Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Jul. 30, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
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
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		289,460,314
Entity Central Index Key	0001020569
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false