Iron Mountain (IRM) 10-Q 2 May 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	Apr. 26, 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	1-13045
Entity Registrant Name	IRON MOUNTAIN INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-2588479
Entity Address, Address Line One	85 New Hampshire Avenue
Entity Address, Address Line Two	Suite 150
Entity Address, City or Town	Portsmouth
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03801
City Area Code	617
Local Phone Number	535-4766
Title of 12(b) Security	Common Stock, $.01 par value
Trading Symbol	IRM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Emerging Growth Company	false
Small Business Entity	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		293,133,321
Entity Central Index Key	0001020569
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 191,655	$ 222,789
Accounts receivable (less allowances of $77,413 and $74,762 as of March 31, 2024 and December 31, 2023, respectively)	1,268,061	1,259,826
Prepaid expenses and other	275,358	252,930
Total Current Assets	1,735,074	1,735,545
Property, Plant and Equipment:
Property, plant and equipment	10,647,036	10,373,989
Less—Accumulated depreciation	(4,108,897)	(4,059,120)
Property, Plant and Equipment, Net	6,538,139	6,314,869
Other Assets, Net:
Goodwill	5,107,473	5,017,912
Customer and supplier relationships and other intangible assets	1,330,638	1,279,800
Operating lease right-of-use assets	2,677,803	2,696,024
Other	440,429	429,652
Total Other Assets, Net	9,556,343	9,423,388
Total Assets	17,829,556	17,473,802
Current Liabilities:
Current portion of long-term debt	118,771	120,670
Accounts payable	524,901	539,594
Accrued expenses and other current liabilities (includes current portion of operating lease liabilities)	1,052,454	1,250,259
Deferred revenue	332,801	325,665
Total Current Liabilities	2,028,927	2,236,188
Long-term Debt, net of current portion	12,588,569	11,812,500
Long-term Operating Lease Liabilities, net of current portion	2,525,552	2,562,394
Other Long-term Liabilities	255,491	237,590
Deferred Income Taxes	233,135	235,410
Commitments and Contingencies
Redeemable Noncontrolling Interests	179,222	177,947
Iron Mountain Incorporated Stockholders' Equity:
Preferred stock (par value $0.01; authorized 10,000,000 shares; none issued and outstanding)	0	0
Common stock (par value $0.01; authorized 400,000,000 shares; issued and outstanding 293,085,683 and 292,142,739 shares as of March 31, 2024 and December 31, 2023, respectively)	2,931	2,921
Additional paid-in capital	4,518,644	4,533,691
(Distributions in excess of earnings) Earnings in excess of distributions	(4,074,243)	(3,953,808)
Accumulated other comprehensive items, net	(428,797)	(371,156)
Total Iron Mountain Incorporated Stockholders' Equity	18,535	211,648
Noncontrolling Interests	125	125
Total Equity	18,660	211,773
Total Liabilities and Equity	$ 17,829,556	$ 17,473,802

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 77,413	$ 74,762
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares (in shares)	10,000,000	10,000,000
Preferred stock, issued shares (in shares)	0	0
Preferred stock, outstanding shares (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	400,000,000	400,000,000
Common stock, issued shares (in shares)	293,085,683	292,142,739
Common stock, outstanding shares (in shares)	293,085,683	292,142,739

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues:
Total Revenues	$ 1,476,863	$ 1,314,349
Operating Expenses:
Cost of sales (excluding depreciation and amortization)	653,255	571,626
Selling, general and administrative	319,465	294,520
Depreciation and amortization	209,555	182,094
Acquisition and Integration Costs	7,809	1,595
Restructuring and other transformation	40,767	36,913
Loss (gain) on disposal/write-down of property, plant and equipment, net	389	(13,061)
Total Operating Expenses	1,231,240	1,073,687
Operating Income (Loss)	245,623	240,662
Interest Expense, Net (includes Interest Income of $3,660 and $2,907 for the three months ended March 31, 2024 and 2023, respectively)	164,519	137,169
Other (Income) Expense, Net	(12,530)	21,200
Net Income (Loss) Before Provision (Benefit) for Income Taxes	93,634	82,293
Provision (Benefit) for Income Taxes	16,609	16,758
Net Income (Loss)	77,025	65,535
Less: Net Income (Loss) Attributable to Noncontrolling Interests	2,964	940
Net Income (Loss) Attributable to Iron Mountain Incorporated	$ 74,061	$ 64,595
Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated:
Basic (in dollars per share)	$ 0.25	$ 0.22
Diluted (in dollars per share)	$ 0.25	$ 0.22
Weighted average common shares outstanding-basic (in shares)	292,746,000	291,442,000
Weighted average common shares outstanding-diluted (in shares)	295,221,000	293,049,000
Storage rental
Revenues:
Total Revenues	$ 884,842	$ 810,089
Service
Revenues:
Total Revenues	$ 592,021	$ 504,260

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Interest income	$ 3,660	$ 2,907

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 77,025	$ 65,535
Other Comprehensive (Loss) Income:
Foreign Currency Translation Adjustment	(67,269)	40,226
Change in Fair Value of Derivative Instruments	11,388	(3,442)
Reclassifications from Accumulated Other Comprehensive Items, net	(2,528)	0
Total Other Comprehensive (Loss) Income:	(58,409)	36,784
Comprehensive Income (Loss)	18,616	102,319
Comprehensive Income (Loss) Attributable to Noncontrolling Interests	2,196	1,489
Comprehensive Income (Loss) Attributable to Iron Mountain Incorporated	$ 16,420	$ 100,830

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	(DISTRIBUTIONS IN EXCESS OF EARNINGS) EARNINGS IN EXCESS OF DISTRIBUTIONS	ACCUMULATED OTHER COMPREHENSIVE ITEMS, NET	NONCONTROLLING INTERESTS	REDEEMABLE NONCONTROLLING INTERESTS
Beginning of Period at Dec. 31, 2022	$ 636,793	$ 2,908	$ 4,468,035	$ (3,392,272)	$ (442,003)	$ 125
Beginning balance (in shares) at Dec. 31, 2022		290,830,296
Increase (Decrease) in Stockholders' Equity
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation	(8,762)	$ 8	(8,770)
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation (in shares)		754,703
Parent cash dividends declared	(183,272)			(183,272)
Other comprehensive (loss) income	36,235				36,235
Net income (loss)	64,595			64,595
End of Period at Mar. 31, 2023	545,589	$ 2,916	4,459,265	(3,510,949)	(405,768)	125
Ending balance (in shares) at Mar. 31, 2023		291,584,999
Beginning of redeemable noncontrolling interest at Dec. 31, 2022							$ 95,160
Increase (Decrease) in Temporary Equity [Roll Forward]
Other comprehensive (loss) income							549
Net income (loss)							940
Noncontrolling interests dividends							(1,019)
Ending of redeemable noncontrolling interest at Mar. 31, 2023							95,630
Beginning of Period at Dec. 31, 2023	$ 211,773	$ 2,921	4,533,691	(3,953,808)	(371,156)	125
Beginning balance (in shares) at Dec. 31, 2023	292,142,739	292,142,739
Increase (Decrease) in Stockholders' Equity
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation	$ (15,459)	$ 10	(15,469)
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation (in shares)		942,944
Changes in equity related to redeemable noncontrolling interests	422		422
Parent cash dividends declared	(194,496)			(194,496)
Other comprehensive (loss) income	(57,641)				(57,641)
Net income (loss)	74,061			74,061
End of Period at Mar. 31, 2024	$ 18,660	$ 2,931	4,518,644	$ (4,074,243)	$ (428,797)	$ 125
Ending balance (in shares) at Mar. 31, 2024	293,085,683	293,085,683
Beginning of redeemable noncontrolling interest at Dec. 31, 2023	$ 177,947						177,947
Increase (Decrease) in Temporary Equity [Roll Forward]
Changes in equity related to redeemable noncontrolling interests	422		$ 422
Other comprehensive (loss) income							(768)
Net income (loss)							2,964
Noncontrolling interests dividends							(499)
Ending of redeemable noncontrolling interest at Mar. 31, 2024	$ 179,222						$ 179,222

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash Flows from Operating Activities:
Net income (loss)	$ 77,025	$ 65,535
Adjustments to reconcile net income (loss) to cash flows from operating activities:
Depreciation	143,633	120,066
Amortization (includes amortization of deferred financing costs and discounts of $6,100 and $4,332 for the three months ended March 31, 2024 and 2023, respectively)	72,022	66,360
Revenue reduction associated with amortization of customer inducements and above- and below-market leases	1,321	1,760
Stock-based compensation expense	14,039	12,509
Provision (benefit) for deferred income taxes	1,125	4,183
Loss (gain) on disposal/write-down of property, plant and equipment, net	389	(13,061)
Foreign currency transactions and other, net	(5,091)	34,435
(Increase) decrease in assets	(29,738)	(33,530)
(Decrease) increase in liabilities	(144,687)	(129,449)
Cash Flows from Operating Activities	130,038	128,808
Cash Flows from Investing Activities:
Capital expenditures	(381,145)	(265,906)
Cash paid for acquisitions, net of cash acquired	(122,479)	(1,094)
Customer inducements	(2,286)	(1,357)
Contract costs	(25,304)	(24,014)
Investments in joint ventures and other investments	0	(15,830)
Proceeds from sales of property and equipment and other, net	5,605	35,658
Cash Flows from Investing Activities	(525,609)	(272,543)
Cash Flows from Financing Activities:
Repayment of revolving credit facility, term loan facilities and other debt	(1,730,252)	(4,649,926)
Proceeds from revolving credit facility, term loan facilities and other debt	2,479,378	5,008,631
Equity distribution to noncontrolling interests	(499)	(1,019)
Parent cash dividends	(198,013)	(186,514)
Payment of deferred purchase obligation	(158,677)	0
Net (payments) proceeds associated with employee stock-based awards	(29,498)	(21,271)
Other, net	(340)	0
Cash Flows from Financing Activities	362,099	149,901
Effect of Exchange Rates on Cash and Cash Equivalents	2,338	(1,521)
(Decrease) increase in Cash and Cash Equivalents	(31,134)	4,645
Cash and Cash Equivalents, Beginning of Period	222,789	141,797
Cash and Cash Equivalents, End of Period	191,655	146,442
Supplemental Information:
Cash Paid for Interest	274,796	204,902
Cash Paid for Income Taxes, Net	18,613	18,629
Non-Cash Investing and Financing Activities:
Financing Leases and Other	38,082	20,194
Accrued Capital Expenditures	210,255	207,425
Deferred Purchase Obligations and Other Deferred Payments	133,713	197,222
Dividends Payable	$ 198,875	$ 191,030

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Cash Flows [Abstract]
Deferred financing costs and discount included in amortization	$ 6,100	$ 4,332

General

General	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	GENERAL The unaudited condensed consolidated financial statements of Iron Mountain Incorporated, a Delaware corporation, and its subsidiaries ("we" or "us"), have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). Certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been omitted pursuant to those rules and regulations, but we believe that the disclosures included herein are adequate to make the information presented not misleading. The interim condensed consolidated financial statements are presented herein and, in the opinion of management, reflect all adjustments of a normal recurring nature necessary for a fair presentation. Interim results are not necessarily indicative of results for a full year. The Condensed Consolidated Financial Statements and Notes thereto, which are included herein, should be read in conjunction with the Consolidated Financial Statements and Notes thereto for the year ended December 31, 2023 included in our Annual Report on Form 10-K filed with the SEC on February 22, 2024 (our "Annual Report"). In September 2022, we announced a global program designed to accelerate the growth of our business ("Project Matterhorn"). See Note 11.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A. CASH AND CASH EQUIVALENTS Cash and cash equivalents include cash on hand and cash invested in highly liquid short-term securities, which have remaining maturities at the date of purchase of less than 90 days. Cash and cash equivalents are carried at cost, which approximates fair value. B. ACCOUNTS RECEIVABLE We maintain an allowance for doubtful accounts and a credit memo reserve for estimated losses resulting from the potential inability of our customers to make required payments and potential disputes regarding billing and service issues. The rollforward of the allowance for doubtful accounts and credit memo reserves for the three months ended March 31, 2024 is as follows: Balance as of December 31, 2023 $ 74,762 Credit memos charged to revenue 24,035 Allowance for bad debts charged to expense 14,338 Deductions and other (1) (35,722) Balance as of March 31, 2024 $ 77,413 (1) Primarily consists of the issuance of credit memos, the write-off of accounts receivable and the impact associated with currency translation adjustments. C. LEASES We lease facilities for certain warehouses, data centers and office space. We also have land leases, including those on which certain facilities are located. Operating and financing lease right-of-use assets and lease liabilities as of March 31, 2024 and December 31, 2023 are as follows: DESCRIPTION MARCH 31, 2024 DECEMBER 31, 2023 Assets: Operating lease right-of-use assets $ 2,677,803 $ 2,696,024 Financing lease right-of-use assets, net of accumulated depreciation (1) 318,753 304,600 Liabilities: Current Operating lease liabilities $ 301,344 $ 291,795 Financing lease liabilities (1) 39,973 39,089 Long-term Operating lease liabilities $ 2,525,552 $ 2,562,394 Financing lease liabilities (1) 323,653 310,776 (1) Financing lease right-of-use assets, current financing lease liabilities and long-term financing lease liabilities are included within Property, plant and equipment, net, Current portion of long-term debt and Long-term debt, net of current portion, respectively, within our Condensed Consolidated Balance Sheets. The components of the lease expense for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, DESCRIPTION 2024 2023 Operating lease cost (1) $ 171,746 $ 155,873 Financing lease cost: Depreciation of financing lease right-of-use assets $ 10,944 $ 10,008 Interest expense for financing lease liabilities 5,221 4,341 (1) Operating lease cost, the majority of which is included in Cost of sales, includes variable lease costs of $38,094 and $31,580 for the three months ended March 31, 2024 and 2023, respectively. Other information: Supplemental cash flow information relating to our leases for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, CASH PAID FOR AMOUNTS INCLUDED IN MEASUREMENT OF LEASE LIABILITIES: 2024 2023 Operating cash flows used in operating leases $ 117,336 $ 108,723 Operating cash flows used in financing leases (interest) 5,221 4,341 Financing cash flows used in financing leases 10,679 11,714 NON-CASH ITEMS: Operating lease modifications and reassessments $ (262) $ 18,163 New operating leases (including acquisitions and sale-leaseback transactions) 64,556 113,853 D. GOODWILL Our reporting units as of December 31, 2023 are described in detail in Note 2.l. to Notes to Consolidated Financial Statements included in our Annual Report. The changes in the carrying value of goodwill attributable to each reportable segment and Corporate and Other (as defined in Note 9) for the three months ended March 31, 2024 are as follows: GLOBAL RIM BUSINESS GLOBAL DATA CENTER BUSINESS CORPORATE AND OTHER TOTAL CONSOLIDATED Goodwill balance, net of accumulated amortization, as of December 31, 2023 $ 3,911,945 $ 478,930 $ 627,037 $ 5,017,912 Tax deductible goodwill acquired during the period — — 131,695 131,695 Fair value and other adjustments 143 (186) — (43) Currency effects (38,502) (2,995) (594) (42,091) Goodwill balance, net of accumulated amortization, as of March 31, 2024 $ 3,873,586 $ 475,749 $ 758,138 $ 5,107,473 Accumulated goodwill impairment balance as of March 31, 2024 $ 132,409 $ — $ 26,011 $ 158,420 E. FAIR VALUE MEASUREMENTS The assets and liabilities carried at fair value measured on a recurring basis as of March 31, 2024 and December 31, 2023 are as follows: FAIR VALUE MEASUREMENTS AT MARCH 31, 2024 USING DESCRIPTION TOTAL CARRYING VALUE AT MARCH 31, 2024 QUOTED PRICES IN SIGNIFICANT OTHER SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) (2) Money Market Funds $ 6,027 $ — $ 6,027 $ — Time Deposits 32,014 — 32,014 — Trading Securities 10,662 6,783 3,879 — Derivative Assets 20,290 — 20,290 — Deferred Purchase Obligations (1) 113,471 — — 113,471 FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2023 USING DESCRIPTION TOTAL CARRYING VALUE AT DECEMBER 31, 2023 QUOTED PRICES IN SIGNIFICANT OTHER SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) (2) Money Market Funds $ 68,008 $ — $ 68,008 $ — Time Deposits 15,913 — 15,913 — Trading Securities 9,952 6,149 3,803 — Derivative Assets 6,359 — 6,359 — Derivative Liabilities 5,769 — 5,769 — Deferred Purchase Obligations (1) 208,265 — — 208,265 (1) Primarily relates to the fair values of the deferred purchase obligations associated with the ITRenew Transaction (as defined in Note 3 to Notes to Consolidated Financial Statements included in our Annual Report) and the Regency Transaction (as defined in Note 3). (2) The following is a rollforward of the Level 3 liabilities presented above for December 31, 2023 through March 31, 2024: Balance as of December 31, 2023 $ 208,265 Additions 63,600 Payments (158,677) Other changes, including accretion 283 Balance as of March 31, 2024 $ 113,471 The level 3 valuations of the deferred purchase obligations were determined utilizing Monte-Carlo models and take into account our forecasted projections as they relate to the underlying performance of the respective businesses. The Monte-Carlo simulation model applied in assessing the fair value of the deferred purchase obligation associated with the ITRenew Transaction incorporates assumptions as to expected gross profits over the achievement period, including adjustments for the volatility of timing and amount of the associated revenue and costs, as well as discount rates that account for the risk of the arrangement and overall market risks. The Monte-Carlo simulation model applied in assessing the fair value of the deferred purchase obligation associated with the Regency Transaction incorporates assumptions as to expected revenue over the achievement period, including adjustments for volatility and timing, as well as discount rates that account for the risk of the arrangement and overall market risks. Any material change to these assumptions may result in a significantly higher or lower fair value of the related deferred purchase obligation. There were no material items that were measured at fair value on a non-recurring basis at March 31, 2024 and December 31, 2023 other than (i) those disclosed in Note 2.p. to Notes to Consolidated Financial Statements included in our Annual Report and (ii) assets acquired and liabilities assumed through our acquisitions that occurred during the three months ended March 31, 2024 (see Note 3), both of which are based on Level 3 inputs. F. ACCUMULATED OTHER COMPREHENSIVE ITEMS, NET The changes in Accumulated other comprehensive items, net for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FOREIGN DERIVATIVE FINANCIAL TOTAL FOREIGN DERIVATIVE FINANCIAL TOTAL Beginning of Period $ (373,628) $ 2,472 $ (371,156) $ (454,509) $ 12,506 $ (442,003) Other comprehensive (loss) income: Foreign currency translation and other adjustments (66,501) — (66,501) 39,677 — 39,677 Change in fair value of derivative instruments — 11,388 11,388 — (3,442) (3,442) Reclassifications from accumulated other comprehensive items, net — (2,528) (2,528) — — — Total other comprehensive (loss) income (66,501) 8,860 (57,641) 39,677 (3,442) 36,235 End of Period $ (440,129) $ 11,332 $ (428,797) $ (414,832) $ 9,064 $ (405,768) G. REVENUES The costs associated with the initial movement of customer records into physical storage and certain commissions are considered costs to fulfill or obtain customer contracts (collectively, "Contract Costs"). Contract Costs as of March 31, 2024 and December 31, 2023 are as follows: MARCH 31, 2024 DECEMBER 31, 2023 GROSS ACCUMULATED NET GROSS ACCUMULATED NET Intake Costs asset $ 76,233 $ (38,593) $ 37,640 $ 76,150 $ (39,617) $ 36,533 Commissions asset 171,254 (66,803) 104,451 156,639 (64,279) 92,360 Deferred revenue liabilities are reflected in our Condensed Consolidated Balance Sheets as follows: DESCRIPTION LOCATION IN BALANCE SHEET MARCH 31, 2024 DECEMBER 31, 2023 Deferred revenue - Current Deferred revenue $ 332,801 $ 325,665 Deferred revenue - Long-term Other Long-term Liabilities 97,075 100,770 DATA CENTER LESSOR CONSIDERATIONS Our Global Data Center Business features storage rental provided to customers at contractually specified rates over a fixed contractual period, which are accounted for in accordance with Accounting Standards Codification 842. Storage rental revenue associated with our Global Data Center Business for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Storage rental revenue $ 140,028 $ 107,435 H. STOCK-BASED COMPENSATION Our stock-based compensation expense includes the cost of stock options, restricted stock units ("RSUs") and performance units ("PUs") (together, the "Employee Stock-Based Awards"). STOCK-BASED COMPENSATION EXPENSE Stock-based compensation expense for the Employee Stock-Based Awards for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Stock-based compensation expense $ 14,039 $ 12,509 In March 2024, we granted approximately 83,100, 582,800 and 444,000 stock options, RSUs and PUs, respectively, under the 2014 Plan (as defined in Note 2.t to Notes to Consolidated Financial Statements included in our Annual Report). As of March 31, 2024, unrecognized compensation cost related to the unvested portion of our Employee Stock-Based Awards, inclusive of our estimated achievement of the performance metrics, is $132,940. I. ACQUISITION AND INTEGRATION COSTS Acquisition and integration costs represent operating expenditures directly associated with the closing and integration activities of our business acquisitions that have closed, or are highly probable of closing, and include (i) advisory, legal and professional fees to complete business acquisitions and (ii) costs to integrate acquired businesses into our existing operations, including move, severance and system integration costs (collectively, "Acquisition and Integration Costs"). Acquisition and Integration Costs for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Acquisition and Integration Costs $ 7,809 $ 1,595 J. LOSS (GAIN) ON DISPOSAL/WRITE-DOWN OF PROPERTY, PLANT AND EQUIPMENT, NET Loss (gain) on disposal/write-down of property, plant and equipment, net for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 (1) Loss (gain) on disposal/write-down of property, plant and equipment, net $ 389 $ (13,061) (1) The gains for the three months ended March 31, 2023 primarily consist of a gain of approximately $18,500 associated with a sale-leaseback transaction of a facility in Singapore. The gains recognized during 2023 are the result of our program to monetize a small portion of our industrial assets through sale and sale-leaseback transactions. The terms for these leases are consistent with the terms of our lease portfolio, which are disclosed in detail in Note 2.j. to Notes to Consolidated Financial Statements included in our Annual Report. K. OTHER (INCOME) EXPENSE, NET Other (income) expense, net for the three months ended March 31, 2024 and 2023 consists of the following: THREE MONTHS ENDED MARCH 31, DESCRIPTION 2024 2023 Foreign currency transaction (gains) losses, net $ (16,379) $ 14,424 Other, net 3,849 6,776 Other (Income) Expense, Net $ (12,530) $ 21,200 L. INCOME TAXES We provide for income taxes during interim periods based on our estimate of the effective tax rate for the year. Our effective tax rates for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Effective Tax Rate (1) 17.7 % 20.4 % (1) The primary reconciling items between the federal statutory tax rate of 21.0% and our overall effective tax rate for the three months ended March 31, 2024 and 2023 were the benefits derived from the dividends paid deduction and the differences in the tax rates to which our foreign earnings are subject. M. INCOME (LOSS) PER SHARE—BASIC AND DILUTED The calculations of basic and diluted income (loss) per share for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Net Income (Loss) $ 77,025 $ 65,535 Less: Net Income (Loss) Attributable to Noncontrolling Interests 2,964 940 Net Income (Loss) Attributable to Iron Mountain Incorporated (utilized in numerator of Earnings Per Share calculation) $ 74,061 $ 64,595 Weighted-average shares—basic 292,746,000 291,442,000 Effect of dilutive potential stock options 1,886,000 1,216,000 Effect of dilutive potential RSUs and PUs 589,000 391,000 Weighted-average shares—diluted 295,221,000 293,049,000 Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $ 0.25 $ 0.22 Diluted $ 0.25 $ 0.22 Antidilutive stock options, RSUs and PUs excluded from the calculation 365,764 145,730

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Acquisitions	ACQUISITIONS REGENCY TECHNOLOGIES On January 3, 2024, in order to expand our asset lifecycle management ("ALM") business, we acquired 100% of RSR Partners, LLC (doing business as Regency Technologies), an information technology asset disposition services provider with operations throughout the United States, for an initial purchase price of approximately $200,000, with $125,000 paid at closing, funded by borrowings under the Revolving Credit Facility (as defined in Note 6), and the remaining $75,000 (the “January 2025 Payment”) to be paid in January 2025 (the "Regency Transaction"). The present value of the January 2025 Payment is included as a component of Accrued expenses and other current liabilities in our Condensed Consolidated Balance Sheet at March 31, 2024. The agreement for the Regency Transaction also includes a performance-based contingent consideration with a potential earnout range from zero to $200,000 based upon achievement of certain three-year cumulative revenue targets, which would be payable in 2027, if earned (the “Regency Deferred Purchase Obligation”). The preliminary fair value estimate of the Regency Deferred Purchase Obligation as of the date of the acquisition is approximately $78,400. The present value of the Regency Deferred Purchase Obligation is included as a component of Other Long-term Liabilities in our Condensed Consolidated Balance Sheet at March 31, 2024. Subsequent increases or decreases in the fair value estimate of the Regency Deferred Purchase Obligation, as well as the accretion of the discount to present value, will be included as a component of Other (income) expense, net in our Condensed Consolidated Statements of Operations until the deferred purchase obligation is settled or paid. Subsequent to the acquisition, the results of Regency Technologies are included as a component of Corporate and Other. PRELIMINARY PURCHASE PRICE ALLOCATION A summary of the cumulative consideration paid and the preliminary allocation of the purchase price paid for all of our acquisitions closed during the three months ended March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 Cash Paid (gross of cash acquired) $ 125,000 Deferred Purchase Obligations, Purchase Price Holdbacks and Other (1) 133,713 Total Consideration 258,713 Fair Value of Identifiable Assets Acquired (2) 155,259 Fair Value of Identifiable Liabilities Acquired (28,241) Goodwill Initially Recorded (3) $ 131,695 (1) Consists of the acquisition-date present values of the Regency Deferred Purchase Obligation and the January 2025 Payment. (2) Assets acquired include a customer and supplier relationship intangible asset, which has a fair value of $108,000 and a weighted average life of approximately 20 years. (3) Goodwill is primarily attributable to the assembled workforce, expanded market opportunities and costs and other operating synergies anticipated upon the integration of the operations of us and the acquired businesses. The preliminary purchase price allocations that are not finalized as of March 31, 2024 relate to the final assessment of the fair values of property, plant and equipment and intangible assets associated with the acquisitions we closed during the three months ended March 31, 2024. Any adjustments to our estimates of purchase price allocation will be made in the periods in which the adjustments are determined, and the cumulative effect of such adjustments will be calculated as if the adjustments had been completed as of the acquisition dates. Purchase price allocation adjustments recorded during the three months ended March 31, 2024 were not material to our balance sheet or results from operations.

Investments

Investments	3 Months Ended
	Mar. 31, 2024
Investments, All Other Investments [Abstract]
Investments	JOINT VENTURE SUMMARY Our joint venture with AGC Equity Partners (the "Frankfurt JV") is accounted for as an equity method investment and is presented as a component of Other within Other assets, net in our Condensed Consolidated Balance Sheets. The carrying value and equity interest in the Frankfurt JV at March 31, 2024 and December 31, 2023 is as follows: MARCH 31, 2024 DECEMBER 31, 2023 CARRYING VALUE EQUITY INTEREST CARRYING VALUE EQUITY INTEREST Frankfurt JV $ 55,757 20 % $ 57,874 20 %

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Derivative instruments we are party to include: (i) interest rate swap agreements (which are designated as cash flow hedges) and (ii) cross-currency swap agreements (which are designated as net investment hedges). INTEREST RATE SWAP AGREEMENTS DESIGNATED AS CASH FLOW HEDGES We utilize interest rate swap agreements designated as cash flow hedges to limit our exposure to changes in interest rates on a portion of our floating rate indebtedness. Certain of our interest rate swap agreements have notional amounts that will increase with the underlying hedged transaction. Under our interest rate swap agreements, we receive variable rate interest payments associated with the notional amount of each interest rate swap, based upon the one-month Secured Overnight Financing Rate, in exchange for the payment of fixed interest rates as specified in the interest rate swap agreements. Our interest rate swap agreements are marked to market at the end of each reporting period, representing the fair values of the interest rate swap agreements, and any changes in fair value are recognized as a component of Accumulated other comprehensive items, net. Unrealized gains are recognized as assets, while unrealized losses are recognized as liabilities. As of March 31, 2024 and December 31, 2023, we have approximately $1,104,000 and $520,000, respectively, in notional value outstanding on our interest rate swap agreements, with maturity dates ranging from October 2025 through February 2027. CROSS-CURRENCY SWAP AGREEMENTS DESIGNATED AS A HEDGE OF NET INVESTMENT We utilize cross-currency interest rate swaps to hedge the variability of exchange rate impacts between the United States dollar and the Euro. As of both March 31, 2024 and December 31, 2023, we have approximately $509,200 in notional value outstanding on cross-currency interest rate swaps, with maturity dates ranging from August 2024 through February 2026. We have designated these cross-currency swap agreements as hedges of net investments in certain of our Euro denominated subsidiaries and they require an exchange of the notional amounts at maturity. These cross-currency swap agreements are marked to market at the end of each reporting period, representing the fair values of the cross-currency swap agreements, and any changes in fair value are recognized as a component of Accumulated other comprehensive items, net. Unrealized gains are recognized as assets while unrealized losses are recognized as liabilities. The excluded component of our cross-currency swap agreements is recorded in Accumulated other comprehensive items, net and amortized to interest expense on a straight-line basis. The fair values of derivative instruments recognized in our Condensed Consolidated Balance Sheets at March 31, 2024 and December 31, 2023, by derivative instrument, are as follows: MARCH 31, 2024 DECEMBER 31, 2023 DERIVATIVE INSTRUMENTS (1) Assets Liabilities Assets Liabilities Cash Flow Hedges (2) Interest rate swap agreements $ 9,716 $ — $ 1,601 $ (3,273) Net Investment Hedges (3) Cross-currency swap agreements 10,574 — 4,758 (2,496) (1) Our derivative assets are included as a component of (i) Prepaid expenses and other or (ii) Other within Other assets, net and our derivative liabilities are included as a component of (i) Accrued expenses and other current liabilities or (ii) Other long-term liabilities in our Condensed Consolidated Balance Sheets. As of March 31, 2024, $1,086 is included within Prepaid expenses and other and $19,204 is included within Other assets. As of December 31, 2023, $6,359 is included within Other assets, $2,496 is included within Accrued expenses and other liabilities and $3,273 is included within Other long-term liabilities. (2) As of March 31, 2024, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our interest rate swap agreements are $11,332. (3) As of March 31, 2024, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our cross-currency swap agreements are $44,947, which include $34,373 related to the excluded component of our cross-currency swap agreements. Unrealized gains (losses) recognized in Accumulated other comprehensive items, net during the three months ended March 31, 2024 and 2023, by derivative instrument, are as follows: THREE MONTHS ENDED MARCH 31, DERIVATIVE INSTRUMENTS 2024 2023 Cash Flow Hedges Interest rate swap agreements $ 11,388 $ (3,442) Net Investment Hedges Cross-currency swap agreements 8,312 (8,803) Cross-currency swap agreements (excluded component) 4,176 5,834 Gains (losses) recognized in Net income (loss) during the three months ended March 31, 2024 and 2023, by derivative instrument, are as follows: THREE MONTHS ENDED MARCH 31, DERIVATIVE INSTRUMENTS Location of gain (loss) 2024 2023 Cash Flow Hedges Interest rate swap agreements Interest expense $ 2,528 $ — Net Investment Hedges Cross-currency swap agreements (excluded component) Interest expense (4,176) (5,834)

Debt

Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	DEBT Long-term debt is as follows: MARCH 31, 2024 DECEMBER 31, 2023 DEBT (INCLUSIVE OF DISCOUNT) UNAMORTIZED DEFERRED FINANCING COSTS CARRYING AMOUNT FAIR VALUE DEBT (INCLUSIVE OF DISCOUNT) UNAMORTIZED DEFERRED FINANCING COSTS CARRYING AMOUNT FAIR VALUE Revolving Credit Facility (1) $ 660,000 $ (4,265) $ 655,735 $ 660,000 $ — $ (4,621) $ (4,621) $ — Term Loan A (1) 225,000 — 225,000 225,000 228,125 — 228,125 228,125 Term Loan B due 2026 (1) 657,605 (2,186) 655,419 658,000 659,298 (2,498) 656,800 659,750 Term Loan B due 2031 (1) 1,188,318 (12,610) 1,175,708 1,197,000 1,191,000 (13,026) 1,177,974 1,200,000 Virginia 3 Term Loans (2) 165,555 (4,206) 161,349 165,555 101,218 (4,641) 96,577 101,218 Virginia 4/5 Term Loans (2) 49,994 (5,089) 44,905 49,994 16,338 (5,892) 10,446 16,338 Australian Dollar Term Loan (2) 188,064 (426) 187,638 189,327 197,743 (482) 197,261 199,195 UK Bilateral Revolving Credit Facility (2) 176,737 — 176,737 176,737 178,239 — 178,239 178,239 GBP Notes (2) 504,963 (1,510) 503,453 487,809 509,254 (1,763) 507,491 489,108 4 7 / 8 % Notes due 2027 (2) 1,000,000 (4,976) 995,024 960,000 1,000,000 (5,332) 994,668 967,500 5 1 / 4 % Notes due 2028 (2) 825,000 (4,724) 820,276 794,063 825,000 (5,019) 819,981 800,250 5% Notes due 2028 (2) 500,000 (3,135) 496,865 476,250 500,000 (3,316) 496,684 478,750 7% Notes due 2029 (2) 1,000,000 (10,281) 989,719 1,015,000 1,000,000 (10,813) 989,187 1,027,500 4 7 / 8 % Notes due 2029 (2) 1,000,000 (7,956) 992,044 932,500 1,000,000 (8,318) 991,682 945,000 5 1 / 4 % Notes due 2030 (2) 1,300,000 (9,527) 1,290,473 1,225,250 1,300,000 (9,903) 1,290,097 1,241,500 4 1 / 2 % Notes (2) 1,100,000 (8,607) 1,091,393 987,250 1,100,000 (8,917) 1,091,083 995,500 5% Notes due 2032 (2) 750,000 (10,880) 739,120 682,500 750,000 (11,206) 738,794 684,375 5 5 / 8 % Notes (2) 600,000 (4,840) 595,160 567,000 600,000 (4,985) 595,015 567,000 Real Estate Mortgages, Financing Lease Liabilities and Other 552,265 (678) 551,587 552,265 519,907 (403) 519,504 519,907 Accounts Receivable Securitization Program 360,000 (265) 359,735 360,000 358,500 (317) 358,183 358,183 Total Long-term Debt 12,803,501 (96,161) 12,707,340 12,034,622 (101,452) 11,933,170 Less Current Portion (118,771) — (118,771) (120,670) — (120,670) Long-term Debt, Net of Current Portion $ 12,684,730 $ (96,161) $ 12,588,569 $ 11,913,952 $ (101,452) $ 11,812,500 (1) Collectively, the “Credit Agreement”. The Credit Agreement consists of a revolving credit facility (the “Revolving Credit Facility”), a term loan A facility (the “Term Loan A”) and two term loan B facilities (the "Term Loan B due 2026" and the "Term Loan B due 2031"). The Revolving Credit Facility and the Term Loan A are scheduled to mature on March 18, 2027. The Term Loan B due 2026 is scheduled to mature on January 2, 2026. The Term Loan B due 2031 is scheduled to mature on January 31, 2031. The remaining amount available for borrowing under the Revolving Credit Facility as of March 31, 2024 was $1,585,174 (which represents the maximum availability as of such date). The weighted average interest rate in effect under the Revolving Credit Facility was 7.3% as of March 31, 2024. (2) Each as defined in Note 7 to Notes to Consolidated Financial Statements included in our Annual Report. See Note 7 to Notes to Consolidated Financial Statements included in our Annual Report for additional information regarding our long-term debt, including the direct obligors of each of our debt instruments as well as information regarding the fair value of our debt instruments (including the levels of the fair value hierarchy used to determine the fair value of our debt instruments, which are consistent with the levels of the fair value hierarchy used to determine the fair value of our debt as of March 31, 2024). LETTERS OF CREDIT As of March 31, 2024, we had outstanding letters of credit totaling $38,796, of which $4,826 reduce our borrowing capacity under the Revolving Credit Facility. The letters of credit expire at various dates between May 2024 and April 2025. DEBT COVENANTS The Credit Agreement, our bond indentures and other agreements governing our indebtedness contain certain restrictive financial and operating covenants, including covenants that restrict our ability to complete acquisitions, pay cash dividends, incur indebtedness, make investments, sell assets and take other specified corporate actions. The covenants do not contain a rating trigger. Therefore, a change in our debt rating would not trigger a default under the Credit Agreement, our bond indentures or other agreements governing our indebtedness. The Credit Agreement requires that we satisfy a net total lease adjusted leverage ratio and a fixed charge coverage ratio on a quarterly basis, and our bond indentures require that, among other things, we satisfy a leverage ratio (not lease adjusted) or a fixed charge coverage ratio (not lease adjusted) as a condition to taking actions such as paying dividends and incurring indebtedness. The Credit Agreement uses earnings before interest, taxes, depreciation and amortization and rent expense ("EBITDAR") based calculations and the bond indentures use earnings before interest, taxes, depreciation and amortization ("EBITDA") based calculations as the primary measures of financial performance for purposes of calculating leverage and fixed charge coverage ratios. The EBITDAR- and EBITDA-based leverage calculations include our consolidated subsidiaries, other than those we have designated as "Unrestricted Subsidiaries" as defined in the Credit Agreement and bond indentures. Generally, the Credit Agreement and the bond indentures use a trailing four fiscal quarter basis for purposes of the relevant calculations and require certain adjustments and exclusions for purposes of those calculations, which make the calculation of financial performance for purposes of those calculations under the Credit Agreement and bond indentures not directly comparable to Adjusted EBITDA as presented herein. We are in compliance with our leverage and fixed charge coverage ratios under the Credit Agreement, our bond indentures and other agreements governing our indebtedness as of March 31, 2024. Noncompliance with these leverage and fixed charge coverage ratios would have a material adverse effect on our financial condition and liquidity.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES We are involved in litigation from time to time in the ordinary course of business, including litigation arising from damage to customer assets in our facilities caused by fires and other natural disasters. While the outcome of litigation is inherently uncertain, we do not believe any current litigation will have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We have estimated a reasonably possible range for all loss contingencies and believe it is reasonably possible that we could incur aggregate losses in addition to amounts currently accrued for all matters up to an additional $15,000 over the next several years, of which certain amounts would be covered by insurance or indemnity arrangement.

Stockholders' Equity Matters

Stockholders' Equity Matters	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Stockholders' Equity Matters	STOCKHOLDERS' EQUITY MATTERS In fiscal year 2023 and the three months ended March 31, 2024, our board of directors declared the following dividends: DECLARATION DATE DIVIDEND RECORD DATE TOTAL PAYMENT DATE February 23, 2023 $ 0.6185 March 15, 2023 $ 180,339 April 5, 2023 May 4, 2023 0.6185 June 15, 2023 180,493 July 6, 2023 August 3, 2023 0.6500 September 15, 2023 189,730 October 5, 2023 November 2, 2023 0.6500 December 15, 2023 189,886 January 4, 2024 February 22, 2024 0.6500 March 15, 2024 190,506 April 4, 2024 On May 2, 2024, we declared a dividend to our stockholders of record as of June 17, 2024 of $0.65 per share, payable on July 5, 2024.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION Our reportable segments as of December 31, 2023 are described in Note 11 to Notes to Consolidated Financial Statements included in our Annual Report and are as follows: • Global RIM Business • Global Data Center Business The remaining activities of our business consist primarily of our Fine Arts and ALM businesses and other corporate items ("Corporate and Other"). The operations associated with acquisitions completed during the first three months of 2024 have been incorporated into our existing reportable segments. An analysis of our business segment information and reconciliation to the accompanying Condensed Consolidated Financial Statements for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Global RIM Business Total Revenues $ 1,210,157 $ 1,126,526 Adjusted EBITDA 526,268 477,784 Global Data Center Business Total Revenues $ 143,937 $ 112,305 Adjusted EBITDA 61,568 50,635 Corporate and Other Total Revenues $ 122,769 $ 75,518 Adjusted EBITDA (68,981) (67,611) Total Consolidated Total Revenues $ 1,476,863 $ 1,314,349 Adjusted EBITDA 518,855 460,808 Adjusted EBITDA for each segment is defined as net income (loss) before interest expense, net, provision (benefit) for income taxes, depreciation and amortization (inclusive of our share of Adjusted EBITDA from our unconsolidated joint ventures), and excluding certain items we do not believe to be indicative of our core operating results, specifically: EXCLUDED • Acquisition and Integration Costs • Restructuring and other transformation • Loss (gain) on disposal/write-down of property, plant and equipment, net (including real estate) • Other (income) expense, net • Stock-based compensation expense Internally, we use Adjusted EBITDA as the basis for evaluating the performance of, and allocating resources to, our operating segments. A reconciliation of Net Income (Loss) to Adjusted EBITDA on a consolidated basis for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Net Income (Loss) $ 77,025 $ 65,535 Add/(Deduct): Interest expense, net 164,519 137,169 Provision (benefit) for income taxes 16,609 16,758 Depreciation and amortization 209,555 182,094 Acquisition and Integration Costs 7,809 1,595 Restructuring and other transformation 40,767 36,913 Loss (gain) on disposal/write-down of property, plant and equipment, net (including real estate) 389 (13,061) Other (income) expense, net, excluding our share of losses (gains) from our unconsolidated joint ventures (13,110) 17,491 Stock-based compensation expense 14,039 12,509 Our share of Adjusted EBITDA reconciling items from our unconsolidated joint ventures 1,253 3,805 Adjusted EBITDA $ 518,855 $ 460,808 Information as to our revenues by product and service lines by segment for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Global RIM Business Records Management (1) $ 936,652 $ 867,988 Data Management (1) 132,050 129,594 Information Destruction (1)(2) 141,455 128,944 Data Center (1) — — Global Data Center Business Records Management (1) $ — $ — Data Management (1) — — Information Destruction (1) — — Data Center (1) 143,937 112,305 Corporate and Other Records Management (1) $ 39,072 $ 34,348 Data Management (1) — — Information Destruction (1)(3) 83,697 41,170 Data Center (1) — — Total Consolidated Records Management (1) $ 975,724 $ 902,336 Data Management (1) 132,050 129,594 Information Destruction (1)(2)(3) 225,152 170,114 Data Center (1) 143,937 112,305 (1) Each of these offerings has a component of revenue that is storage rental related and a component that is service related, except for information destruction, which does not have a storage rental component. (2) Information destruction revenue for our Global RIM Business includes secure shredding services. (3) Information destruction revenue for Corporate and Other includes product revenue from our ALM business.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Parties	In October 2020, in connection with the formation of the Frankfurt JV, we entered into agreements whereby we earn various fees, including (i) special project revenue and (ii) property management and construction and development fees for services we are providing to the Frankfurt JV (the "Frankfurt JV Agreements"). In February 2022, we entered into a storage and service agreement with the joint venture formed by Clutter, Inc. and us (the "Clutter JV") to provide certain storage and related services to the Clutter JV (the "Clutter Agreement"). On June 29, 2023, we completed the Clutter Acquisition (as defined in Note 3 to Notes to Consolidated Financial Statements included in our Annual Report) and terminated the Clutter Agreement. Revenue recognized in the accompanying Condensed Consolidated Statements of Operations under these agreements for the three months ended March 31, 2024 and 2023 is as follows (approximately): THREE MONTHS ENDED MARCH 31, 2024 2023 Frankfurt JV Agreements (1) $ 400 $ 900 Clutter Agreement (2) — 6,000 (1) Revenue associated with the Frankfurt JV Agreements is presented as a component of our Global Data Center Business segment. (2) Revenue associated with the Clutter Agreement is presented as a component of our Global RIM Business segment.

Restructuring And Other Transfo

Restructuring And Other Transformation	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Restructuring And Other Transformation	RESTRUCTURING AND OTHER TRANSFORMATION PROJECT MATTERHORN In September 2022, we announced Project Matterhorn. Project Matterhorn investments focus on transforming our operating model to a global operating model. Project Matterhorn focuses on the formation of a solution-based sales approach that is designed to allow us to optimize our shared services and best practices to better serve our customers' needs. We are investing to accelerate growth and to capture a greater share of the large, global addressable markets in which we operate. We expect to incur approximately $150,000 in costs annually related to Project Matterhorn from 2023 through 2025. Costs are comprised of (1) restructuring costs, which include (i) site consolidation and other related exit costs, (ii) employee severance costs and (iii) certain professional fees associated with these activities and (2) other transformation costs, which include professional fees such as project management costs and costs for third party consultants who are assisting in the enablement of our growth initiatives. Restructuring and other transformation related to Project Matterhorn included in the accompanying Condensed Consolidated Statement of Operations for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN Restructuring $ 10,726 $ 11,957 $ 81,337 Other transformation 30,041 24,956 176,578 Restructuring and other transformation $ 40,767 $ 36,913 $ 257,915 Restructuring costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Condensed Consolidated Statement of Operations, by segment, for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN Global RIM Business $ 10,141 $ 9,525 $ 69,946 Global Data Center Business 4 78 524 Corporate and Other 581 2,354 10,867 Total restructuring costs $ 10,726 $ 11,957 $ 81,337 Other transformation costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Condensed Consolidated Statement of Operations, by segment, for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN THROUGH MARCH 31, 2024 Global RIM Business $ 8,970 $ 3,485 $ 41,240 Global Data Center Business 1,391 870 6,413 Corporate and Other 19,680 20,601 128,925 Total other transformation costs $ 30,041 $ 24,956 $ 176,578 The rollforward of the accrued restructuring costs and accrued other transformation costs, which are included as components of Accrued expenses and other current liabilities in our Condensed Consolidated Balance Sheets, for December 31, 2023 through March 31, 2024 is as follows: RESTRUCTURING OTHER TRANSFORMATION TOTAL RESTRUCTURING AND OTHER TRANSFORMATION Balance as of December 31, 2023 $ 10,731 $ 24,854 $ 35,585 Amount accrued 10,726 30,041 40,767 Payments (13,321) (38,241) (51,562) Balance as of March 31, 2024 $ 8,136 $ 16,654 $ 24,790

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Mr. John Tomovcsik [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 6, 2024, Mr. John Tomovcsik, our Executive Vice President and Chief Operating Officer, adopted a 10b5-1 trading plan to sell up to 35,084 shares of our common stock between June 20, 2024 and June 18, 2025. Mr. Tomovcsik’s plan will terminate on the earlier of (i) June 18, 2025 and (ii) the date that all trades under the plan are completed.
Name	Mr. John Tomovcsik
Title	Executive Vice President and Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 6, 2024
Arrangement Duration	363 days
Aggregate Available	35,084
Mr. Greg McIntosh [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 14, 2024, Mr. Greg McIntosh, our Executive Vice President and Chief Commercial Officer, Global Records and Information Management, adopted a 10b5-1 trading plan to exercise options to purchase up to 3,923 shares of our common stock and sell up to 13,923 shares of our common stock between June 13, 2024 and June 28, 2024. Mr. McIntosh’s plan will terminate on the earlier of (i) June 28, 2024 and (ii) the date that all trades under the plan are completed.
Name	Mr. Greg McIntosh
Title	Executive Vice President and Chief Commercial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 14, 2024
Arrangement Duration	15 days
Mr. Daniel Borges [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 15, 2024, Mr. Daniel Borges, our Senior Vice President and Chief Accounting Officer, adopted a 10b5-1 trading plan to sell up to 6,837 shares of our common stock between June 17, 2024 and May 30, 2025, including (i) 100% of the (net) shares to be acquired upon vesting of his 2022 and 2023 restricted stock units and (ii) 100% of the (net) shares to be acquired upon vesting of his 2022 performance units, as adjusted based on actual results. Net shares are net of tax withholding. Mr. Borges’ plan will terminate on the earlier of (i) May 30, 2025 and (ii) the date that all trades under the plan are completed.
Name	Mr. Daniel Borges
Title	Senior Vice President and Chief Accounting Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 15, 2024
Arrangement Duration	347 days
Aggregate Available	6,837
Mr. Barry Hytinen [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 20, 2024, Mr. Barry Hytinen, our Executive Vice President and Chief Financial Officer, adopted a 10b5-1 trading plan to sell up to 9,000 shares of our common stock between June 18, 2024 and June 18, 2025. Mr. Hytinen’s plan will terminate on the earlier of (i) June 18, 2025 and (ii) the date that all trades under the plan are completed.
Name	Mr. Barry Hytinen
Title	Executive Vice President and Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 20, 2024
Arrangement Duration	365 days
Aggregate Available	9,000
Mr. Edward Greene [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 21, 2024, Mr. Edward Greene, our Executive Vice President and Chief Human Resources Officer, adopted a 10b5-1 trading plan to sell up to 8,462 shares of our common stock between June 20, 2024 and December 31, 2024. Mr. Greene’s plan will terminate on the earlier of (i) December 31, 2024 and (ii) the date that all trades under the plan are completed.
Name	Mr. Edward Greene
Title	Executive Vice President and Chief Human Resources Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 21, 2024
Arrangement Duration	194 days
Aggregate Available	8,462
Purchase Common Stock [Member] | Mr. Greg McIntosh [Member]
Trading Arrangements, by Individual
Aggregate Available	3,923
Sell Common Stock [Member] | Mr. Greg McIntosh [Member]
Trading Arrangements, by Individual
Aggregate Available	13,923

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Cash and Cash Equivalents	CASH AND CASH EQUIVALENTS Cash and cash equivalents include cash on hand and cash invested in highly liquid short-term securities, which have remaining maturities at the date of purchase of less than 90 days. Cash and cash equivalents are carried at cost, which approximates fair value.
Accounts Receivable	ACCOUNTS RECEIVABLE We maintain an allowance for doubtful accounts and a credit memo reserve for estimated losses resulting from the potential inability of our customers to make required payments and potential disputes regarding billing and service issues.
Leases	LEASES We lease facilities for certain warehouses, data centers and office space. We also have land leases, including those on which certain facilities are located.
Fair Value Measurements	The level 3 valuations of the deferred purchase obligations were determined utilizing Monte-Carlo models and take into account our forecasted projections as they relate to the underlying performance of the respective businesses. The Monte-Carlo simulation model applied in assessing the fair value of the deferred purchase obligation associated with the ITRenew Transaction incorporates assumptions as to expected gross profits over the achievement period, including adjustments for the volatility of timing and amount of the associated revenue and costs, as well as discount rates that account for the risk of the arrangement and overall market risks. The Monte-Carlo simulation model applied in assessing the fair value of the deferred purchase obligation associated with the Regency Transaction incorporates assumptions as to expected revenue over the achievement period, including adjustments for volatility and timing, as well as discount rates that account for the risk of the arrangement and overall market risks. Any material change to these assumptions may result in a significantly higher or lower fair value of the related deferred purchase obligation.
Revenues	REVENUESThe costs associated with the initial movement of customer records into physical storage and certain commissions are considered costs to fulfill or obtain customer contracts (collectively, "Contract Costs"). DATA CENTER LESSOR CONSIDERATIONS
Acquisition and Integration Costs	ACQUISITION AND INTEGRATION COSTSAcquisition and integration costs represent operating expenditures directly associated with the closing and integration activities of our business acquisitions that have closed, or are highly probable of closing, and include (i) advisory, legal and professional fees to complete business acquisitions and (ii) costs to integrate acquired businesses into our existing operations, including move, severance and system integration costs (collectively, "Acquisition and Integration Costs").
Income Taxes	INCOME TAXESWe provide for income taxes during interim periods based on our estimate of the effective tax rate for the year.
Commitments and Contingencies	We are involved in litigation from time to time in the ordinary course of business, including litigation arising from damage to customer assets in our facilities caused by fires and other natural disasters. While the outcome of litigation is inherently uncertain, we do not believe any current litigation will have a material adverse effect on our consolidated financial condition, results of operations or cash flows.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Schedule of Allowance for Credit Loss	The rollforward of the allowance for doubtful accounts and credit memo reserves for the three months ended March 31, 2024 is as follows: Balance as of December 31, 2023 $ 74,762 Credit memos charged to revenue 24,035 Allowance for bad debts charged to expense 14,338 Deductions and other (1) (35,722) Balance as of March 31, 2024 $ 77,413 (1) Primarily consists of the issuance of credit memos, the write-off of accounts receivable and the impact associated with currency translation adjustments.
Schedule of Operating and Financing Lease Right-of-Use Assets and Lease Liabilities	Operating and financing lease right-of-use assets and lease liabilities as of March 31, 2024 and December 31, 2023 are as follows: DESCRIPTION MARCH 31, 2024 DECEMBER 31, 2023 Assets: Operating lease right-of-use assets $ 2,677,803 $ 2,696,024 Financing lease right-of-use assets, net of accumulated depreciation (1) 318,753 304,600 Liabilities: Current Operating lease liabilities $ 301,344 $ 291,795 Financing lease liabilities (1) 39,973 39,089 Long-term Operating lease liabilities $ 2,525,552 $ 2,562,394 Financing lease liabilities (1) 323,653 310,776 (1) Financing lease right-of-use assets, current financing lease liabilities and long-term financing lease liabilities are included within Property, plant and equipment, net, Current portion of long-term debt and Long-term debt, net of current portion, respectively, within our Condensed Consolidated Balance Sheets.
Schedule of Lease Costs and Other Information	The components of the lease expense for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, DESCRIPTION 2024 2023 Operating lease cost (1) $ 171,746 $ 155,873 Financing lease cost: Depreciation of financing lease right-of-use assets $ 10,944 $ 10,008 Interest expense for financing lease liabilities 5,221 4,341 (1) Operating lease cost, the majority of which is included in Cost of sales, includes variable lease costs of $38,094 and $31,580 for the three months ended March 31, 2024 and 2023, respectively. THREE MONTHS ENDED MARCH 31, CASH PAID FOR AMOUNTS INCLUDED IN MEASUREMENT OF LEASE LIABILITIES: 2024 2023 Operating cash flows used in operating leases $ 117,336 $ 108,723 Operating cash flows used in financing leases (interest) 5,221 4,341 Financing cash flows used in financing leases 10,679 11,714 NON-CASH ITEMS: Operating lease modifications and reassessments $ (262) $ 18,163 New operating leases (including acquisitions and sale-leaseback transactions) 64,556 113,853
Schedule of Changes in the Carrying Value of Goodwill Attributable to Each Reportable Operating Segment	The changes in the carrying value of goodwill attributable to each reportable segment and Corporate and Other (as defined in Note 9) for the three months ended March 31, 2024 are as follows: GLOBAL RIM BUSINESS GLOBAL DATA CENTER BUSINESS CORPORATE AND OTHER TOTAL CONSOLIDATED Goodwill balance, net of accumulated amortization, as of December 31, 2023 $ 3,911,945 $ 478,930 $ 627,037 $ 5,017,912 Tax deductible goodwill acquired during the period — — 131,695 131,695 Fair value and other adjustments 143 (186) — (43) Currency effects (38,502) (2,995) (594) (42,091) Goodwill balance, net of accumulated amortization, as of March 31, 2024 $ 3,873,586 $ 475,749 $ 758,138 $ 5,107,473 Accumulated goodwill impairment balance as of March 31, 2024 $ 132,409 $ — $ 26,011 $ 158,420
Schedule of Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis	The assets and liabilities carried at fair value measured on a recurring basis as of March 31, 2024 and December 31, 2023 are as follows: FAIR VALUE MEASUREMENTS AT MARCH 31, 2024 USING DESCRIPTION TOTAL CARRYING VALUE AT MARCH 31, 2024 QUOTED PRICES IN SIGNIFICANT OTHER SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) (2) Money Market Funds $ 6,027 $ — $ 6,027 $ — Time Deposits 32,014 — 32,014 — Trading Securities 10,662 6,783 3,879 — Derivative Assets 20,290 — 20,290 — Deferred Purchase Obligations (1) 113,471 — — 113,471 FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2023 USING DESCRIPTION TOTAL CARRYING VALUE AT DECEMBER 31, 2023 QUOTED PRICES IN SIGNIFICANT OTHER SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) (2) Money Market Funds $ 68,008 $ — $ 68,008 $ — Time Deposits 15,913 — 15,913 — Trading Securities 9,952 6,149 3,803 — Derivative Assets 6,359 — 6,359 — Derivative Liabilities 5,769 — 5,769 — Deferred Purchase Obligations (1) 208,265 — — 208,265 (1) Primarily relates to the fair values of the deferred purchase obligations associated with the ITRenew Transaction (as defined in Note 3 to Notes to Consolidated Financial Statements included in our Annual Report) and the Regency Transaction (as defined in Note 3). (2) The following is a rollforward of the Level 3 liabilities presented above for December 31, 2023 through March 31, 2024: Balance as of December 31, 2023 $ 208,265 Additions 63,600 Payments (158,677) Other changes, including accretion 283 Balance as of March 31, 2024 $ 113,471
Schedule of Changes in Accumulated Other Comprehensive Items, Net	The changes in Accumulated other comprehensive items, net for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FOREIGN DERIVATIVE FINANCIAL TOTAL FOREIGN DERIVATIVE FINANCIAL TOTAL Beginning of Period $ (373,628) $ 2,472 $ (371,156) $ (454,509) $ 12,506 $ (442,003) Other comprehensive (loss) income: Foreign currency translation and other adjustments (66,501) — (66,501) 39,677 — 39,677 Change in fair value of derivative instruments — 11,388 11,388 — (3,442) (3,442) Reclassifications from accumulated other comprehensive items, net — (2,528) (2,528) — — — Total other comprehensive (loss) income (66,501) 8,860 (57,641) 39,677 (3,442) 36,235 End of Period $ (440,129) $ 11,332 $ (428,797) $ (414,832) $ 9,064 $ (405,768)
Schedule of Cost and Accumulated Amortization Associated with Contract Fulfillment Costs	Contract Costs as of March 31, 2024 and December 31, 2023 are as follows: MARCH 31, 2024 DECEMBER 31, 2023 GROSS ACCUMULATED NET GROSS ACCUMULATED NET Intake Costs asset $ 76,233 $ (38,593) $ 37,640 $ 76,150 $ (39,617) $ 36,533 Commissions asset 171,254 (66,803) 104,451 156,639 (64,279) 92,360
Schedule of Deferred Revenue Liabilities	Deferred revenue liabilities are reflected in our Condensed Consolidated Balance Sheets as follows: DESCRIPTION LOCATION IN BALANCE SHEET MARCH 31, 2024 DECEMBER 31, 2023 Deferred revenue - Current Deferred revenue $ 332,801 $ 325,665 Deferred revenue - Long-term Other Long-term Liabilities 97,075 100,770
Schedule of Revenue	Storage rental revenue associated with our Global Data Center Business for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Storage rental revenue $ 140,028 $ 107,435
Schedule of Stock-based Compensation Expense	Stock-based compensation expense for the Employee Stock-Based Awards for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Stock-based compensation expense $ 14,039 $ 12,509
Schedule of Acquisition and Integration Costs	Acquisition and Integration Costs for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Acquisition and Integration Costs $ 7,809 $ 1,595
Schedule of Loss (Gain) on Disposal/Write-Down of Property, Plant and Equipment, Net	Loss (gain) on disposal/write-down of property, plant and equipment, net for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 (1) Loss (gain) on disposal/write-down of property, plant and equipment, net $ 389 $ (13,061) (1) The gains for the three months ended March 31, 2023 primarily consist of a gain of approximately $18,500 associated with a sale-leaseback transaction of a facility in Singapore. The gains recognized during 2023 are the result of our program to monetize a small portion of our industrial assets through sale and sale-leaseback transactions. The terms for these leases are consistent with the terms of our lease portfolio, which are disclosed in detail in Note 2.j. to Notes to Consolidated Financial Statements included in our Annual Report.
Schedule of Other (Income) Expense, Net	Other (income) expense, net for the three months ended March 31, 2024 and 2023 consists of the following: THREE MONTHS ENDED MARCH 31, DESCRIPTION 2024 2023 Foreign currency transaction (gains) losses, net $ (16,379) $ 14,424 Other, net 3,849 6,776 Other (Income) Expense, Net $ (12,530) $ 21,200
Schedule of Income Taxes	Our effective tax rates for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Effective Tax Rate (1) 17.7 % 20.4 % (1)
Schedule of Basic and Diluted Net Income (Loss) Per Share Attributable to the Entity	The calculations of basic and diluted income (loss) per share for the three months ended March 31, 2024 and 2023 are as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Net Income (Loss) $ 77,025 $ 65,535 Less: Net Income (Loss) Attributable to Noncontrolling Interests 2,964 940 Net Income (Loss) Attributable to Iron Mountain Incorporated (utilized in numerator of Earnings Per Share calculation) $ 74,061 $ 64,595 Weighted-average shares—basic 292,746,000 291,442,000 Effect of dilutive potential stock options 1,886,000 1,216,000 Effect of dilutive potential RSUs and PUs 589,000 391,000 Weighted-average shares—diluted 295,221,000 293,049,000 Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated: Basic $ 0.25 $ 0.22 Diluted $ 0.25 $ 0.22 Antidilutive stock options, RSUs and PUs excluded from the calculation 365,764 145,730

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Schedule of recognized identified assets acquired and liabilities assumed	A summary of the cumulative consideration paid and the preliminary allocation of the purchase price paid for all of our acquisitions closed during the three months ended March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 Cash Paid (gross of cash acquired) $ 125,000 Deferred Purchase Obligations, Purchase Price Holdbacks and Other (1) 133,713 Total Consideration 258,713 Fair Value of Identifiable Assets Acquired (2) 155,259 Fair Value of Identifiable Liabilities Acquired (28,241) Goodwill Initially Recorded (3) $ 131,695 (1) Consists of the acquisition-date present values of the Regency Deferred Purchase Obligation and the January 2025 Payment. (2) Assets acquired include a customer and supplier relationship intangible asset, which has a fair value of $108,000 and a weighted average life of approximately 20 years. (3) Goodwill is primarily attributable to the assembled workforce, expanded market opportunities and costs and other operating synergies anticipated upon the integration of the operations of us and the acquired businesses.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, All Other Investments [Abstract]
Schedule of Equity Method Investments	The carrying value and equity interest in the Frankfurt JV at March 31, 2024 and December 31, 2023 is as follows: MARCH 31, 2024 DECEMBER 31, 2023 CARRYING VALUE EQUITY INTEREST CARRYING VALUE EQUITY INTEREST Frankfurt JV $ 55,757 20 % $ 57,874 20 %

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The fair values of derivative instruments recognized in our Condensed Consolidated Balance Sheets at March 31, 2024 and December 31, 2023, by derivative instrument, are as follows: MARCH 31, 2024 DECEMBER 31, 2023 DERIVATIVE INSTRUMENTS (1) Assets Liabilities Assets Liabilities Cash Flow Hedges (2) Interest rate swap agreements $ 9,716 $ — $ 1,601 $ (3,273) Net Investment Hedges (3) Cross-currency swap agreements 10,574 — 4,758 (2,496) (1) Our derivative assets are included as a component of (i) Prepaid expenses and other or (ii) Other within Other assets, net and our derivative liabilities are included as a component of (i) Accrued expenses and other current liabilities or (ii) Other long-term liabilities in our Condensed Consolidated Balance Sheets. As of March 31, 2024, $1,086 is included within Prepaid expenses and other and $19,204 is included within Other assets. As of December 31, 2023, $6,359 is included within Other assets, $2,496 is included within Accrued expenses and other liabilities and $3,273 is included within Other long-term liabilities. (2) As of March 31, 2024, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our interest rate swap agreements are $11,332. (3) As of March 31, 2024, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our cross-currency swap agreements are $44,947, which include $34,373 related to the excluded component of our cross-currency swap agreements.
Schedule of Gains (Losses) for Derivative Instruments	Unrealized gains (losses) recognized in Accumulated other comprehensive items, net during the three months ended March 31, 2024 and 2023, by derivative instrument, are as follows: THREE MONTHS ENDED MARCH 31, DERIVATIVE INSTRUMENTS 2024 2023 Cash Flow Hedges Interest rate swap agreements $ 11,388 $ (3,442) Net Investment Hedges Cross-currency swap agreements 8,312 (8,803) Cross-currency swap agreements (excluded component) 4,176 5,834 Gains (losses) recognized in Net income (loss) during the three months ended March 31, 2024 and 2023, by derivative instrument, are as follows: THREE MONTHS ENDED MARCH 31, DERIVATIVE INSTRUMENTS Location of gain (loss) 2024 2023 Cash Flow Hedges Interest rate swap agreements Interest expense $ 2,528 $ — Net Investment Hedges Cross-currency swap agreements (excluded component) Interest expense (4,176) (5,834)

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Carrying Amount and Fair Value of Long-Term Debt Instruments	Long-term debt is as follows: MARCH 31, 2024 DECEMBER 31, 2023 DEBT (INCLUSIVE OF DISCOUNT) UNAMORTIZED DEFERRED FINANCING COSTS CARRYING AMOUNT FAIR VALUE DEBT (INCLUSIVE OF DISCOUNT) UNAMORTIZED DEFERRED FINANCING COSTS CARRYING AMOUNT FAIR VALUE Revolving Credit Facility (1) $ 660,000 $ (4,265) $ 655,735 $ 660,000 $ — $ (4,621) $ (4,621) $ — Term Loan A (1) 225,000 — 225,000 225,000 228,125 — 228,125 228,125 Term Loan B due 2026 (1) 657,605 (2,186) 655,419 658,000 659,298 (2,498) 656,800 659,750 Term Loan B due 2031 (1) 1,188,318 (12,610) 1,175,708 1,197,000 1,191,000 (13,026) 1,177,974 1,200,000 Virginia 3 Term Loans (2) 165,555 (4,206) 161,349 165,555 101,218 (4,641) 96,577 101,218 Virginia 4/5 Term Loans (2) 49,994 (5,089) 44,905 49,994 16,338 (5,892) 10,446 16,338 Australian Dollar Term Loan (2) 188,064 (426) 187,638 189,327 197,743 (482) 197,261 199,195 UK Bilateral Revolving Credit Facility (2) 176,737 — 176,737 176,737 178,239 — 178,239 178,239 GBP Notes (2) 504,963 (1,510) 503,453 487,809 509,254 (1,763) 507,491 489,108 4 7 / 8 % Notes due 2027 (2) 1,000,000 (4,976) 995,024 960,000 1,000,000 (5,332) 994,668 967,500 5 1 / 4 % Notes due 2028 (2) 825,000 (4,724) 820,276 794,063 825,000 (5,019) 819,981 800,250 5% Notes due 2028 (2) 500,000 (3,135) 496,865 476,250 500,000 (3,316) 496,684 478,750 7% Notes due 2029 (2) 1,000,000 (10,281) 989,719 1,015,000 1,000,000 (10,813) 989,187 1,027,500 4 7 / 8 % Notes due 2029 (2) 1,000,000 (7,956) 992,044 932,500 1,000,000 (8,318) 991,682 945,000 5 1 / 4 % Notes due 2030 (2) 1,300,000 (9,527) 1,290,473 1,225,250 1,300,000 (9,903) 1,290,097 1,241,500 4 1 / 2 % Notes (2) 1,100,000 (8,607) 1,091,393 987,250 1,100,000 (8,917) 1,091,083 995,500 5% Notes due 2032 (2) 750,000 (10,880) 739,120 682,500 750,000 (11,206) 738,794 684,375 5 5 / 8 % Notes (2) 600,000 (4,840) 595,160 567,000 600,000 (4,985) 595,015 567,000 Real Estate Mortgages, Financing Lease Liabilities and Other 552,265 (678) 551,587 552,265 519,907 (403) 519,504 519,907 Accounts Receivable Securitization Program 360,000 (265) 359,735 360,000 358,500 (317) 358,183 358,183 Total Long-term Debt 12,803,501 (96,161) 12,707,340 12,034,622 (101,452) 11,933,170 Less Current Portion (118,771) — (118,771) (120,670) — (120,670) Long-term Debt, Net of Current Portion $ 12,684,730 $ (96,161) $ 12,588,569 $ 11,913,952 $ (101,452) $ 11,812,500 (1) Collectively, the “Credit Agreement”. The Credit Agreement consists of a revolving credit facility (the “Revolving Credit Facility”), a term loan A facility (the “Term Loan A”) and two term loan B facilities (the "Term Loan B due 2026" and the "Term Loan B due 2031"). The Revolving Credit Facility and the Term Loan A are scheduled to mature on March 18, 2027. The Term Loan B due 2026 is scheduled to mature on January 2, 2026. The Term Loan B due 2031 is scheduled to mature on January 31, 2031. The remaining amount available for borrowing under the Revolving Credit Facility as of March 31, 2024 was $1,585,174 (which represents the maximum availability as of such date). The weighted average interest rate in effect under the Revolving Credit Facility was 7.3% as of March 31, 2024. (2) Each as defined in Note 7 to Notes to Consolidated Financial Statements included in our Annual Report.

Stockholders' Equity Matters (T

Stockholders' Equity Matters (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Dividend Declared and Payments	In fiscal year 2023 and the three months ended March 31, 2024, our board of directors declared the following dividends: DECLARATION DATE DIVIDEND RECORD DATE TOTAL PAYMENT DATE February 23, 2023 $ 0.6185 March 15, 2023 $ 180,339 April 5, 2023 May 4, 2023 0.6185 June 15, 2023 180,493 July 6, 2023 August 3, 2023 0.6500 September 15, 2023 189,730 October 5, 2023 November 2, 2023 0.6500 December 15, 2023 189,886 January 4, 2024 February 22, 2024 0.6500 March 15, 2024 190,506 April 4, 2024

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Analysis of Business Segment Information	An analysis of our business segment information and reconciliation to the accompanying Condensed Consolidated Financial Statements for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Global RIM Business Total Revenues $ 1,210,157 $ 1,126,526 Adjusted EBITDA 526,268 477,784 Global Data Center Business Total Revenues $ 143,937 $ 112,305 Adjusted EBITDA 61,568 50,635 Corporate and Other Total Revenues $ 122,769 $ 75,518 Adjusted EBITDA (68,981) (67,611) Total Consolidated Total Revenues $ 1,476,863 $ 1,314,349 Adjusted EBITDA 518,855 460,808
Schedule of Reconciliation of Net Income (Loss) to Adjusted EBITDA	A reconciliation of Net Income (Loss) to Adjusted EBITDA on a consolidated basis for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Net Income (Loss) $ 77,025 $ 65,535 Add/(Deduct): Interest expense, net 164,519 137,169 Provision (benefit) for income taxes 16,609 16,758 Depreciation and amortization 209,555 182,094 Acquisition and Integration Costs 7,809 1,595 Restructuring and other transformation 40,767 36,913 Loss (gain) on disposal/write-down of property, plant and equipment, net (including real estate) 389 (13,061) Other (income) expense, net, excluding our share of losses (gains) from our unconsolidated joint ventures (13,110) 17,491 Stock-based compensation expense 14,039 12,509 Our share of Adjusted EBITDA reconciling items from our unconsolidated joint ventures 1,253 3,805 Adjusted EBITDA $ 518,855 $ 460,808
Schedule of Revenues by Product and Service Lines by Segment	Information as to our revenues by product and service lines by segment for the three months ended March 31, 2024 and 2023 is as follows: THREE MONTHS ENDED MARCH 31, 2024 2023 Global RIM Business Records Management (1) $ 936,652 $ 867,988 Data Management (1) 132,050 129,594 Information Destruction (1)(2) 141,455 128,944 Data Center (1) — — Global Data Center Business Records Management (1) $ — $ — Data Management (1) — — Information Destruction (1) — — Data Center (1) 143,937 112,305 Corporate and Other Records Management (1) $ 39,072 $ 34,348 Data Management (1) — — Information Destruction (1)(3) 83,697 41,170 Data Center (1) — — Total Consolidated Records Management (1) $ 975,724 $ 902,336 Data Management (1) 132,050 129,594 Information Destruction (1)(2)(3) 225,152 170,114 Data Center (1) 143,937 112,305 (1) Each of these offerings has a component of revenue that is storage rental related and a component that is service related, except for information destruction, which does not have a storage rental component. (2) Information destruction revenue for our Global RIM Business includes secure shredding services. (3) Information destruction revenue for Corporate and Other includes product revenue from our ALM business.

Related Parties (Tables)

Related Parties (Tables)	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Schedule of Revenue Recognized	Revenue recognized in the accompanying Condensed Consolidated Statements of Operations under these agreements for the three months ended March 31, 2024 and 2023 is as follows (approximately): THREE MONTHS ENDED MARCH 31, 2024 2023 Frankfurt JV Agreements (1) $ 400 $ 900 Clutter Agreement (2) — 6,000 (1) Revenue associated with the Frankfurt JV Agreements is presented as a component of our Global Data Center Business segment. (2) Revenue associated with the Clutter Agreement is presented as a component of our Global RIM Business segment.

Restructuring And Other Trans_2

Restructuring And Other Transformation (Tables)	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Schedule of Restructuring And Other Transformation	Restructuring and other transformation related to Project Matterhorn included in the accompanying Condensed Consolidated Statement of Operations for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN Restructuring $ 10,726 $ 11,957 $ 81,337 Other transformation 30,041 24,956 176,578 Restructuring and other transformation $ 40,767 $ 36,913 $ 257,915 Restructuring costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Condensed Consolidated Statement of Operations, by segment, for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN Global RIM Business $ 10,141 $ 9,525 $ 69,946 Global Data Center Business 4 78 524 Corporate and Other 581 2,354 10,867 Total restructuring costs $ 10,726 $ 11,957 $ 81,337 Other transformation costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Condensed Consolidated Statement of Operations, by segment, for the three months ended March 31, 2024 and 2023 and from the inception of Project Matterhorn through March 31, 2024 is as follows: THREE MONTHS ENDED MARCH 31, 2024 THREE MONTHS ENDED MARCH 31, 2023 FROM INCEPTION OF PROJECT MATTERHORN THROUGH MARCH 31, 2024 Global RIM Business $ 8,970 $ 3,485 $ 41,240 Global Data Center Business 1,391 870 6,413 Corporate and Other 19,680 20,601 128,925 Total other transformation costs $ 30,041 $ 24,956 $ 176,578 The rollforward of the accrued restructuring costs and accrued other transformation costs, which are included as components of Accrued expenses and other current liabilities in our Condensed Consolidated Balance Sheets, for December 31, 2023 through March 31, 2024 is as follows: RESTRUCTURING OTHER TRANSFORMATION TOTAL RESTRUCTURING AND OTHER TRANSFORMATION Balance as of December 31, 2023 $ 10,731 $ 24,854 $ 35,585 Amount accrued 10,726 30,041 40,767 Payments (13,321) (38,241) (51,562) Balance as of March 31, 2024 $ 8,136 $ 16,654 $ 24,790

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Allowance for Doubtful Accounts and Credit Memo Reserves (Details) - Allowance for doubtful accounts $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 74,762
Credit memos charged to revenue	24,035
Allowance for bad debts charged to expense	14,338
Deductions and other	(35,722)
Ending balance	$ 77,413

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Operating lease right-of-use assets	$ 2,677,803	$ 2,696,024
Financing lease right-of-use assets, net of accumulated depreciation	318,753	304,600
Current
Operating lease liabilities	301,344	291,795
Finance lease liabilities	39,973	39,089
Long-term
Operating lease liabilities	2,525,552	2,562,394
Finance lease liabilities	$ 323,653	$ 310,776
Finance lease, right-of-use asset, statement of financial position [Extensible List]	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Operating lease, liability, current, statement of financial position [Extensible List]	Accrued expenses and other current liabilities (includes current portion of operating lease liabilities)	Accrued expenses and other current liabilities (includes current portion of operating lease liabilities)
Finance lease, liability, current, statement of financial position [Extensible List]	Current portion of long-term debt	Current portion of long-term debt
Finance lease, liability, noncurrent, statement of financial position [Extensible List]	Long-term Debt, net of current portion	Long-term Debt, net of current portion

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Leases Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounting Policies [Abstract]
Operating lease cost	$ 171,746	$ 155,873
Depreciation of financing lease right-of-use assets	10,944	10,008
Interest expense for financing lease liabilities	5,221	4,341
Variable lease costs	$ 38,094	$ 31,580

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Supplemental Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounting Policies [Abstract]
Operating cash flows used in operating leases	$ 117,336	$ 108,723
Operating cash flows used in financing leases (interest)	5,221	4,341
Financing cash flows used in financing leases	10,679	11,714
Operating lease modifications and reassessments	(262)	18,163
New operating leases (including acquisitions and sale-leaseback transactions)	$ 64,556	$ 113,853

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Schedule of Changes in Carrying Value of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Gross amount of goodwill [Roll Forward]
Goodwill beginning balance	$ 5,017,912
Tax deductible goodwill acquired during the period	131,695
Fair value and other adjustments	(43)
Currency effects	(42,091)
Goodwill ending balance	5,107,473
Accumulated goodwill impairment	158,420
GLOBAL RIM BUSINESS
Gross amount of goodwill [Roll Forward]
Goodwill beginning balance	3,911,945
Tax deductible goodwill acquired during the period	0
Fair value and other adjustments	143
Currency effects	(38,502)
Goodwill ending balance	3,873,586
Accumulated goodwill impairment	132,409
GLOBAL DATA CENTER BUSINESS
Gross amount of goodwill [Roll Forward]
Goodwill beginning balance	478,930
Tax deductible goodwill acquired during the period	0
Fair value and other adjustments	(186)
Currency effects	(2,995)
Goodwill ending balance	475,749
Accumulated goodwill impairment	0
CORPORATE AND OTHER
Gross amount of goodwill [Roll Forward]
Goodwill beginning balance	627,037
Tax deductible goodwill acquired during the period	131,695
Fair value and other adjustments	0
Currency effects	(594)
Goodwill ending balance	758,138
Accumulated goodwill impairment	$ 26,011

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Deferred Purchase Obligations
Deferred Purchase Obligations [Roll Forward]
Balance as of December 31, 2023	$ 208,265
Additions	63,600
Payments	(158,677)
Other changes, including accretion	283
Balance as of March 31, 2024	113,471
Fair Value, Measurements, Recurring | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Trading Securities	6,783	$ 6,149
Derivative Assets	0	0
Derivative Liabilities		0
Deferred purchase obligations	0	0
Fair Value, Measurements, Recurring | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) | Money Market Funds
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) | Time Deposits
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Trading Securities	3,879	3,803
Derivative Assets	20,290	6,359
Derivative Liabilities		5,769
Deferred purchase obligations	0	0
Fair Value, Measurements, Recurring | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Money Market Funds
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	6,027	68,008
Fair Value, Measurements, Recurring | SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Time Deposits
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	32,014	15,913
Fair Value, Measurements, Recurring | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Trading Securities	0	0
Derivative Assets	0	0
Derivative Liabilities		0
Deferred purchase obligations	113,471	208,265
Fair Value, Measurements, Recurring | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Money Market Funds
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Time Deposits
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring | Estimate of Fair Value
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Trading Securities	10,662	9,952
Derivative Assets	20,290	6,359
Derivative Liabilities		5,769
Deferred purchase obligations	113,471	208,265
Fair Value, Measurements, Recurring | Estimate of Fair Value | Money Market Funds
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	6,027	68,008
Fair Value, Measurements, Recurring | Estimate of Fair Value | Time Deposits
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Cash and cash equivalents	$ 32,014	$ 15,913

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income and Other Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Rollforward
Beginning of Period	$ 211,773	$ 636,793
Other comprehensive (loss) income:
Foreign currency translation and other adjustments	(66,501)	39,677
Change in fair value of derivative instruments	11,388	(3,442)
Reclassifications from accumulated other comprehensive items, net	(2,528)	0
Total other comprehensive (loss) income	(57,641)	36,235
End of Period	18,660	545,589
TOTAL
AOCI Rollforward
Beginning of Period	(371,156)	(442,003)
Other comprehensive (loss) income:
End of Period	(428,797)	(405,768)
FOREIGN CURRENCY TRANSLATION AND OTHER ADJUSTMENTS
AOCI Rollforward
Beginning of Period	(373,628)	(454,509)
Other comprehensive (loss) income:
Foreign currency translation and other adjustments	(66,501)	39,677
Change in fair value of derivative instruments	0	0
Reclassifications from accumulated other comprehensive items, net	0	0
Total other comprehensive (loss) income	(66,501)	39,677
End of Period	(440,129)	(414,832)
DERIVATIVE FINANCIAL INSTRUMENTS
AOCI Rollforward
Beginning of Period	2,472	12,506
Other comprehensive (loss) income:
Foreign currency translation and other adjustments	0	0
Change in fair value of derivative instruments	11,388	(3,442)
Reclassifications from accumulated other comprehensive items, net	(2,528)	0
Total other comprehensive (loss) income	8,860	(3,442)
End of Period	$ 11,332	$ 9,064

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Contract Fulfillment Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Intake Costs asset
Contract With Customer, Asset And Liabilities [Line Items]
GROSS CARRYING AMOUNT	$ 76,233	$ 76,150
ACCUMULATED AMORTIZATION	(38,593)	(39,617)
NET CARRYING AMOUNT	37,640	36,533
Commissions asset
Contract With Customer, Asset And Liabilities [Line Items]
GROSS CARRYING AMOUNT	171,254	156,639
ACCUMULATED AMORTIZATION	(66,803)	(64,279)
NET CARRYING AMOUNT	$ 104,451	$ 92,360

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Summary of Deferred Revenue Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Deferred revenue - Current	$ 332,801	$ 325,665
Deferred revenue - Long-term	$ 97,075	$ 100,770

Summary of Significant Accou_13

Summary of Significant Accounting Policies - Storage Rental (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lessor, Lease, Description [Line Items]
Storage rental revenue	$ 1,476,863	$ 1,314,349
GLOBAL DATA CENTER BUSINESS
Lessor, Lease, Description [Line Items]
Storage rental revenue	143,937	112,305
Storage rental
Lessor, Lease, Description [Line Items]
Storage rental revenue	884,842	810,089
Storage rental | GLOBAL DATA CENTER BUSINESS
Lessor, Lease, Description [Line Items]
Storage rental revenue	$ 140,028	$ 107,435

Summary of Significant Accou_14

Summary of Significant Accounting Policies - Stock-Based Compensation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2024	Mar. 31, 2023
Employee Stock-Based Awards
Stock-based compensation expense		$ 14,039	$ 12,509
Stock options granted (in shares)	83,100
Unrecognized compensation cost	$ 132,940	$ 132,940
Restricted Stock Units
Employee Stock-Based Awards
Granted (in shares)	582,800
Performance units
Employee Stock-Based Awards
Granted (in shares)	444,000

Summary of Significant Accou_15

Summary of Significant Accounting Policies - Acquisition and Integration costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounting Policies [Abstract]
Acquisition and Integration Costs	$ 7,809	$ 1,595

Summary of Significant Accou_16

Summary of Significant Accounting Policies - Loss (Gain) on Disposal/Write-Down of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss (gain) on disposal/write-down of property, plant and equipment, net	$ 389	$ (13,061)
Facilities in Singapore
Accumulated Other Comprehensive Income (Loss) [Line Items]
Sale and sale-leaseback transactions		$ 18,500

Summary of Significant Accou_17

Summary of Significant Accounting Policies - Other (Income) Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounting Policies [Abstract]
Foreign currency transaction (gains) losses, net	$ (16,379)	$ 14,424
Other, net	3,849	6,776
Other (Income) Expense, Net	$ (12,530)	$ 21,200

Summary of Significant Accou_18

Summary of Significant Accounting Policies - Income Taxes (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounting Policies [Abstract]
Effective tax rate	17.70%	20.40%
Federal statutory tax rate	21%	21%

Summary of Significant Accou_19

Summary of Significant Accounting Policies - Income (Loss) Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income (Loss) Per Share-Basic and Diluted
Net Income (Loss)	$ 77,025	$ 65,535
Less: Net Income (Loss) Attributable to Noncontrolling Interests	2,964	940
Net Income (Loss) Attributable to Iron Mountain Incorporated (utilized in numerator of Earnings Per Share calculation)	$ 74,061	$ 64,595
Weighted-average shares—basic (in shares)	292,746,000	291,442,000
Effect of dilutive potential stock options (in shares)	1,886,000	1,216,000
Effect of dilutive potential RSUs and PUs (in shares)	589,000	391,000
Weighted-average shares—diluted (in shares)	295,221,000	293,049,000
Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated:
Basic (in dollars per share)	$ 0.25	$ 0.22
Diluted (in dollars per share)	$ 0.25	$ 0.22
Antidilutive stock options, RSUs and PUs, excluded from the calculation (in shares)	365,764	145,730

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - RSR Partners, LLC - USD ($)		1 Months Ended
	Jan. 03, 2024	Jan. 31, 2025
Business Acquisition [Line Items]
Total consideration	$ 200,000,000
Cash Paid (gross of cash acquired)	125,000,000
Regency Deferred Purchase Obligation
Business Acquisition [Line Items]
Value of possible subsequent acquisition, low	0
Value of possible subsequent acquisition, high	200,000,000
Contingent consideration liability	$ 78,400,000
Forecast
Business Acquisition [Line Items]
Cash Paid (gross of cash acquired)		$ 75,000,000

Acquisitions - Schedule of Purc

Acquisitions - Schedule of Purchase Price Allocation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Business Acquisition [Line Items]
Goodwill initially recorded	$ 5,107,473	$ 5,017,912
Year To Date Acquisitions
Business Acquisition [Line Items]
Cash Paid (gross of cash acquired)	125,000
Deferred Purchase Obligations, Purchase Price Holdbacks and Other	133,713
Total Consideration	258,713
Fair Value of Identifiable Assets Acquired	155,259
Fair Value of Identifiable Liabilities Acquired	(28,241)
Goodwill initially recorded	131,695
Customer Relationships | Year To Date Acquisitions
Business Acquisition [Line Items]
Customer and supplier relationship intangible assets	$ 108
Acquired finite-lived intangible assets, weighted average useful life	20 years

Investments - Schedule of Equit

Investments - Schedule of Equity Method Investments (Details) - Frankfurt JV - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
CARRYING VALUE	$ 55,757	$ 57,874
EQUITY INTEREST	20%	20%

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Interest rate swap agreements
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 1,104,000	$ 520,000
Cross-currency Swap Agreements | Net Investment Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 509,200	$ 509,200

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest rate swap agreements
Derivative [Line Items]
Interest rate swap agreements	$ 2,528	$ 0
Cross-currency swap agreements | Net Investment Hedges
Derivative [Line Items]
Cross-currency swap agreements (excluded component)	(4,176)	(5,834)
Designated as Hedging Instrument | Interest rate swap agreements
Derivative [Line Items]
Interest rate swap agreements	11,388	(3,442)
Designated as Hedging Instrument | Cross-currency swap agreements
Derivative [Line Items]
Cross-currency swap agreements	8,312	(8,803)
Not Designated as Hedging Instrument | Cross-currency swap agreements
Derivative [Line Items]
Cross-currency swap agreements	$ 4,176	$ 5,834

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities - Net Assets (Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative asset, current	$ 1,086
Derivative asset, noncurrent	$ 19,204	$ 6,359
Derivative liability, current		2,496
Derivative liability, noncurrent		3,273
Derivative liability, statement of financial position [Extensible Enumeration]	Accrued expenses and other current liabilities (includes current portion of operating lease liabilities), Other Long-term Liabilities
Derivative asset, current, statement of financial position [Extensible Enumeration]	Prepaid expenses and other
Derivative liability, noncurrent, statement of financial position [Extensible Enumeration]	Other Long-term Liabilities
Derivative asset, statement of financial position [Extensible Enumeration]	Prepaid expenses and other, Assets, Noncurrent, Excluding Property, Plant and Equipment, Net
Derivative asset, noncurrent, statement of financial position [Extensible Enumeration]	Assets, Noncurrent, Excluding Property, Plant and Equipment, Net
Interest rate swap agreements
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative net gain in AOCI	$ 11,332
Cash Flow Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Assets	9,716	1,601
Derivative Liabilities	0	(3,273)
Net Investment Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Assets	10,574	4,758
Derivative Liabilities	0	$ (2,496)
Cumulative net gain in cross-currency swaps	44,947
Net Investment Hedges | Cross-currency swap agreements (excluded component)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative net gain in cross-currency swaps	$ 34,373

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 12,803,501	$ 12,034,622
UNAMORTIZED DEFERRED FINANCING COSTS	(96,161)	(101,452)
CARRYING AMOUNT	12,707,340	11,933,170
Debt, current portion	(118,771)	(120,670)
Unamortized debt issuance expense, net of current portion	0	0
Carrying amount, current maturities	(118,771)	(120,670)
Long term debt, gross, net of current portion	12,684,730	11,913,952
Unamortized deferred financing costs, noncurrent	(96,161)	(101,452)
Carrying amount, excluding current maturities	12,588,569	11,812,500
Accounts Receivable Securitization Program
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	360,000	358,500
UNAMORTIZED DEFERRED FINANCING COSTS	(265)	(317)
CARRYING AMOUNT	359,735	358,183
FAIR VALUE	360,000	358,183
Credit Agreement
Debt Instrument [Line Items]
Letters of credit outstanding	38,796
Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	660,000
UNAMORTIZED DEFERRED FINANCING COSTS	(4,265)
CARRYING AMOUNT	655,735
FAIR VALUE	660,000
Remaining capacity	$ 1,585,174
Weighted average interest rate (as a percent)	7.30%
Letters of credit outstanding	$ 4,826
Credit Agreement | UK Bilateral Revolving Credit Facility
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	176,737	178,239
UNAMORTIZED DEFERRED FINANCING COSTS	0	0
CARRYING AMOUNT	176,737	178,239
FAIR VALUE	176,737	178,239
Credit Agreement | Revolving Credit Facility, Netting
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)		0
UNAMORTIZED DEFERRED FINANCING COSTS		(4,621)
CARRYING AMOUNT		(4,621)
FAIR VALUE		0
Term Loan Facility | Term Loan A
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	225,000	228,125
UNAMORTIZED DEFERRED FINANCING COSTS	0	0
CARRYING AMOUNT	225,000	228,125
FAIR VALUE	225,000	228,125
Term Loan Facility | Term Loan B due 2026
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	657,605	659,298
UNAMORTIZED DEFERRED FINANCING COSTS	(2,186)	(2,498)
CARRYING AMOUNT	655,419	656,800
FAIR VALUE	658,000	659,750
Term Loan Facility | Term Loan B due 2031
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	1,188,318	1,191,000
UNAMORTIZED DEFERRED FINANCING COSTS	(12,610)	(13,026)
CARRYING AMOUNT	1,175,708	1,177,974
FAIR VALUE	1,197,000	1,200,000
Term Loan Facility | Virginia 3 Term Loans
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	165,555	101,218
UNAMORTIZED DEFERRED FINANCING COSTS	(4,206)	(4,641)
CARRYING AMOUNT	161,349	96,577
FAIR VALUE	165,555	101,218
Term Loan Facility | Virginia 4/5 Term Loans
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	49,994	16,338
UNAMORTIZED DEFERRED FINANCING COSTS	(5,089)	(5,892)
CARRYING AMOUNT	44,905	10,446
FAIR VALUE	49,994	16,338
Australian Dollar Term Loan
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	188,064	197,743
UNAMORTIZED DEFERRED FINANCING COSTS	(426)	(482)
CARRYING AMOUNT	187,638	197,261
FAIR VALUE	189,327	199,195
Senior Notes | GBP Notes
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	504,963	509,254
UNAMORTIZED DEFERRED FINANCING COSTS	(1,510)	(1,763)
CARRYING AMOUNT	503,453	507,491
FAIR VALUE	$ 487,809	489,108
Stated interest rate (as a percent)	3.875%
Senior Notes | 47/8% Notes due 2027
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 1,000,000	1,000,000
UNAMORTIZED DEFERRED FINANCING COSTS	(4,976)	(5,332)
CARRYING AMOUNT	995,024	994,668
FAIR VALUE	$ 960,000	967,500
Stated interest rate (as a percent)	4.875%
Senior Notes | 51/4% Notes due 2028
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 825,000	825,000
UNAMORTIZED DEFERRED FINANCING COSTS	(4,724)	(5,019)
CARRYING AMOUNT	820,276	819,981
FAIR VALUE	$ 794,063	800,250
Stated interest rate (as a percent)	5.25%
Senior Notes | 5% Notes due 2028
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 500,000	500,000
UNAMORTIZED DEFERRED FINANCING COSTS	(3,135)	(3,316)
CARRYING AMOUNT	496,865	496,684
FAIR VALUE	$ 476,250	478,750
Stated interest rate (as a percent)	5%
Senior Notes | 7% Notes due 2029
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 1,000,000	1,000,000
UNAMORTIZED DEFERRED FINANCING COSTS	(10,281)	(10,813)
CARRYING AMOUNT	989,719	989,187
FAIR VALUE	$ 1,015,000	1,027,500
Stated interest rate (as a percent)	7%
Senior Notes | 47/8% Notes due 2029
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 1,000,000	1,000,000
UNAMORTIZED DEFERRED FINANCING COSTS	(7,956)	(8,318)
CARRYING AMOUNT	992,044	991,682
FAIR VALUE	$ 932,500	945,000
Stated interest rate (as a percent)	4.875%
Senior Notes | 51/4% Notes due 2030
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 1,300,000	1,300,000
UNAMORTIZED DEFERRED FINANCING COSTS	(9,527)	(9,903)
CARRYING AMOUNT	1,290,473	1,290,097
FAIR VALUE	$ 1,225,250	1,241,500
Stated interest rate (as a percent)	5.25%
Senior Notes | 41/2% Notes
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 1,100,000	1,100,000
UNAMORTIZED DEFERRED FINANCING COSTS	(8,607)	(8,917)
CARRYING AMOUNT	1,091,393	1,091,083
FAIR VALUE	$ 987,250	995,500
Stated interest rate (as a percent)	4.50%
Senior Notes | 5% Notes due 2032
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 750,000	750,000
UNAMORTIZED DEFERRED FINANCING COSTS	(10,880)	(11,206)
CARRYING AMOUNT	739,120	738,794
FAIR VALUE	$ 682,500	684,375
Stated interest rate (as a percent)	5%
Senior Notes | 55/8% Notes
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 600,000	600,000
UNAMORTIZED DEFERRED FINANCING COSTS	(4,840)	(4,985)
CARRYING AMOUNT	595,160	595,015
FAIR VALUE	$ 567,000	567,000
Stated interest rate (as a percent)	5.625%
Real Estate Mortgages, Financing Lease Liabilities and Other
Debt Instrument [Line Items]
DEBT (INCLUSIVE OF DISCOUNT)	$ 552,265	519,907
UNAMORTIZED DEFERRED FINANCING COSTS	(678)	(403)
CARRYING AMOUNT	551,587	519,504
FAIR VALUE	$ 552,265	$ 519,907

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Insurance settlement
Commitments and Contingencies
Reasonably possible additional losses	$ 15,000

Stockholders' Equity Matters (D

Stockholders' Equity Matters (Details) - USD ($) $ / shares in Units, $ in Thousands

3 Months Ended

May 02, 2024

Apr. 04, 2024

Feb. 22, 2024

Jan. 04, 2024

Nov. 02, 2023

Oct. 05, 2023

Aug. 03, 2023

Jul. 06, 2023

May 04, 2023

Apr. 05, 2023

Feb. 23, 2023

Mar. 31, 2024

Mar. 31, 2023

Debt Instrument [Line Items]

Dividend per share (in dollars per share)

$ 0.6500

$ 0.6500

$ 0.6500

$ 0.6185

$ 0.6185

TOTAL AMOUNT

$ 189,886

$ 189,730

$ 180,493

$ 180,339

$ 194,496

$ 183,272

Subsequent Event

Debt Instrument [Line Items]

Dividend per share (in dollars per share)

$ 0.65

TOTAL AMOUNT

$ 190,506

Stockholders' Equity Matters -

Stockholders' Equity Matters - Additional Information (Details) - $ / shares	May 02, 2024	Feb. 22, 2024	Nov. 02, 2023	Aug. 03, 2023	May 04, 2023	Feb. 23, 2023
Debt Instrument [Line Items]
Dividend per share (in dollars per share)		$ 0.6500	$ 0.6500	$ 0.6500	$ 0.6185	$ 0.6185
Subsequent Event
Debt Instrument [Line Items]
Dividend per share (in dollars per share)	$ 0.65

Segment Information - Segment R

Segment Information - Segment Reporting Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Total Revenues	$ 1,476,863	$ 1,314,349
Adjusted EBITDA	518,855	460,808
Global RIM Business
Segment Reporting Information [Line Items]
Total Revenues	1,210,157	1,126,526
Adjusted EBITDA	526,268	477,784
Global Data Center Business
Segment Reporting Information [Line Items]
Total Revenues	143,937	112,305
Adjusted EBITDA	61,568	50,635
Corporate and Other
Segment Reporting Information [Line Items]
Total Revenues	122,769	75,518
Adjusted EBITDA	$ (68,981)	$ (67,611)

Segment Information - Reconcili

Segment Information - Reconciliation to of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconciliation to of Net Income to Adjusted EBITDA
Net Income (Loss)	$ 77,025	$ 65,535
Interest expense, net	164,519	137,169
Provision (benefit) for income taxes	16,609	16,758
Depreciation and amortization	209,555	182,094
Acquisition and Integration Costs	7,809	1,595
Restructuring and other transformation	40,767	36,913
Loss (gain) on disposal/write-down of property, plant and equipment, net (including real estate)	389	(13,061)
Other (income) expense, net, excluding our share of losses (gains) from our unconsolidated joint ventures	(13,110)	17,491
Stock-based compensation expense	14,039	12,509
Our share of Adjusted EBITDA reconciling items from our unconsolidated joint ventures	1,253	3,805
Adjusted EBITDA	$ 518,855	$ 460,808

Segment Information - Revenues

Segment Information - Revenues by Product and Service Lines by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Total Revenues	$ 1,476,863	$ 1,314,349
GLOBAL RIM BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	1,210,157	1,126,526
GLOBAL DATA CENTER BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	143,937	112,305
CORPORATE AND OTHER
Segment Reporting Information [Line Items]
Total Revenues	122,769	75,518
Records Management
Segment Reporting Information [Line Items]
Total Revenues	975,724	902,336
Records Management | GLOBAL RIM BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	936,652	867,988
Records Management | GLOBAL DATA CENTER BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	0	0
Records Management | CORPORATE AND OTHER
Segment Reporting Information [Line Items]
Total Revenues	39,072	34,348
Data Management
Segment Reporting Information [Line Items]
Total Revenues	132,050	129,594
Data Management | GLOBAL RIM BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	132,050	129,594
Data Management | GLOBAL DATA CENTER BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	0	0
Data Management | CORPORATE AND OTHER
Segment Reporting Information [Line Items]
Total Revenues	0	0
Information Destruction
Segment Reporting Information [Line Items]
Total Revenues	225,152	170,114
Information Destruction | GLOBAL RIM BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	141,455	128,944
Information Destruction | GLOBAL DATA CENTER BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	0	0
Information Destruction | CORPORATE AND OTHER
Segment Reporting Information [Line Items]
Total Revenues	83,697	41,170
Data Center
Segment Reporting Information [Line Items]
Total Revenues	143,937	112,305
Data Center | GLOBAL RIM BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	0	0
Data Center | GLOBAL DATA CENTER BUSINESS
Segment Reporting Information [Line Items]
Total Revenues	143,937	112,305
Data Center | CORPORATE AND OTHER
Segment Reporting Information [Line Items]
Total Revenues	$ 0	$ 0

Related Parties (Details)

Related Parties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Total Revenues	$ 1,476,863	$ 1,314,349
Co-venturer | Frankfurt JV Agreements
Related Party Transaction [Line Items]
Total Revenues	400	900
Co-venturer | Clutter Agreement
Related Party Transaction [Line Items]
Total Revenues	$ 0	$ 6,000

Restructuring And Other Trans_3

Restructuring And Other Transformation - Additional Information (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Project Matterhorn
Restructuring Cost and Reserve [Line Items]
Expected cost	$ 150

Restructuring And Other Trans_4

Restructuring And Other Transformation - Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended		19 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024
Restructuring Cost and Reserve [Line Items]
Restructuring and other transformation	$ 40,767	$ 36,913
Project Matterhorn
Restructuring Cost and Reserve [Line Items]
Restructuring	10,726	11,957	$ 81,337
Other transformation	30,041	24,956	176,578
Restructuring and other transformation	40,767	36,913	257,915
Project Matterhorn | GLOBAL RIM BUSINESS
Restructuring Cost and Reserve [Line Items]
Restructuring	10,141	9,525	69,946
Other transformation	8,970	3,485	41,240
Project Matterhorn | GLOBAL DATA CENTER BUSINESS
Restructuring Cost and Reserve [Line Items]
Restructuring	4	78	524
Other transformation	1,391	870	6,413
Project Matterhorn | CORPORATE AND OTHER
Restructuring Cost and Reserve [Line Items]
Restructuring	581	2,354	10,867
Other transformation	$ 19,680	$ 20,601	$ 128,925

Restructuring and Other Trans_5

Restructuring and Other Transformation - Restructuring Rollforward (Details) - Project Matterhorn $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 35,585
Amount accrued	40,767
Payments	(51,562)
Ending balance	24,790
RESTRUCTURING
Restructuring Reserve [Roll Forward]
Beginning balance	10,731
Amount accrued	10,726
Payments	(13,321)
Ending balance	8,136
OTHER TRANSFORMATION
Restructuring Reserve [Roll Forward]
Beginning balance	24,854
Amount accrued	30,041
Payments	(38,241)
Ending balance	$ 16,654

Uncategorized Items - irm-20240

Label	Element	Value
Redeemable Noncontrolling Interests [Member]
Adjustments to Additional Paid in Capital, Change in Value of Redeemable Noncontrolling Interests	irm_AdjustmentstoAdditionalPaidinCapitalChangeinValueofRedeemableNoncontrollingInterests	$ 422,000