Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
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	One Federal Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	617
Local Phone Number	535-4766
Title of 12(b) Security	Common Stock, $.01 par value per share
Trading Symbol	IRM
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 7.4
Entity Common Stock, Shares Outstanding		288,421,215
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCECertain information required in Items 10, 11, 12, 13 and 14 of Part III of this Annual Report on Form 10-K (the “Annual Report”) is incorporated by reference from our definitive Proxy Statement for our 2021 Annual Meeting of Stockholders (our “Proxy Statement”) to be filed with the Securities and Exchange Commission (the “SEC”) within 120 days after the close of the fiscal year ended December 31, 2020.
Entity Central Index Key	0001020569
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false