Basis of Presentation	3 Months Ended
Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements of the Company are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information, and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they may not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2017, are not necessarily indicative of results that may be expected for the year ending December 31, 2017. The condensed consolidated balance sheet as of December 31, 2016 has been derived from the Company’s audited financial statements as of that date, but does not include all of the information and footnotes required by GAAP for complete financial statements. For further information refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission. Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers,” which amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. ASU 2014-09 outlines a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. The new standard will become effective for annual and interim periods beginning after December 15, 2017 with early adoption permitted. The Company has determined that its property rental revenue and tenant reinsurance revenue will not be subject to the guidance in ASU 2014-09, as they qualify as lease contracts and insurance contracts, which are excluded from its scope. The Company's management fee revenue will be included in the scope of the standard. However, based on the Company's initial assessment, it appears that revenue recognized under the standard will not differ materially from revenue recognized under existing guidance. The Company continues to assess the potential impacts of ASU 2014-09. The Company anticipates adopting the standard using the modified retrospective transition method as of January 1, 2018. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which modifies the accounting for leases, intending to increase transparency and comparability of organizations by requiring balance sheet presentation of leased assets and increased financial statement disclosure of leasing arrangements. ASU 2016-02 will require entities to recognize a liability for their lease obligations and a corresponding asset representing the right to use the underlying asset over the lease term. Lease obligations are to be measured at their present value and accounted for using the effective interest method. The accounting for the leased asset will differ slightly depending on whether the agreement is deemed to be a financing or operating lease. For financing leases, the leased asset is depreciated on a straight-line basis and depreciation expense is recorded separately from the interest expense in the statements of operations, resulting in higher expense in the earlier part of the lease term. For operating leases, the depreciation and interest expense components are combined, recognized evenly over the term of the lease, and presented as a reduction to operating income. ASU 2016-02 requires that assets and liabilities be presented or disclosed separately, and requires additional disclosure of certain qualitative and quantitative information related to these lease agreements. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018. The Company is currently assessing the impact of the adoption of ASU 2016-02 on the Company’s consolidated financial statements. In March 2016, the FASB issued ASU 2016-05, "Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships." ASU 2016-05 clarifies that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument does not, in and of itself, require re-designation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The Company adopted this guidance on January 1, 2017. The adoption of ASU 2016-05 did not have a material impact on the Company's consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This ASU is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company adopted this guidance prospectively on January 1, 2017, and prior periods have not been adjusted. As a result of the adoption of this guidance, the Company no longer presents the tax effects from vesting of restricted stock grants and stock option exercises on its condensed consolidated statement of noncontrolling interests and equity. In August 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 provides guidance on several specific cash flow issues, including the classification of debt prepayment or debt extinguishment costs, contingent consideration payments, and distributions received from equity method investees. This guidance is effective for fiscal years beginning after December 15, 2017. The Company is currently evaluating the new guidance to determine the impact it may have on its consolidated financial statements. In October 2016, the FASB issued ASU 2016-18, "Statement of Cash Flows (Topic 230)," which requires that a statement of cash flows explains the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on its consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805): Clarifying the Definition of a Business," which provides guidance on whether transactions should be accounted for as acquisitions or disposals of assets or businesses. Specifically, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar identifiable assets, the set of assets is not a business. Additionally, ASU 2017-01 also provides other guidance providing a more robust framework to use in determining whether a set of assets and activities is a business. This guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted for transactions for which the acquisition or disposition date occurs before the issuance date or effective date of the amendments, only when the transaction has not been reported in financial statements that have been issued. The Company adopted ASU 2017-01 for new acquisitions beginning on January 1, 2017. The costs related to the acquisitions of stores that qualify as asset acquisitions will be capitalized as part of the purchase.

BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements of the Company are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information, and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they may not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2017, are not necessarily indicative of results that may be expected for the year ending December 31, 2017. The condensed consolidated balance sheet as of December 31, 2016 has been derived from the Company’s audited financial statements as of that date, but does not include all of the information and footnotes required by GAAP for complete financial statements. For further information refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission.

Recently Issued Accounting Standards

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers,” which amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. ASU 2014-09 outlines a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. The new standard will become effective for annual and interim periods beginning after December 15, 2017 with early adoption permitted. The Company has determined that its property rental revenue and tenant reinsurance revenue will not be subject to the guidance in ASU 2014-09, as they qualify as lease contracts and insurance contracts, which are excluded from its scope. The Company's management fee revenue will be included in the scope of the standard. However, based on the Company's initial assessment, it appears that revenue recognized under the standard will not differ materially from revenue recognized under existing guidance. The Company continues to assess the potential impacts of ASU 2014-09. The Company anticipates adopting the standard using the modified retrospective transition method as of January 1, 2018.

In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which modifies the accounting for leases, intending to increase transparency and comparability of organizations by requiring balance sheet presentation of leased assets and increased financial statement disclosure of leasing arrangements. ASU 2016-02 will require entities to recognize a liability for their lease obligations and a corresponding asset representing the right to use the underlying asset over the lease term. Lease obligations are to be measured at their present value and accounted for using the effective interest method. The accounting for the leased asset will differ slightly depending on whether the agreement is deemed to be a financing or operating lease. For financing leases, the leased asset is depreciated on a straight-line basis and depreciation expense is recorded separately from the interest expense in the statements of operations, resulting in higher expense in the earlier part of the lease term. For operating leases, the depreciation and interest expense components are combined, recognized evenly over the term of the lease, and presented as a reduction to operating income. ASU 2016-02 requires that assets and liabilities be presented or disclosed separately, and requires additional disclosure of certain qualitative and quantitative information related to these lease agreements. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018. The Company is currently assessing the impact of the adoption of ASU 2016-02 on the Company’s consolidated financial statements.

In March 2016, the FASB issued ASU 2016-05, "Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships." ASU 2016-05 clarifies that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument does not, in and of itself, require re-designation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The Company adopted this guidance on January 1, 2017. The adoption of ASU 2016-05 did not have a material impact on the Company's consolidated financial statements.

In March 2016, the FASB issued ASU 2016-09, “Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This ASU is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company adopted this guidance prospectively on January 1, 2017, and prior periods have not been adjusted. As a result of the adoption of this guidance, the Company no longer presents the tax effects from vesting of restricted stock grants and stock option exercises on its condensed consolidated statement of noncontrolling interests and equity.

In August 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 provides guidance on several specific cash flow issues, including the classification of debt prepayment or debt extinguishment costs, contingent consideration payments, and distributions received from equity method investees. This guidance is effective for fiscal years beginning after December 15, 2017. The Company is currently evaluating the new guidance to determine the impact it may have on its consolidated financial statements.

In October 2016, the FASB issued ASU 2016-18, "Statement of Cash Flows (Topic 230)," which requires that a statement of cash flows explains the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on its consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805): Clarifying the Definition of a Business," which provides guidance on whether transactions should be accounted for as acquisitions or disposals of assets or businesses. Specifically, when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar identifiable assets, the set of assets is not a business. Additionally, ASU 2017-01 also provides other guidance providing a more robust framework to use in determining whether a set of assets and activities is a business. This guidance is effective for annual periods beginning after December 15, 2017. Early adoption is permitted for transactions for which the acquisition or disposition date occurs before the issuance date or effective date of the amendments, only when the transaction has not been reported in financial statements that have been issued. The Company adopted ASU 2017-01 for new acquisitions beginning on January 1, 2017. The costs related to the acquisitions of stores that qualify as asset acquisitions will be capitalized as part of the purchase.