Summary of Significant Accounting Policies - Long Lived Assets (Details) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2020 USD ($) facility	Sep. 30, 2020 USD ($) facility	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consolidated gain on disposal/write-down of property, plant and equipment, net				$ 363,537	$ 63,824	$ 73,622
Gain on sale of real estate, net of tax			$ 63,800
Sale and sale-leaseback transactions	$ 342,100				67,800
(Gain) Loss on disposal/write-down of property, plant and equipment, net					36,000
Intangible impairments				$ 23,000	0	$ 0
Gain associated involuntary conversion			$ 8,800
14 Facilities In The United States
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale and sale-leaseback transactions	$ 265,600	$ 76,400
Number of facilities | facility	14	2
Iron Mountain Iron Cloud
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consolidated gain on disposal/write-down of property, plant and equipment, net					25,000
Intangible impairments					$ 15,700
Frankfurt JV
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on equity investment	$ 24,100