Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2017
Accounting Policies [Abstract]
Foreign Currency	Foreign Currency Local currencies are the functional currencies for our operations outside the United States, with the exception of certain foreign holding companies and our financing centers in Europe, whose functional currency is the United States dollar. In those instances where the local currency is the functional currency, assets and liabilities are translated at period-end exchange rates, and revenues and expenses are translated at average exchange rates for the applicable period. Resulting translation adjustments are reflected in the accumulated other comprehensive items, net component of Iron Mountain Incorporated Stockholders' Equity, Redeemable Noncontrolling Interests and Noncontrolling Interests in the accompanying Consolidated Balance Sheets. The gain or loss on foreign currency transactions, calculated as the difference between the historical exchange rate and the exchange rate at the applicable measurement date, including those related to (i) borrowings in certain foreign currencies under our Revolving Credit Facility (as defined in Note 5) and (ii) certain foreign currency denominated intercompany obligations of our foreign subsidiaries to us and between our foreign subsidiaries, which are not considered permanently invested, are included in Other (Income) Expense, Net, in the accompanying Consolidated Statements of Operations.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill Goodwill is not amortized but is reviewed annually for impairment, or more frequently if impairment indicators arise. We have selected October 1 as our annual goodwill impairment review date.
Stock-Based Compensation	Stock-Based Compensation We record stock-based compensation expense, utilizing the straight-line method, for the cost of stock options, restricted stock units ("RSUs"), performance units ("PUs") and shares of stock issued under our employee stock purchase plan ("ESPP") (together, "Employee Stock-Based Awards"). Under our various equity compensation plans, we may also grant RSUs. Our RSUs generally have a vesting period of between three and five years from the date of grant. However, RSUs granted to our non-employee directors vest immediately upon grant. All RSUs accrue dividend equivalents associated with the underlying stock as we declare dividends. Dividends will generally be paid to holders of RSUs in cash upon the vesting date of the associated RSU and will be forfeited if the RSU does not vest. The fair value of RSUs is the excess of the market price of our common stock at the date of grant over the purchase price (which is typically zero). The majority of our PUs are earned based on our performance against revenue and ROIC targets during their applicable performance period; therefore, we forecast the likelihood of achieving the predefined revenue and ROIC targets in order to calculate the expected PUs to be earned. We record a compensation charge based on either the forecasted PUs to be earned (during the performance period) or the actual PUs earned (at the three-year anniversary of the grant date) over the vesting period for each of the awards. The fair value of PUs based on our performance against revenue and ROIC targets is the excess of the market price of our common stock at the date of grant over the purchase price (which is typically zero). For PUs earned based on a market condition, we utilize a Monte Carlo simulation to fair value these awards at the date of grant, and such fair value is expensed over the three-year performance period. Under our various equity compensation plans, we may also make awards of PUs. For the majority of outstanding PUs, the number of PUs earned is determined based on our performance against predefined targets of revenue and return on invested capital ("ROIC"). The number of PUs earned may range from 0% to 200% of the initial award. The number of PUs earned is determined based on our actual performance as compared to the targets at the end of a three-year performance period. Certain PUs that we grant will be earned based on a market condition associated with the total return on our common stock in relation to either (i) a subset of the Standard & Poor's 500 Index (for certain PUs granted prior to 2017), or (ii) a subset of the MSCI United States REIT Index (for certain PUs granted in 2017), rather than the revenue and ROIC targets noted above. The number of PUs earned based on the applicable market condition may range from 0% to 200% of the initial award. All of our PUs will be settled in shares of our common stock and are subject to cliff vesting three years from the date of the original PU grant. PUs awarded to employees who terminate their employment during the three-year performance period and on or after attaining age 55 and completing 10 years of qualifying service are eligible for pro-rated vesting, subject to the actual achievement against the predefined targets or a market condition as discussed above, based on the number of full years of service completed following the grant date (but delivery of the shares remains deferred). As a result, PUs are generally expensed over the three-year performance period. All PUs accrue dividend equivalents associated with the underlying stock as we declare dividends. Dividends will generally be paid to holders of PUs in cash upon the settlement date of the associated PU and will be forfeited if the PU does not vest. We offer an ESPP in which participation is available to substantially all United States and Canadian employees who meet certain service eligibility requirements. The price for shares purchased under the ESPP is 95% of the market price of our common stock at the end of the offering period, without a look-back feature. As a result, we do not recognize compensation expense for the ESPP shares purchased.
Income (Loss) Per Share-Basic and Diluted	Income (Loss) Per Share—Basic and Diluted Basic income (loss) per common share is calculated by dividing income (loss) by the weighted average number of common shares outstanding. The calculation of diluted income (loss) per share is consistent with that of basic income (loss) per share but gives effect to all potential common shares (that is, securities such as stock options, RSUs or PUs) that were outstanding during the period, unless the effect is antidilutive.
Income Taxes	Income Taxes We provide for income taxes during interim periods based on our estimate of the effective tax rate for the year. Discrete items and changes in our estimate of the annual effective tax rate are recorded in the period they occur. Our effective tax rate is subject to variability in the future due to, among other items: (1) changes in the mix of income between our qualified REIT subsidiaries ("QRSs") and our domestic taxable REIT subsidiaries ("TRSs"), as well as among the jurisdictions in which we operate; (2) tax law changes; (3) volatility in foreign exchange gains and losses; (4) the timing of the establishment and reversal of tax reserves; and (5) our ability to utilize net operating losses that we generate.
Fair Value Measurements	g. Fair Value Measurements Our financial assets or liabilities that are carried at fair value are required to be measured using inputs from the three levels of the fair value hierarchy. A financial asset or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The three levels of the fair value hierarchy are as follows: Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date. Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). Level 3—Unobservable inputs that reflect our assumptions about the assumptions that market participants would use in pricing the asset or liability.
New Accounting Pronouncements	New Accounting Pronouncements Recently Adopted Accounting Pronouncements In January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment ("ASU 2017-04"). ASU 2017-04 modifies the process by which entities will test goodwill for impairment. Under existing GAAP, when the carrying value of a reporting unit exceeds the reporting unit’s fair value, an entity would then proceed to a “Step 2” goodwill impairment analysis, which requires calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities, as if that reporting unit had been acquired in a business combination. Under ASU 2017-04, a goodwill impairment will be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying value of the reporting unit’s goodwill. We adopted ASU 2017-04 in the first quarter of 2017 and it did not impact our consolidated financial statements. As Yet Adopted Accounting Pronouncements a. ASU 2014-09 In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 provides guidance for management to reassess revenue recognition as it relates to: (1) transfer of control, (2) variable consideration, (3) allocation of transaction price based on relative standalone selling price, (4) licenses, (5) time value of money, and (6) contract costs. ASU 2014-09 will replace the current revenue recognition criteria under GAAP, including industry-specific requirements, and provide companies with a single revenue recognition model for recognizing revenue from contracts with customers. The core principle of ASU 2014-09 is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for such goods or services. The two permitted transition methods under ASU 2014-09 are: (i) the full retrospective method, whereby ASU 2014-09 would be applied to each prior reporting period presented and the cumulative effect of adoption would be recognized at the earliest period shown, or (ii) the modified retrospective method, whereby the cumulative effect of applying ASU 2014-09 would be recognized at the date of initial application. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of ASU 2014-09 for one year, making ASU 2014-09 effective for us on January 1, 2018, with early adoption permitted as of January 1, 2017. We will adopt ASU 2014-09 as of January 1, 2018 using the modified retrospective method. During 2015, we established a project team responsible for the assessment and implementation of ASU 2014-09. We utilized a bottoms-up approach to analyze the impact of ASU 2014-09 on our contracts with customers by reviewing our current accounting policies and practices to identify potential differences that would result from applying the requirements of ASU 2014-09 to our contracts with customers. We are currently in the process of designing and implementing appropriate changes to our business processes, systems and controls to support the accounting and the financial disclosure requirements under ASU 2014-09. We have been closely monitoring the FASB activity related to specific interpretative issues pertaining to ASU 2014-09. During the second half of 2016, we substantially completed our evaluation of the potential changes resulting from the adoption of ASU 2014-09 on our accounting and the financial disclosure requirements and are now moving into the more detailed quantification of the impacts of adopting ASU 2014-09, the more significant of which are discussed below. Based on our analysis to date, we expect that the most significant impacts associated with adopting ASU 2014-09 compared to current GAAP will relate to (i) the deferral of certain commissions on our long-term storage contracts (“Accounting for Commissions”) and (ii) certain policy changes related to initial moves of physical storage, which will be subject to new cost guidance (“Accounting for Initial Moves”). i. Accounting for Commissions Under current GAAP, commissions that we pay related to our long-term storage contracts are expensed as incurred. Under ASU 2014-09, however, certain commissions will be capitalized and amortized over the period of expected earned revenue. In the year of adoption, this will result in increased intangible contract assets on our Consolidated Balance Sheet, a reduction in selling, general and administrative expenses and a corresponding increase in amortization expense (assuming consistent levels of spending up through the adoption date) on our Consolidated Statement of Operations and an increase in cash flows from operating activities and a corresponding increase in cash used for investing activities on our Consolidated Statement of Cash Flows. ii. Accounting for Initial Moves Under current GAAP, intake costs not charged to transport boxes to one of our facilities, which include labor and transportation costs, are capitalized and amortized as a component of depreciation and amortization in our Consolidated Statements of Operations. Under ASU 2014-09, however, the revenue and costs associated with all initial moves of physical storage, regardless of whether or not the services associated with such initial moves are provided to the customer at no charge, will be deferred and recognized over the period consistent with the transfer of the service to the customer to which the asset relates. In the year of adoption, this will result in decreased intangible assets and increased deferred revenue on our Consolidated Balance Sheet, a reduction in cost of sales and a corresponding increase in amortization expense (assuming consistent levels of spending up through the adoption date) on our Consolidated Statement of Operations and an increase in cash flows from operating activities and a corresponding increase in cash used for investing activities on our Consolidated Statement of Cash Flows. b. Other As Yet Adopted Accounting Pronouncements In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"). ASU 2016-01 requires that most equity investments be measured at fair value, with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 is effective for us on January 1, 2018. We do not believe that the adoption of ASU 2016-01 will have a material impact on our consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) ("ASU 2016-02"). ASU 2016-02 requires lessees to recognize assets and liabilities on the balance sheet for the rights and obligations created by all leases with terms of more than 12 months. ASU 2016-02 also will require certain qualitative and quantitative disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. ASU 2016-02 will be effective for us on January 1, 2019, with early adoption permitted. We will adopt ASU 2016-02 on January 1, 2019 and are currently evaluating the impact ASU 2016-02 will have on our consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash ("ASU 2016-18"). ASU 2016-18 provides guidance on the classification of restricted cash in the statement of cash flows. ASU 2016-18 is effective for us on January 1, 2018, with early adoption permitted and is required to be adopted on a retrospective basis. We do not believe that the adoption of ASU 2016-18 will have a material impact on our consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business ("ASU 2017-01"). ASU 2017-01 provides greater clarity on the definition of a business to assist entities in evaluating whether transactions should be accounted for as an acquisition or disposal of assets or businesses. ASU 2017-01 is effective for us on January 1, 2018, with early adoption permitted. We are currently evaluating the impact ASU 2017-01 will have on our consolidated financial statements.

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.