in October 2025. We intend to vigorously defend the lawsuits relating to the Santa Teresa facility. * * * Additional EO tort lawsuits may be filed in the future against the Company and/or its subsidiaries relating to Sterigenics’ Willowbrook, Atlanta, Santa Teresa, Vernon or other EO facilities. Based on our view of the strength of the science and related evidence that emissions of EO from Sterigenics’ operations have not caused and could not have caused the harms alleged in such lawsuits, we believe that losses in the remaining or future EO cases are not probable. Although the Company intends to defend itself vigorously on the merits, future settlements of EO tort lawsuits are reasonably possible. The Willowbrook and Atlanta Settlements (as previously defined in Note 20, Commitments and Contingencies of our 2023 10-K) were driven by dynamics unique to the cases that were settled and thus should not give rise to presumptions that the Company will settle additional EO tort lawsuits and/or that any such settlements will be for comparable amounts. Potential trial and settlement outcomes can vary widely based a host of factors. EO tort lawsuits will be presided over by different judges, tried by different counsel presenting different evidence and decided by different juries. The substantive and procedural laws of jurisdictions vary and can meaningfully impact the litigation process and outcome of a case. Each plaintiff’s claim involves unique facts and evidence including the circumstances of the plaintiff’s alleged exposure, the type and severity of the plaintiff’s disease, the plaintiff’s medical history and course of treatment, the location of and other factors related to the plaintiff’s real property, and other circumstances. The outcomes of trials before juries are rarely certain and a judgment rendered or settlement reached in one case is not necessarily representative of potential outcomes of other seemingly comparable cases. As a result, it is not possible to estimate a reasonably possible loss or range of loss with respect to any future EO tort lawsuit, trial or settlement. Insurance Coverage for Environmental Liabilities An environmental liability insurance policy under which we have received coverage for the EO tort lawsuits in Illinois, Georgia and New Mexico described above had limits of $10.0 million per occurrence and $20.0 million in the aggregate. Those per occurrence and aggregate limits were fully utilized in the defense of the Illinois, Georgia and New Mexico litigation. Our insurance for future alleged environmental liabilities excludes coverage for EO claims. We are pursuing additional insurance coverage for our legal expenses related to EO tort lawsuits like the Illinois, Georgia and New Mexico matters described above. In 2021, Sterigenics filed an insurance coverage lawsuit in the U.S. District Court for the Northern District of Illinois relating to two commercial general liability policies issued in the 1980s (the “Northern District of Illinois Coverage Lawsuit”). The court issued an order declaring that the defendant insurer owes Sterigenics and another insured party a duty to defend the Willowbrook Cases (the “Duty to Defend Order”) and entered judgment for Sterigenics in January 2024 in the amount of $110.2 million for certain defense costs incurred in the Willowbrook Cases as of August 2022 (the “Defense Costs Judgment”). The defendant insurer has appealed the Duty to Defend Order and Defense Costs Judgment. Sterigenics is also a party in insurance coverage lawsuits pending in the Circuit Court of Cook County, Illinois and the Delaware Superior Court relating to insurance coverage from various historical commercial general liability policies for certain EO litigation settlement amounts and defense costs that the insurer in the Northern District of Illinois Coverage Lawsuit may fail to fund. The Delaware Superior Court has granted Sterigenics’ motion to stay the case pending resolution of the same and similar issues in the coverage lawsuit pending in the Circuit Court of Cook County, Illinois. It is not possible to predict how much, if any, of the insurance proceeds sought will ultimately be recovered. Sotera Health Company Securities Litigation & Related Matters In January 2023, a stockholder class action was filed in the U.S. District Court for the Northern District of Ohio against the Company, certain past and present directors and senior executives, the Company’s private equity stockholders and the underwriters of the Company’s initial public offering (“IPO”) in November 2020 and the Company’s secondary public offering (“SPO”) in March 2021 (the “Michigan Funds Litigation”). In April 2023, the court appointed the Oakland County Employees’ Retirement System, Oakland County Voluntary Employees’ Beneficiary Association, and Wayne County Employees’ Retirement System (the “Michigan Funds”) to serve as lead plaintiff to prosecute claims on behalf of a proposed class of stockholders who acquired shares of the Company in connection with our IPO or SPO or between November 20, 2020 and September 19, 2022 (the “Proposed Class”). The Michigan Funds allege that statements made regarding the safety of the Company’s use of EO and/or its EO tort lawsuits and other risks of its EO operations violated Sections 11, 12(a)(2) and 15 of the Securities Act of 1933 (when made in the registration statements for the IPO and SPO) and Sections 10(b), Section 20(a) and Rule 10b-5 of the Securities Exchange Act of 1934 (when made in subsequent securities filings and other contexts). Defendants have moved to dismiss the Amended Complaint and that motion remains pending. In May 2023, July 2023 and April 2024, the Company received demands pursuant to 8 Del. C. §220 for inspections of its books and records from shareholders purporting to be investigating the Company’s internal operations, disclosure practices and other matters alleged and at issue in the Michigan Funds Litigation and related to the Company’s March 2024 Secondary Public Offering. The Company is producing documents in response to the 220 Demands. The Company believes that the allegations and claims in the Michigan Funds Litigation and 220 Demands are without merit and plans to vigorously defend the Michigan Funds Litigation .

Financial Instruments and Finan

Financial Instruments and Financial Risk	3 Months Ended
	Mar. 31, 2024
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 From time to time, the Company utilizes interest rate derivatives designated in hedge relationships to manage interest rate risk associated with our variable rate borrowings. These instruments are measured at fair value with changes in fair value recorded as a component of “Accumulated other comprehensive income (loss)” on our Consolidated Balance Sheets. In March 2023, we entered into an interest rate swap agreement with a notional amount of $400.0 million. The interest rate swap was effective on August 23, 2023 and expires on August 23, 2025. We have designated the interest swap as a cash flow hedge designed to hedge the variability of cash flows attributable to changes in the SOFR benchmark interest rate of our 2023 Term Loan (or any successor thereto). We receive interest at the one-month Term SOFR rate and pay a fixed interest rate under the terms of the swap agreement. In May 2022, we entered into two interest rate cap agreements with a combined notional amount of $1,000.0 million for a total option premium of $4.1 million. The interest rate caps became effective as of July 31, 2023 and expire on July 31, 2024. We have designated these interest rate caps as cash flow hedges designed to hedge the variability of cash flows attributable to changes in the benchmark interest rate of our Term Loan (or any successor thereto). Under the current terms of the loan agreement, the benchmark interest rate index transitioned from LIBOR to Term SOFR on June 30, 2023. Accordingly, the interest rate cap agreements hedge the variability of cash flows attributable to changes in SOFR by limiting our cash flow exposure related to Term SOFR under a portion of our variable rate borrowings to 3.5%. In October 2021, we entered into two interest rate cap agreements with a combined notional amount of $1,000.0 million for a total option premium of $1.8 million. Both interest rate caps were effective on December 31, 2022 and expired on July 31, 2023. These interest rate caps were designated as cash flow hedges designed to hedge the variability of cash flows attributable to changes in LIBOR (or its successor), the benchmark interest rate being hedged, by limiting our cash flow exposure related to the LIBOR base rate under a portion of our variable rate borrowings to 1.0%. Derivatives Not Designated in Hedge Relationships Additionally, from time to time, the Company enters into interest rate derivatives to manage economic risks associated with our variable rate borrowings that are not designated in hedge relationships. These instruments are recorded at fair value on the Consolidated Balance Sheets, with any changes in value recorded in “Interest expense, net” in the Consolidated Statements of Operations and Comprehensive Income (Loss). The Company also routinely enters into foreign currency forward contracts to manage foreign currency exchange rate risk of our intercompany loans in certain of our international subsidiaries and non-functional currency assets and liabilities. The foreign currency forward contracts expire on a monthly basis. 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 expense (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, 2024 December 31, 2023 (in U.S. Dollars; notional in millions, fair value in thousands) Fair Value Fair Value Notional Derivative Derivative Notional Derivative Derivative Derivatives designated as hedging instruments Interest rate caps $ 1,000.0 $ 5,828 — $ 1,000.0 $ 8,763 — Interest rate swaps 400.0 3,940 — 400.0 1,487 — Derivatives not designated as hedging instruments Foreign currency forward contracts 198.7 719 — 171.0 149 9 Embedded derivatives 142.7 (a) 1,667 2,698 150.1 1,225 405 Total $ 1,741.4 $ 12,154 $ 2,698 $ 1,721.1 $ 11,624 $ 414 (a) Represents the total notional amounts for certain of the Company’s supply and sales contracts accounted for as embedded derivatives. Embedded derivative assets/liabilities and foreign currency forward contracts are included in “Prepaid expenses and other current assets” and “Accrued Liabilities” on our Consolidated Balance Sheets depending upon their position at period end. Interest rate swaps and interest rate caps are included in “Other assets” and “Noncurrent liabilities”, respectively, on the Consolidated Balance Sheets depending upon their position at period end. The following table summarizes the activities of our derivative instruments for the periods presented, and the line item in which they are recorded in the Consolidated Statements of Operations and Comprehensive Income (Loss): (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Realized gain on interest rate derivatives recorded in interest expense, net (a) (4,897) (9,648) Unrealized loss on embedded derivatives recorded in other expense (income), net 1,833 227 Realized loss on foreign currency forward contracts recorded in foreign exchange (gain) loss 4,008 449 Unrealized gain on foreign currency forward contracts recorded in foreign exchange (gain) loss (580) — (a) For the three months ended March 31, 2024, amounts represent quarterly settlement of interest rate caps and swaps. We expect to reclassify approximately $8.0 million of pre-tax net gains on derivative instruments from accumulated other comprehensive income (loss) to income during the next 12 months associated with our cash flow hedges. Refer to Note 11, “Other Comprehensive Income (Loss)” for unrealized gains on interest rate derivatives, net of applicable tax, recorded in other comprehensive income (loss) and amounts reclassified from accumulated other comprehensive income to interest expense, net of applicable tax, during the three months ended March 31, 2024. 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, 2024 and December 31, 2023, accounts receivable was net of an allowance for uncollectible accounts of $3.9 million and $4.7 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. Our credit team evaluates and regularly monitors changes in the credit risk of our customers. We routinely assess the collectability of accounts receivable and maintain an adequate allowance for uncollectible accounts to address potential credit losses. The process includes a review of customer financial information and credit ratings, current market conditions as well as the expected future economic conditions that may impact the collection of trade receivables. We regularly review our customers’ past due amounts through an analysis of aged accounts receivables, specific customer past due aging amounts, and the history of trade receivables written off. Upon concluding that a receivable balance is not collectible, the balance is written off against the allowance for uncollectible accounts. 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, 2024 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives designated as hedging instruments (a) Interest rate caps $ 5,828 $ — $ 5,828 $ — Interest rate swaps 3,940 — 3,940 — Derivatives not designated as hedging instruments (b) Foreign currency forward contract assets 719 — 719 — Embedded derivative assets 1,667 — 1,667 — Embedded derivative liabilities 2,698 — 2,698 — Current portion of long-term debt (c) Term loan B, due 2026 4,808 — 4,975 — Long-Term Debt (c) Term loan, due 2026 1,752,189 — 1,747,761 — Term loan B, due 2026 472,422 — 488,794 — Finance Lease Obligations (with current portion) (d) 92,348 — 92,348 — As of December 31, 2023 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives designated as hedging instruments (a) Interest rate caps $ 8,763 $ — $ 8,763 $ — Interest rate swaps 1,487 — 1,487 — Derivatives not designated as hedging instruments (b) Foreign currency forward contracts assets 149 — 149 — Foreign currency forward contracts liabilities 9 — 9 — Embedded derivative assets 1,225 — 1,225 — Embedded derivative liabilities 405 — 405 — Current portion of long-term debt (c) Term loan B, due 2026 4,797 — $ 5,000 — Long-Term Debt (c) Term loan, due 2026 1,751,197 — 1,758,163 — Term loan B, due 2026 472,477 — 492,500 — Finance Lease Obligations (with current portion) (d) 72,564 — 72,564 — (a) Derivatives designated as hedging instruments are measured at fair value with changes in fair value recorded as a component of accumulated other comprehensive income (loss). Interest rate caps and swaps are valued using pricing models that incorporate observable market inputs, including interest rate and yield curves. (b) 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). Embedded derivatives are valued using internally developed models that rely on observable market inputs, including foreign currency forward curves. Foreign currency forward contracts are valued by reference to changes in the foreign currency exchange rate over the life of the contract. (c) Carrying amounts of current portion of long-term debt and long-term debt instruments are reported net of discounts and debt issuance costs. The estimated fair values of these instruments are based upon quoted prices for the term loans due in 2026 in inactive markets as provided by an independent fixed income security pricing service. (d) Fair value approximates carrying value.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
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 the Company's annual consolidated financial statements and accompanying notes in our 2023 10-K. Sterigenics Sterigenics provides outsourced terminal sterilization and irradiation services for the medical device, pharmaceutical, food safety and advanced applications markets using three major technologies: gamma irradiation, EO processing and E-beam irradiation. Nordion Nordion is a leading global provider of Co-60 used in the sterilization and irradiation processes for the medical device, pharmaceutical, food safety, and high-performance materials industries, as well as in the treatment of cancer. In addition, Nordion is a leading global provider of gamma irradiation systems. Nelson Labs Nelson Labs provides outsourced microbiological and analytical chemistry testing and advisory services for the medical device and pharmaceutical industries. For the three months ended March 31, 2024, four customers reported within the Nordion segment individually represented 10% or more of the segment’s total net revenues. These customers represented 18.9%, 18.8%, 16.7% and 10.7% of the total segment’s external net revenues for the three months ended March 31, 2024. For the three months ended March 31, 2023, two customers reported within the Nordion segment individually represented 10% or more of the segment's total net revenues. These customers represented 54.6% and 11.3% of the total segment's external net revenues for the three months ended March 31, 2023. The high concentration of revenues from these customers in the three months ended March 31, 2023 mainly stemmed from the low sales volume pattern during that period. (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Segment revenues (a) Sterigenics $ 166,497 $ 159,997 Nordion 24,007 8,551 Nelson Labs 57,672 52,042 Total net revenues $ 248,176 $ 220,590 Segment income (b) Sterigenics $ 85,818 $ 82,840 Nordion 10,785 1,526 Nelson Labs 15,341 14,102 Total segment income $ 111,944 $ 98,468 (a) Revenues are reported net of intersegment sales. Our Nordion segment recognized $10.0 million and $2.9 million in revenues from sales to our Sterigenics segment for the three months ended March 31, 2024 and 2023, respectively, that is not reflected in net revenues in the table above. Intersegment sales for Sterigenics and Nelson Labs are immaterial for both periods presented. (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, investor relations, corporate development, tax, purchasing, and marketing not directly incurred by a segment are allocated to the segments based on total net revenue. Corporate operating expenses that are directly incurred by a segment are reflected in each segment’s income. Capital expenditures by segment for the three months ended March 31, 2024 and 2023 were as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Sterigenics $ 22,274 $ 30,877 Nordion 10,736 10,545 Nelson Labs 1,880 3,578 Total capital expenditures $ 34,890 $ 45,000 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 before taxes is as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Segment income $ 111,944 $ 98,468 Less adjustments: Interest expense, net (a) 41,771 28,870 Depreciation and amortization (b) 40,430 39,538 Share-based compensation (c) 8,657 7,348 Loss on foreign currency and derivatives not designated as hedging instruments, net (d) 1,230 535 Business optimization expenses (e) 54 2,231 Refinancing and secondary offering costs (f) 1,807 — Professional services relating to EO sterilization facilities (g) 6,339 13,972 Accretion of asset retirement obligation (h) 642 572 Consolidated income before taxes $ 11,014 $ 5,402 (a) Interest expense, net presented in this reconciliation for the three months ended March 31, 2023 has been adjusted to conform to the current year presentation to include interest expense, net on Term Loan B attributable to the loan proceeds that were used to fund the $408.0 million Illinois EO litigation settlement. (b) Includes depreciation of Co-60 held at gamma irradiation sites. (c) Represents share-based compensation expense to employees and Non-Employee Directors. (d) Represents the effects of (i) fluctuations in foreign currency exchange rates and (ii) non-cash mark-to-fair value of embedded derivatives relating to certain customer and supply contracts at Nordion. (e) Represents (i) certain costs related to acquisitions and the integration of recent acquisitions, (ii) the earnings impact of fair value adjustments (excluding those recognized within amortization expense) resulting from the businesses acquired, (iii) transition services income and non-cash deferred lease income associated with the terms of the divestiture of the Medical Isotopes business in 2018, (iv) professional fees and other costs associated with business optimization, cost saving and other process enhancement projects, and (v) professional fees, payroll costs, and other costs, including ongoing lease and utility expenses associated with the closure of the Willowbrook, Illinois facility. The three months ended March 31, 2023 includes a $1.0 million cancellation fee received from a tenant in connection with the termination of an office space lease at the Nordion facility. (f) The three months ended March 31, 2024 includes $1.1 million of expenses incurred in connection with the secondary offering of our common stock that closed on March 4, 2024 and write-off of unamortized debt issuance costs in connection with Amendment No. 3 to the Revolving Credit Facility. (g) Represents litigation and other professional fees associated with our EO sterilization facilities. Amounts presented for the three months ended March 31, 2023 have been adjusted to exclude interest expense, net associated with Term Loan B attributable to the loan proceeds that were used to fund the $408.0 million Illinois EO litigation settlement. (h) 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 and are accreted over the life of the asset.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates
Interim Financial Statements	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. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. These unaudited interim financial statements should be read in conjunction with the Company's annual consolidated financial statements and accompanying notes in our 2023 10-K.
Accounting Standards Updates (“ASU”) Issued But Not Yet Adopted	Accounting Standards Updates (“ASU”) Issued But Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07-Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in ASU 2023-07 require an entity to provide enhanced disclosures about significant segment expenses. The amendments in this ASU are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is in the process of evaluating the impact of this standard on our consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09-Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this ASU require entities to disclose, on an annual basis, specific categories in the reconciliation of the provision (benefit) for income taxes to the statutory rate and provide additional information for reconciling items that meet a quantitative threshold. Additionally, the update requires entities to disclose a disaggregation of taxes paid by category (federal, state and foreign taxes) as well as individual jurisdictions. For public business entities, the amendments in this ASU are effective for annual periods beginning after December 15, 2024. The Company is in the process of evaluating the impact of this standard on our consolidated financial statements and disclosures.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and 2023: (thousands of U.S. dollars) Three Months Ended March 31, 2024 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 166,497 $ 23,051 $ — $ 189,548 Over time — 956 57,672 58,628 Total $ 166,497 $ 24,007 $ 57,672 $ 248,176 (thousands of U.S. dollars) Three Months Ended March 31, 2023 Sterigenics Nordion Nelson Labs Consolidated Point in time $ 159,997 $ 7,588 $ — $ 167,585 Over time — 963 52,042 53,005 Total $ 159,997 $ 8,551 $ 52,042 $ 220,590

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Raw materials and supplies $ 41,436 $ 43,411 Work-in-process 3,008 471 Finished goods 7,129 4,670 51,573 48,552 Reserve for excess and obsolete inventory (231) (236) Inventories, net $ 51,342 $ 48,316

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2024
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 of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Prepaid taxes $ 3,717 $ 4,129 Prepaid business insurance 6,261 7,174 Prepaid rent 1,193 1,150 Customer contract assets 18,550 17,785 Current deposits 416 715 Prepaid maintenance contracts 448 422 Value added tax receivable 3,549 4,306 Prepaid software licensing 2,265 2,503 Stock supplies 3,754 3,669 Embedded derivative assets 1,667 1,225 Other 11,843 10,768 Prepaid expenses and other current assets $ 53,663 $ 53,846

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes to goodwill during the three months ended March 31, 2024 were as follows: (thousands of U.S. dollars) Sterigenics Nordion Nelson Labs Total Goodwill at December 31, 2023 $ 659,888 $ 276,929 $ 174,373 $ 1,111,190 Changes due to foreign currency exchange rates (1,682) (5,903) (754) (8,339) Goodwill at March 31, 2024 $ 658,206 $ 271,026 $ 173,619 $ 1,102,851
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, 2024 Finite-lived intangible assets Customer relationships $ 654,734 $ 498,395 Proprietary technology 83,975 58,095 Trade names 2,562 1,321 Land-use rights 8,583 1,871 Sealed source and supply agreements 204,435 108,302 Other 4,470 3,096 Total finite-lived intangible assets 958,759 671,080 Indefinite-lived intangible assets Regulatory licenses and other (a) 76,995 — Trade names / trademarks 25,783 — Total indefinite-lived intangible assets 102,778 — Total $ 1,061,537 $ 671,080 As of December 31, 2023 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 657,673 $ 485,188 Proprietary technology 84,918 56,846 Trade names 2,567 1,207 Land-use rights 8,756 1,855 Sealed source and supply agreements 208,919 107,561 Other 4,517 2,905 Total finite-lived intangible assets 967,350 655,562 Indefinite-lived intangible assets Regulatory licenses and other (a) 78,684 — Trade names / trademarks 25,846 — Total indefinite-lived intangible assets 104,530 — Total $ 1,071,880 $ 655,562 (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-year license period as Nordion has demonstrated over its 75 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, 2024 Finite-lived intangible assets Customer relationships $ 654,734 $ 498,395 Proprietary technology 83,975 58,095 Trade names 2,562 1,321 Land-use rights 8,583 1,871 Sealed source and supply agreements 204,435 108,302 Other 4,470 3,096 Total finite-lived intangible assets 958,759 671,080 Indefinite-lived intangible assets Regulatory licenses and other (a) 76,995 — Trade names / trademarks 25,783 — Total indefinite-lived intangible assets 102,778 — Total $ 1,061,537 $ 671,080 As of December 31, 2023 Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets Customer relationships $ 657,673 $ 485,188 Proprietary technology 84,918 56,846 Trade names 2,567 1,207 Land-use rights 8,756 1,855 Sealed source and supply agreements 208,919 107,561 Other 4,517 2,905 Total finite-lived intangible assets 967,350 655,562 Indefinite-lived intangible assets Regulatory licenses and other (a) 78,684 — Trade names / trademarks 25,846 — Total indefinite-lived intangible assets 104,530 — Total $ 1,071,880 $ 655,562 (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-year license period as Nordion has demonstrated over its 75 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 2024 $ 59,479 2025 42,349 2026 22,197 2027 21,120 2028 20,572 Thereafter 121,962 Total $ 287,679

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: (thousands of U.S. dollars) March 31, 2024 December 31, 2023 Accrued employee compensation $ 26,450 $ 35,037 Georgia EO litigation settlement reserve — 35,000 Illinois EO litigation settlement reserve — 288 Other legal reserves 460 1,480 Accrued interest expense 2,624 26,681 Embedded derivatives 2,698 414 Professional fees 18,143 12,691 Accrued utilities 2,208 2,056 Insurance accrual 3,336 2,922 Accrued taxes 2,605 2,407 Other 3,250 3,495 Accrued liabilities $ 61,774 $ 122,471

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following: (thousands of U.S. dollars) As of March 31, 2024 Gross Amount Unamortized Debt Issuance Costs Unamortized Debt Discount Net Amount Term loan, due 2026 $ 1,763,100 $ (1,472) $ (9,439) $ 1,752,189 Term loan B, due 2026 496,250 (7,197) (11,823) 477,230 2,259,350 (8,669) (21,262) 2,229,419 Less current portion 5,000 (73) (119) 4,808 Long-term debt $ 2,254,350 $ (8,596) $ (21,143) $ 2,224,611 (thousands of U.S. dollars) As of December 31, 2023 Gross Amount Unamortized Debt Issuance Costs Unamortized Debt Discount Net Amount Term loan, due 2026 $ 1,763,100 $ (1,606) $ (10,298) $ 1,751,196 Term loan B, due 2026 497,500 (7,616) (12,609) 477,275 2,260,600 (9,222) (22,907) 2,228,471 Less current portion 5,000 (76) (127) 4,797 Long-term debt $ 2,255,600 $ (9,146) $ (22,780) $ 2,223,674
Schedule of Maturities of Long-term Debt	Aggregate maturities of the Company’s long-term debt, excluding debt discounts, as of March 31, 2024, are as follows: (thousands of U.S. dollars) 2024 3,750 2025 5,000 2026 2,250,600 2027 — 2028 — Thereafter — Total $ 2,259,350

Employee Benefits (Tables)

Employee Benefits (Tables)	3 Months Ended
	Mar. 31, 2024
Postemployment Benefits [Abstract]
Schedule of Net Periodic Benefit Costs	The components of net periodic pens ion benefit f or the defined benefit plans for the three months ended March 31, 2024 and 2023 were as follows: Three Months Ended (thousands of U.S. dollars) March 31, March 31, Service cost $ 145 $ 131 Interest cost 2,651 2,724 Expected return on plan assets (4,019) (4,019) Net periodic benefit $ (1,223) $ (1,164) Three Months Ended (thousands of U.S. dollars) March 31, March 31, Service cost $ 3 $ 2 Interest cost 86 90 Amortization of net actuarial gain (33) (44) Net periodic benefit cost $ 56 $ 48

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2024
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 Derivatives Total Beginning balance – January 1, 2024 $ (7,297) $ (91,031) $ 5,646 $ (92,682) Other comprehensive income (loss) before reclassifications 146 (27,706) 4,051 (23,509) Amounts reclassified from accumulated other comprehensive income (loss) (33) (a) — (3,632) (b) (3,665) Net current-period other comprehensive income (loss) 113 (27,706) 419 (27,174) Ending balance – March 31, 2024 $ (7,184) $ (118,737) $ 6,065 $ (119,856) Beginning balance – January 1, 2023 $ 3,209 $ (131,205) $ 21,343 $ (106,653) Other comprehensive income (loss) before reclassifications (7) 11,257 (2,493) 8,757 Amounts reclassified from accumulated other comprehensive income (loss) (44) (a) — (6,758) (b) (6,802) Net current-period other comprehensive income (loss) (51) 11,257 (9,251) 1,955 Ending balance – March 31, 2023 $ 3,158 $ (119,948) $ 12,092 $ (104,698) (a) For defined benefit pension plans, amounts reclassified from accumulated other comprehensive income (loss) are recorded to “Other expense (income), net” within the Consolidated Statements of Operations and Comprehensive Income (Loss). (b) For interest rate derivatives, 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, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Nonvested Restricted Stock Units Activity	A summary of the activity for the three months ended March 31, 2024 related to the restricted stock awards distributed in respect of the pre-IPO awards (Class B-1 and B-2 Units) is presented below: Number of shares Restricted Stock Pre-IPO B-1 Restricted Stock - Pre-IPO B-2 Unvested at December 31, 2023 352,447 987,111 Vested (74,335) (987,111) Unvested at March 31, 2024 278,112 —
Schedule of Stock Option Activity	The following table summarizes our stock option activity for the three months ended March 31, 2024: Number of Shares Weighted- average Exercise Price Outstanding stock options at December 31, 2023 6,972,661 $ 15.17 Granted 1,570,336 14.59 Forfeited (43,652) 20.77 Outstanding stock options at March 31, 2024 8,499,345 $ 15.04
Schedule of Restricted Stock Activity	The following table summarizes our unvested RSUs activity for the three months ended March 31, 2024: Number of Shares Weighted- average Grant Date Fair Value Unvested at December 31, 2023 2,298,836 $ 13.81 Granted 971,342 14.59 Forfeited (20,944) 16.44 Vested (390,805) 18.74 Unvested at March 31, 2024 2,858,429 $ 13.38

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
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: Net income $ 6,323 $ 2,842 Less: Allocation to participating securities 22 18 Net income attributable to Sotera Health Company common shareholders $ 6,301 $ 2,824 Weighted Average Common Shares: Weighted-average common shares outstanding - basic 281,913 280,691 Dilutive effect of potential common shares 2,149 2,286 Weighted-average common shares outstanding - diluted 284,062 282,977 Earnings per Common Share: Net income attributable to Sotera Health Company common shareholders - basic $ 0.02 $ 0.01 Net income attributable to Sotera Health Company common shareholders - diluted 0.02 0.01
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Diluted earnings per share does not consider the following potential common shares as the effect would be anti-dilutive: Three Months Ended in thousands of share amounts March 31, March 31, Stock options 4,720 3,570 RSUs 150 492 Total anti-dilutive securities 4,870 4,062

Financial Instruments and Fin_2

Financial Instruments and Financial Risk (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 December 31, 2023 (in U.S. Dollars; notional in millions, fair value in thousands) Fair Value Fair Value Notional Derivative Derivative Notional Derivative Derivative Derivatives designated as hedging instruments Interest rate caps $ 1,000.0 $ 5,828 — $ 1,000.0 $ 8,763 — Interest rate swaps 400.0 3,940 — 400.0 1,487 — Derivatives not designated as hedging instruments Foreign currency forward contracts 198.7 719 — 171.0 149 9 Embedded derivatives 142.7 (a) 1,667 2,698 150.1 1,225 405 Total $ 1,741.4 $ 12,154 $ 2,698 $ 1,721.1 $ 11,624 $ 414 (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 table summarizes the activities of our derivative instruments for the periods presented, and the line item in which they are recorded in the Consolidated Statements of Operations and Comprehensive Income (Loss): (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Realized gain on interest rate derivatives recorded in interest expense, net (a) (4,897) (9,648) Unrealized loss on embedded derivatives recorded in other expense (income), net 1,833 227 Realized loss on foreign currency forward contracts recorded in foreign exchange (gain) loss 4,008 449 Unrealized gain on foreign currency forward contracts recorded in foreign exchange (gain) loss (580) — (a) For the three months ended March 31, 2024, amounts represent quarterly settlement of interest rate caps and swaps.
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, 2024 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives designated as hedging instruments (a) Interest rate caps $ 5,828 $ — $ 5,828 $ — Interest rate swaps 3,940 — 3,940 — Derivatives not designated as hedging instruments (b) Foreign currency forward contract assets 719 — 719 — Embedded derivative assets 1,667 — 1,667 — Embedded derivative liabilities 2,698 — 2,698 — Current portion of long-term debt (c) Term loan B, due 2026 4,808 — 4,975 — Long-Term Debt (c) Term loan, due 2026 1,752,189 — 1,747,761 — Term loan B, due 2026 472,422 — 488,794 — Finance Lease Obligations (with current portion) (d) 92,348 — 92,348 — As of December 31, 2023 Fair Value (thousands of U.S. dollars) Carrying Level 1 Level 2 Level 3 Derivatives designated as hedging instruments (a) Interest rate caps $ 8,763 $ — $ 8,763 $ — Interest rate swaps 1,487 — 1,487 — Derivatives not designated as hedging instruments (b) Foreign currency forward contracts assets 149 — 149 — Foreign currency forward contracts liabilities 9 — 9 — Embedded derivative assets 1,225 — 1,225 — Embedded derivative liabilities 405 — 405 — Current portion of long-term debt (c) Term loan B, due 2026 4,797 — $ 5,000 — Long-Term Debt (c) Term loan, due 2026 1,751,197 — 1,758,163 — Term loan B, due 2026 472,477 — 492,500 — Finance Lease Obligations (with current portion) (d) 72,564 — 72,564 — (a) Derivatives designated as hedging instruments are measured at fair value with changes in fair value recorded as a component of accumulated other comprehensive income (loss). Interest rate caps and swaps are valued using pricing models that incorporate observable market inputs, including interest rate and yield curves. (b) 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). Embedded derivatives are valued using internally developed models that rely on observable market inputs, including foreign currency forward curves. Foreign currency forward contracts are valued by reference to changes in the foreign currency exchange rate over the life of the contract. (c) Carrying amounts of current portion of long-term debt and long-term debt instruments are reported net of discounts and debt issuance costs. The estimated fair values of these instruments are based upon quoted prices for the term loans due in 2026 in inactive markets as provided by an independent fixed income security pricing service. (d) Fair value approximates carrying value.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	(thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Segment revenues (a) Sterigenics $ 166,497 $ 159,997 Nordion 24,007 8,551 Nelson Labs 57,672 52,042 Total net revenues $ 248,176 $ 220,590 Segment income (b) Sterigenics $ 85,818 $ 82,840 Nordion 10,785 1,526 Nelson Labs 15,341 14,102 Total segment income $ 111,944 $ 98,468 (a) Revenues are reported net of intersegment sales. Our Nordion segment recognized $10.0 million and $2.9 million in revenues from sales to our Sterigenics segment for the three months ended March 31, 2024 and 2023, respectively, that is not reflected in net revenues in the table above. Intersegment sales for Sterigenics and Nelson Labs are immaterial for both periods presented. (b) Segment income is only provided on a net basis to the chief operating decision-maker and is reported net of intersegment profits. Capital expenditures by segment for the three months ended March 31, 2024 and 2023 were as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Sterigenics $ 22,274 $ 30,877 Nordion 10,736 10,545 Nelson Labs 1,880 3,578 Total capital expenditures $ 34,890 $ 45,000
Schedule of Reconciliation of Operating Profit (Loss) from Segments to Consolidated	A reconciliation of segment income to consolidated income before taxes is as follows: (thousands of U.S. dollars) Three Months Ended March 31, 2024 2023 Segment income $ 111,944 $ 98,468 Less adjustments: Interest expense, net (a) 41,771 28,870 Depreciation and amortization (b) 40,430 39,538 Share-based compensation (c) 8,657 7,348 Loss on foreign currency and derivatives not designated as hedging instruments, net (d) 1,230 535 Business optimization expenses (e) 54 2,231 Refinancing and secondary offering costs (f) 1,807 — Professional services relating to EO sterilization facilities (g) 6,339 13,972 Accretion of asset retirement obligation (h) 642 572 Consolidated income before taxes $ 11,014 $ 5,402 (a) Interest expense, net presented in this reconciliation for the three months ended March 31, 2023 has been adjusted to conform to the current year presentation to include interest expense, net on Term Loan B attributable to the loan proceeds that were used to fund the $408.0 million Illinois EO litigation settlement. (b) Includes depreciation of Co-60 held at gamma irradiation sites. (c) Represents share-based compensation expense to employees and Non-Employee Directors. (d) Represents the effects of (i) fluctuations in foreign currency exchange rates and (ii) non-cash mark-to-fair value of embedded derivatives relating to certain customer and supply contracts at Nordion. (e) Represents (i) certain costs related to acquisitions and the integration of recent acquisitions, (ii) the earnings impact of fair value adjustments (excluding those recognized within amortization expense) resulting from the businesses acquired, (iii) transition services income and non-cash deferred lease income associated with the terms of the divestiture of the Medical Isotopes business in 2018, (iv) professional fees and other costs associated with business optimization, cost saving and other process enhancement projects, and (v) professional fees, payroll costs, and other costs, including ongoing lease and utility expenses associated with the closure of the Willowbrook, Illinois facility. The three months ended March 31, 2023 includes a $1.0 million cancellation fee received from a tenant in connection with the termination of an office space lease at the Nordion facility. (f) The three months ended March 31, 2024 includes $1.1 million of expenses incurred in connection with the secondary offering of our common stock that closed on March 4, 2024 and write-off of unamortized debt issuance costs in connection with Amendment No. 3 to the Revolving Credit Facility. (g) Represents litigation and other professional fees associated with our EO sterilization facilities. Amounts presented for the three months ended March 31, 2023 have been adjusted to exclude interest expense, net associated with Term Loan B attributable to the loan proceeds that were used to fund the $408.0 million Illinois EO litigation settlement. (h) 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 and are accreted over the life of the asset.

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2024 segment
Accounting Policies [Abstract]
Number of operating segments	3
Number of reportable segments	3

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Total net revenues	$ 248,176	$ 220,590
Deferred revenue	12,882		$ 13,492
Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	189,548	167,585
Over time
Disaggregation of Revenue [Line Items]
Total net revenues	58,628	53,005
Sterigenics
Disaggregation of Revenue [Line Items]
Total net revenues	166,497	159,997
Sterigenics | Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	166,497	159,997
Sterigenics | Over time
Disaggregation of Revenue [Line Items]
Total net revenues	0	0
Nordion
Disaggregation of Revenue [Line Items]
Total net revenues	24,007	8,551
Nordion | Point in time
Disaggregation of Revenue [Line Items]
Total net revenues	23,051	7,588
Nordion | Over time
Disaggregation of Revenue [Line Items]
Total net revenues	956	963
Nelson Labs
Disaggregation of Revenue [Line Items]
Total net revenues	57,672	52,042
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	$ 57,672	$ 52,042

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 41,436	$ 43,411
Work-in-process	3,008	471
Finished goods	7,129	4,670
Inventories, gross	51,573	48,552
Reserve for excess and obsolete inventory	(231)	(236)
Inventories, net	$ 51,342	$ 48,316

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid taxes	$ 3,717	$ 4,129
Prepaid business insurance	6,261	7,174
Prepaid rent	1,193	1,150
Customer contract assets	18,550	17,785
Current deposits	416	715
Prepaid maintenance contracts	448	422
Value added tax receivable	3,549	4,306
Prepaid software licensing	2,265	2,503
Stock supplies	3,754	3,669
Embedded derivative assets	1,667	1,225
Other	11,843	10,768
Prepaid expenses and other current assets	$ 53,663	$ 53,846

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 1,111,190
Changes due to foreign currency exchange rates	(8,339)
Ending balance	1,102,851
Sterigenics
Goodwill [Roll Forward]
Beginning balance	659,888
Changes due to foreign currency exchange rates	(1,682)
Ending balance	658,206
Nordion
Goodwill [Roll Forward]
Beginning balance	276,929
Changes due to foreign currency exchange rates	(5,903)
Ending balance	271,026
Nelson Labs
Goodwill [Roll Forward]
Beginning balance	174,373
Changes due to foreign currency exchange rates	(754)
Ending balance	$ 173,619

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 958,759	$ 967,350
Accumulated Amortization	671,080	655,562
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	102,778	104,530
Total	1,061,537	1,071,880
Regulatory licenses and other
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 76,995	78,684
Renewal term	10 years
Trade names / trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 25,783	25,846
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	654,734	657,673
Accumulated Amortization	498,395	485,188
Proprietary technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	83,975	84,918
Accumulated Amortization	58,095	56,846
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,562	2,567
Accumulated Amortization	1,321	1,207
Land-use rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,583	8,756
Accumulated Amortization	1,871	1,855
Sealed source and supply agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	204,435	208,919
Accumulated Amortization	108,302	107,561
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,470	4,517
Accumulated Amortization	$ 3,096	$ 2,905

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 20,124	$ 20,607
Finite-lived intangible assets, remaining amortization period	9 years
Other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 20,100	20,600
Other | Amortization of Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 15,700	$ 16,200

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Schedule of Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
For the remainder of 2024	$ 59,479
2025	42,349
2026	22,197
2027	21,120
2028	20,572
Thereafter	121,962
Total	$ 287,679

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts Payable and Accrued Liabilities [Line Items]
Accrued employee compensation	$ 26,450	$ 35,037
Other legal reserves	460	1,480
Accrued interest expense	2,624	26,681
Embedded derivatives	2,698	414
Professional fees	18,143	12,691
Accrued utilities	2,208	2,056
Insurance accrual	3,336	2,922
Accrued taxes	2,605	2,407
Other	3,250	3,495
Accrued liabilities	61,774	122,471
Ethylene Oxide Tort Litigation – Georgia
Accounts Payable and Accrued Liabilities [Line Items]
Litigation settlement reserve	0	35,000
Ethylene Oxide Tort Litigation - Illinois
Accounts Payable and Accrued Liabilities [Line Items]
Litigation settlement reserve	$ 0	$ 288

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-Term Debt, Gross	$ 2,259,350	$ 2,260,600
Less current portion	5,000	5,000
Long-term debt	2,254,350	2,255,600
Long-term debt	(8,669)	(9,222)
Less current portion	(73)	(76)
Unamortized Debt Issuance Costs	(8,596)	(9,146)
Unamortized discount, excluding current portion	(21,262)	(22,907)
Less current portion	(119)	(127)
Unamortized Debt Discount	(21,143)	(22,780)
Long-Term Debt, Total	2,229,419	2,228,471
Less current portion	4,808	4,797
Long-term debt	2,224,611	2,223,674
Term loan B, due 2026 | Term loan B, due 2026
Debt Instrument [Line Items]
Long-Term Debt, Gross		497,500
Long-term debt		(7,616)
Long-Term Debt, Total		477,275
Secured Debt | Term loan, due 2026
Debt Instrument [Line Items]
Long-Term Debt, Gross	1,763,100	1,763,100
Long-term debt	(1,472)	(1,606)
Unamortized Debt Discount	(9,439)	(10,298)
Long-Term Debt, Total	1,752,189	1,751,196
Secured Debt | Term loan B, due 2026
Debt Instrument [Line Items]
Long-Term Debt, Gross	496,250
Long-term debt	(7,197)
Unamortized Debt Discount	(11,823)	$ (12,609)
Long-Term Debt, Total	$ 477,230

Long-Term Debt - Senior Secured

Long-Term Debt - Senior Secured Credit Facilities (Narrative) (Details) - USD ($)			3 Months Ended
	Feb. 23, 2023	Jan. 09, 2023	Mar. 31, 2024	Mar. 31, 2023	Mar. 01, 2024	Dec. 31, 2023	Mar. 21, 2023	Mar. 01, 2023	Dec. 13, 2019
Debt Instrument [Line Items]
Long-term debt, gross			$ 2,259,350,000			$ 2,260,600,000
Asset Transfer Case | Pending Litigation
Debt Instrument [Line Items]
Amount awarded to other party	$ 408,000,000
Ethylene Oxide Tort Litigation - Illinois | Pending Litigation
Debt Instrument [Line Items]
Amount awarded to other party		$ 408,000,000
Base amount for default			$ 100,000,000
Triggering period for default			60 days
Secured Debt
Debt Instrument [Line Items]
Line of credit facility, prior to expiration period								91 days
Term loan, due 2026 | Secured Debt
Debt Instrument [Line Items]
Long-term debt, gross			$ 1,763,100,000			1,763,100,000
Weighted average interest rate			8.26%	7.44%
Term loan B, due 2026 | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500,000,000
Long-term debt, gross			$ 496,250,000
Weighted average interest rate			9.09%	8.82%
Prepayment period without penalty	6 months
Principal balance payment, percent of amount outstanding	1%
Annual principal payment	$ 5,000,000
Term loan B, due 2026 | Secured Debt | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	3.75%
Term loan B, due 2026 | Secured Debt | Alternative Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
First Lien Notes due 2026 | Secured Debt | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate			0.10%
First Lien Notes due 2026 | Secured Debt | SOFR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			0%
Term loan B, due 2026
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 423,800,000
Debt outstanding					$ 83,000,000
Term loan B, due 2026 | Senior Secured Credit Facilities
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 423,800,000
Extinguishment of debt	$ 200,000,000
Capitalized debt issuance costs			$ 0
Letters of credit outstanding, amount			23,700,000
Unused borrowing capacity			$ 400,100,000
Term loan B, due 2026 | Term loan B, due 2026
Debt Instrument [Line Items]
Long-term debt, gross						$ 497,500,000
Term loan B, due 2026 | First Lien Notes due 2026
Debt Instrument [Line Items]
Maximum borrowing capacity							165,100,000
Term loan B, due 2026 | First Lien Notes due 2026 | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 76,300,000
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 37,500,000

Long-Term Debt - Schedule of Ma

Long-Term Debt - Schedule of Maturities of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
2024	$ 3,750
2025	5,000
2026	2,250,600
2027	0
2028	0
Thereafter	0
Long-Term Debt, Gross	$ 2,259,350	$ 2,260,600

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Effective income tax rate	42.60%	47.40%

Employee Benefits - Schedule of

Employee Benefits - Schedule of Net Periodic Benefit Costs (Details) - Nordion - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 145	$ 131
Interest cost	2,651	2,724
Expected return on plan assets	(4,019)	(4,019)
Net periodic benefit cost	(1,223)	(1,164)
Other Benefits Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	2
Interest cost	86	90
Amortization of net actuarial gain	(33)	(44)
Net periodic benefit cost	$ 56	$ 48

Employee Benefits - Narrative (

Employee Benefits - Narrative (Details) - Nordion - Defined Benefit Pension Plan - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Letters of credit outstanding, amount	$ 16	$ 16
Maximum
Defined Benefit Plan Disclosure [Line Items]
Solvency payment as percent of market value	15%

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 443,734	$ 350,238
Other comprehensive income (loss) before reclassifications	(23,509)	8,757
Amounts reclassified from accumulated other comprehensive income (loss)	(3,665)	(6,802)
Ending balance	429,392	361,125
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(92,682)	(106,653)
Comprehensive (loss) income	(27,174)	1,955
Ending balance	(119,856)	(104,698)
Defined Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(7,297)	3,209
Other comprehensive income (loss) before reclassifications	146	(7)
Amounts reclassified from accumulated other comprehensive income (loss)	(33)	(44)
Comprehensive (loss) income	113	(51)
Ending balance	(7,184)	3,158
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(91,031)	(131,205)
Other comprehensive income (loss) before reclassifications	(27,706)	11,257
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Comprehensive (loss) income	(27,706)	11,257
Ending balance	(118,737)	(119,948)
Interest Rate Derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	5,646	21,343
Other comprehensive income (loss) before reclassifications	4,051	(2,493)
Amounts reclassified from accumulated other comprehensive income (loss)	(3,632)	(6,758)
Comprehensive (loss) income	419	(9,251)
Ending balance	$ 6,065	$ 12,092

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 8.2	$ 6.8
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	$ 0.4	0.5
Restricted Stock | Pre-IPO B-1 | Year One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20%
Restricted Stock | Pre-IPO B-1 | Year Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20%
Restricted Stock | Pre-IPO B-1 | Year Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20%
Restricted Stock | Pre-IPO B-1 | Year Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20%
Restricted Stock | Pre-IPO B-1 | Year Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	20%
Restricted Stock | Pre-IPO B-2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of return on investments	250%
Restricted Stock | Pre-IPO B-2 | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Investment, internal rate of return	20%
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term	10 years
Stock options vested	$ 3.5
Stock options exercisable	$ 3.5
Stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Stock options | 2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 3.9	3.1
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	$ 4.3	$ 3.7

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2024 shares
Pre-IPO B-1
Number of Shares
Beginning balance (in shares)	352,447
Vested (in shares)	(74,335)
Ending balance (in shares)	278,112
Pre-IPO B-2
Number of Shares
Beginning balance (in shares)	987,111
Vested (in shares)	(987,111)
Ending balance (in shares)	0

Share-Based Compensation - Sc_2

Share-Based Compensation - Schedule of Stock Option Activity (Details) - Stock options	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	6,972,661
Granted (in shares) | shares	1,570,336
Forfeited (in shares) | shares	(43,652)
Ending balance (in shares) | shares	8,499,345
Weighted- average Exercise Price
Beginning balance (in shares) | $ / shares	$ 15.17
Granted (in dollars per share) | $ / shares	14.59
Forfeited (in dollars per share) | $ / shares	20.77
Ending balance (in shares) | $ / shares	$ 15.04

Share-Based Compensation - Sc_3

Share-Based Compensation - Schedule of Restricted Stock Activity (Details) - RSUs	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	2,298,836
Granted (in shares) | shares	971,342
Forfeited (in shares) | shares	(20,944)
Vested (in shares) | shares	(390,805)
Ending balance (in shares) | shares	2,858,429
Weighted- average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 13.81
Granted (in dollars per share) | $ / shares	14.59
Forfeited (in dollars per share) | $ / shares	16.44
Vested (in dollars per share) | $ / shares	18.74
Ending balance (in dollars per share) | $ / shares	$ 13.38

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings:
Net income	$ 6,323	$ 2,842
Less: Allocation to participating securities	22	18
Net income attributable to Sotera Health Company common shareholders, Basic	6,301	2,824
Net income attributable to Sotera Health Company common shareholders, Diluted	$ 6,301	$ 2,824
Weighted Average Common Shares:
Weighted-average common shares outstanding - basic (in shares)	281,913,000	280,691,000
Dilutive effect of potential common shares (in shares)	2,149,000	2,286,000
Weighted-average common shares outstanding - diluted (in shares)	284,062,000	282,977,000
Earnings per Common Share:
Net income attributable to Sotera Health Company common shareholders - basic (in dollars per share)	$ 0.02	$ 0.01
Net income attributable to Sotera Health Company common shareholders - diluted (in dollars per share)	$ 0.02	$ 0.01
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4,870,000	4,062,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	4,720,000	3,570,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	150,000	492,000

Commitments and Contingencies (

Commitments and Contingencies (Details)				2 Months Ended	3 Months Ended
	Jan. 09, 2023 segment	Aug. 31, 2022 USD ($)	Aug. 21, 2020 plaintiff	Apr. 30, 2024 claim plaintiff	Mar. 31, 2024 USD ($) case claim
Gain Contingencies [Line Items]
Loss contingency, insurance limits per occurrence | $					$ 10,000,000
Loss contingency, insurance limits | $					$ 20,000,000
Personal Injury And Wrongful Death | California | Subsequent Event
Gain Contingencies [Line Items]
Number of new claims filed | claim				2
Personal Injury | Georgia
Gain Contingencies [Line Items]
Number of new claims filed | claim					2
Number of cases to be stayed (in cases) | claim					1
Pending Litigation
Gain Contingencies [Line Items]
Gross settlement | $		$ 110,200,000
Pending Litigation | Personal Injury And Wrongful Death | Georgia
Gain Contingencies [Line Items]
Number of pending claims | claim					255
Pending Litigation | Personal Injury | Georgia
Gain Contingencies [Line Items]
Number of cases that will proceed to judicial determination (in cases)					8
Number of cases including personal injury and property claims (in cases)					9
Ethylene Oxide Tort Litigation - Illinois | Pending Litigation
Gain Contingencies [Line Items]
Number of plaintiffs | plaintiff			25
Asset Transfer Case | Pending Litigation | Georgia
Gain Contingencies [Line Items]
Number of new claims filed | segment	365
Ethylene Oxide Tort Litigation – Georgia | Property Devaluation | Georgia
Gain Contingencies [Line Items]
Number of new claims filed					10
Ethylene Oxide Tort Litigation – Georgia | Property Devaluation | Georgia | Discovery In Process
Gain Contingencies [Line Items]
Number of new claims filed					5
Ethylene Oxide Tort Litigation – Georgia | Property Devaluation | Georgia | Dispositive Motions Remain Pending
Gain Contingencies [Line Items]
Number of new claims filed					5
Vernon Cases | Personal Injury And Wrongful Death | California | Subsequent Event
Gain Contingencies [Line Items]
Number of plaintiffs | plaintiff				18

Financial Instruments and Fin_3

Financial Instruments and Financial Risk - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	May 31, 2022 USD ($) instrument	Oct. 31, 2021 USD ($) instrument
Derivative [Line Items]
Notional amount	$ 1,741,400,000		$ 1,721,100,000
Interest rate derivatives, net of tax	419,000	$ (9,251,000)
Allowance for uncollectible accounts	3,925,000		4,689,000
Derivatives Designated in Hedge Relationships
Derivative [Line Items]
Interest rate derivatives, net of tax	8,000,000
Derivatives Designated in Hedge Relationships | Interest rate swaps
Derivative [Line Items]
Notional amount	400,000,000	$ 400,000,000	400,000,000
Derivatives Designated in Hedge Relationships | Interest rate caps
Derivative [Line Items]
Notional amount	$ 1,000,000,000		$ 1,000,000,000	$ 1,000,000,000	$ 1,000,000,000
Number of instruments held | instrument				2	2
Option premium					$ 1,800,000
Percent of borrowing limitation due to cash flow exposure				3.50%	1%
Derivatives Designated in Hedge Relationships | Interest Rate Cap October 2017
Derivative [Line Items]
Option premium				$ 4,100,000

Financial Instruments and Fin_4

Financial Instruments and Financial Risk - Schedule of Derivative Instruments (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	May 31, 2022	Oct. 31, 2021
Derivative [Line Items]
Notional Amount	$ 1,741,400,000	$ 1,721,100,000
Fair value, derivative assets	12,154,000	11,624,000
Fair value, derivative liabilities	2,698,000	414,000
Derivatives designated as hedging instruments | Interest rate caps
Derivative [Line Items]
Notional Amount	1,000,000,000	1,000,000,000		$ 1,000,000,000	$ 1,000,000,000
Fair value, derivative assets	5,828,000	8,763,000
Fair value, derivative liabilities	0	0
Derivatives designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Notional Amount	400,000,000	400,000,000	$ 400,000,000
Fair value, derivative assets	3,940,000	1,487,000
Fair value, derivative liabilities	0	0
Derivatives not designated as hedging instruments | Foreign currency forward contracts
Derivative [Line Items]
Notional Amount	198,700,000	171,000,000
Fair value, derivative assets	719,000	149,000
Fair value, derivative liabilities	0	9,000
Derivatives not designated as hedging instruments | Embedded derivatives
Derivative [Line Items]
Notional Amount	142,700,000	150,100,000
Fair value, derivative assets	1,667,000	1,225,000
Fair value, derivative liabilities	$ 2,698,000	$ 405,000

Financial Instruments and Fin_5

Financial Instruments and Financial Risk - Schedule of Derivative Instruments, Gain (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on derivatives not designated as hedging instruments	$ 1,833	$ 227
Interest rate caps
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain on interest rate derivatives recorded in interest expense, net	(4,897)	(9,648)
Embedded Derivative
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized loss on derivatives not designated as hedging instruments	1,833	227
Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized loss on foreign currency forward contracts recorded in foreign exchange (gain) loss	4,008	449
Unrealized gain on foreign currency forward contracts recorded in foreign exchange (gain) loss	$ (580)	$ 0

Financial Instruments and Fin_6

Financial Instruments and Financial Risk - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative asset	$ 12,154	$ 11,624
Derivative liabilities	2,698	414
Derivatives Designated as Hedging Instrument | Interest rate caps
Derivative [Line Items]
Derivative asset	5,828	8,763
Derivative liabilities	0	0
Derivatives Designated as Hedging Instrument | Interest rate caps | Level 1
Derivative [Line Items]
Derivative asset	0	0
Derivatives Designated as Hedging Instrument | Interest rate caps | Level 2
Derivative [Line Items]
Derivative asset	5,828	8,763
Derivatives Designated as Hedging Instrument | Interest rate caps | Level 3
Derivative [Line Items]
Derivative asset	0	0
Derivatives Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Derivative asset	3,940	1,487
Derivative liabilities	0	0
Derivatives Designated as Hedging Instrument | Interest rate swaps | Level 1
Derivative [Line Items]
Derivative asset	0	0
Derivatives Designated as Hedging Instrument | Interest rate swaps | Level 2
Derivative [Line Items]
Derivative asset	3,940	1,487
Derivatives Designated as Hedging Instrument | Interest rate swaps | Level 3
Derivative [Line Items]
Derivative asset	0	0
Derivatives Designated as Hedging Instrument | Carrying Amount | Interest rate caps
Derivative [Line Items]
Derivative asset	5,828	8,763
Derivatives Designated as Hedging Instrument | Carrying Amount | Interest rate swaps
Derivative [Line Items]
Derivative asset	3,940	1,487
Derivatives Not Designated as Hedging Instruments | Term loan B, due 2026 | Level 1
Derivative [Line Items]
Current portion of long-term debt	0	0
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Term loan B, due 2026 | Level 2
Derivative [Line Items]
Current portion of long-term debt	4,975	5,000
Long-term debt	488,794	492,500
Derivatives Not Designated as Hedging Instruments | Term loan B, due 2026 | Level 3
Derivative [Line Items]
Current portion of long-term debt	0	0
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Term loan, due 2026 | Level 1
Derivative [Line Items]
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Term loan, due 2026 | Level 2
Derivative [Line Items]
Long-term debt	1,747,761	1,758,163
Derivatives Not Designated as Hedging Instruments | Term loan, due 2026 | Level 3
Derivative [Line Items]
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Finance Lease Obligations (with current portion) | Level 1
Derivative [Line Items]
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Finance Lease Obligations (with current portion) | Level 2
Derivative [Line Items]
Long-term debt	92,348	72,564
Derivatives Not Designated as Hedging Instruments | Finance Lease Obligations (with current portion) | Level 3
Derivative [Line Items]
Long-term debt	0	0
Derivatives Not Designated as Hedging Instruments | Foreign Exchange Forward Assets and Liabilities | Level 1
Derivative [Line Items]
Derivative asset	0	0
Derivative liabilities		0
Derivatives Not Designated as Hedging Instruments | Foreign Exchange Forward Assets and Liabilities | Level 2
Derivative [Line Items]
Derivative asset	719	149
Derivative liabilities		9
Derivatives Not Designated as Hedging Instruments | Foreign Exchange Forward Assets and Liabilities | Level 3
Derivative [Line Items]
Derivative asset	0	0
Derivative liabilities		0
Derivatives Not Designated as Hedging Instruments | Embedded Derivative Assets and Liabilities
Derivative [Line Items]
Derivative asset	1,667	1,225
Derivative liabilities	2,698	405
Derivatives Not Designated as Hedging Instruments | Embedded Derivative Assets and Liabilities | Level 1
Derivative [Line Items]
Derivative asset	0	0
Derivative liabilities	0	0
Derivatives Not Designated as Hedging Instruments | Embedded Derivative Assets and Liabilities | Level 2
Derivative [Line Items]
Derivative asset	1,667	1,225
Derivative liabilities	2,698	405
Derivatives Not Designated as Hedging Instruments | Embedded Derivative Assets and Liabilities | Level 3
Derivative [Line Items]
Derivative asset	0	0
Derivative liabilities	0	0
Derivatives Not Designated as Hedging Instruments | Carrying Amount | Term loan B, due 2026
Derivative [Line Items]
Current portion of long-term debt	4,808	4,797
Long-term debt	472,422	472,477
Derivatives Not Designated as Hedging Instruments | Carrying Amount | Term loan, due 2026
Derivative [Line Items]
Long-term debt	1,752,189	1,751,197
Derivatives Not Designated as Hedging Instruments | Carrying Amount | Finance Lease Obligations (with current portion)
Derivative [Line Items]
Long-term debt	92,348	72,564
Derivatives Not Designated as Hedging Instruments | Carrying Amount | Foreign Exchange Forward Assets and Liabilities
Derivative [Line Items]
Derivative asset	719	149
Derivative liabilities		9
Derivatives Not Designated as Hedging Instruments | Carrying Amount | Embedded Derivative Assets and Liabilities
Derivative [Line Items]
Derivative asset	1,667	1,225
Derivative liabilities	$ 2,698	$ 405

Segment Information - Narrative

Segment Information - Narrative (Details) - segment	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting [Abstract]
Number of reportable segments	3
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Customer One
Segment Reporting Information [Line Items]
Percentage	18.90%	54.60%
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Customer Two
Segment Reporting Information [Line Items]
Percentage	18.80%	11.30%
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Customer Three
Segment Reporting Information [Line Items]
Percentage	16.70%
Operating Segments | Nordion | Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Customer Four
Segment Reporting Information [Line Items]
Percentage	10.70%

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Total net revenues	$ 248,176	$ 220,590
Sterigenics
Segment Reporting Information [Line Items]
Total net revenues	166,497	159,997
Nordion
Segment Reporting Information [Line Items]
Total net revenues	24,007	8,551
Nelson Labs
Segment Reporting Information [Line Items]
Total net revenues	57,672	52,042
Operating Segments
Segment Reporting Information [Line Items]
Total net revenues	248,176	220,590
Total segment income	111,944	98,468
Total capital expenditures	34,890	45,000
Operating Segments | Sterigenics
Segment Reporting Information [Line Items]
Total net revenues	166,497	159,997
Total segment income	85,818	82,840
Total capital expenditures	22,274	30,877
Operating Segments | Nordion
Segment Reporting Information [Line Items]
Total net revenues	24,007	8,551
Total segment income	10,785	1,526
Total capital expenditures	10,736	10,545
Operating Segments | Nelson Labs
Segment Reporting Information [Line Items]
Total net revenues	57,672	52,042
Total segment income	15,341	14,102
Total capital expenditures	1,880	3,578
Intersegment
Segment Reporting Information [Line Items]
Total net revenues	$ 10,000	$ 2,900

Segment Information - Schedul_2

Segment Information - Schedule of Reconciliation of Operating Profit (Loss) from Segments to Consolidated (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 09, 2023	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Share-based compensation		$ 8,663	$ 7,288
Accretion of asset retirement obligations		642	572
Secondary offering expense- instant debt		1,100
Cancellation fee received from a tenant in connection with the termination			1,000
Ethylene Oxide Tort Litigation - Illinois | Pending Litigation
Segment Reporting Information [Line Items]
Amount awarded to other party	$ 408,000
Operating Segments
Segment Reporting Information [Line Items]
Total segment income		111,944	98,468
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest expense, net		41,771	28,870
Depreciation and amortization		40,430	39,538
Share-based compensation		8,657	7,348
Loss on foreign currency and derivatives not designated as hedging instruments, net		1,230	535
Business optimization expenses		54	2,231
Refinancing and secondary offering costs		1,807	0
Professional services and other expenses relating to EO sterilization facilities		6,339	13,972
Accretion of asset retirement obligations		642	572
Consolidated income before taxes		$ 11,014	$ 5,402