Summary of Significant Accounting Policies - Income (Loss) Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income (Loss) Per Share-Basic and Diluted
Net Income (Loss)	$ 91,391	$ 192,931	$ 158,069	$ 436,496
Less: Net Income (Loss) Attributable to Noncontrolling Interests	348	767	2,317	1,952
Net Income (Loss) Attributable to Iron Mountain Incorporated (utilized in numerator of Earnings Per Share calculation)	$ 91,043	$ 192,164	$ 155,752	$ 434,544
Weighted-average shares—basic (in shares)	292,148,000	290,937,000	291,805,000	290,673,000
Effect of dilutive potential stock options (in shares)	1,592,000	1,133,952	1,376,000	1,126,280
Effect of dilutive potential RSUs and PUs (in shares)	529,000	480,919	434,000	494,956
Weighted-average shares—diluted (in shares)	294,269,000	292,551,871	293,615,000	292,294,236
Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated:
Basic (in dollars per share)	$ 0.31	$ 0.66	$ 0.53	$ 1.49
Diluted (in dollars per share)	$ 0.31	$ 0.66	$ 0.53	$ 1.49
Antidilutive stock options, RSUs and PUs, excluded from the calculation (in shares)	16,820	220,421	106,561	403,362