Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Consolidation	Basis of Consolidation — Our consolidated financial statements reflect all of our accounts, including those of our controlled subsidiaries and our tenancy-in-common interest, as described below. The portions of equity in consolidated subsidiaries that are not attributable, directly or indirectly, to us are presented as noncontrolling interests. All significant intercompany accounts and transactions have been eliminated.
Reclassification	Reclassifications — Certain prior period amounts have been reclassified to conform to the current period presentation.
Recent Accounting Requirements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2014-09, Revenue from Contracts with Customers (Topic 606). ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services. ASU 2014-09 does not apply to our lease revenues, which constitute a majority of our revenues, but will primarily apply to revenues generated from our operating properties. We will adopt this guidance for our interim and annual periods beginning January 1, 2018 using one of two methods: retrospective restatement for each reporting period presented at the time of adoption, or retrospectively with the cumulative effect of initially applying this guidance recognized at the date of initial application. We have not decided which method of adoption we will use. We are evaluating the impact of the new standard and have not yet determined if it will have a material impact on our business or our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 outlines a new model for accounting by lessees, whereby their rights and obligations under substantially all leases, existing and new, would be capitalized and recorded on the balance sheet. For lessors, however, the accounting remains largely unchanged from the current model, with the distinction between operating and financing leases retained, but updated to align with certain changes to the lessee model and the new revenue recognition standard. The new standard also replaces existing sale-leaseback guidance with a new model applicable to both lessees and lessors. In addition, it also requires lessors to record gross revenues and expenses associated with activities that do not transfer services to the lessee (such as real estate taxes and insurance). Additionally, the new standard requires extensive quantitative and qualitative disclosures. The new standard must be adopted using a modified retrospective transition of the new guidance and provides for certain practical expedients. Transition will require application of the new model at the beginning of the earliest comparative period presented. We will adopt this guidance for our interim and annual periods beginning January 1, 2019. Early application will be permitted for all entities. The ASU is expected to impact our consolidated financial statements as we have land lease arrangements for which we are the lessee. We are evaluating the impact of the new standard and have not yet determined if it will have a material impact on our business or our consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments — Credit Losses. ASU 2016-13 introduces a new model for estimating credit losses based on current expected credit losses for certain types of financial instruments, including loans receivable, held-to-maturity debt securities, and net investments in direct financing leases, amongst other financial instruments. ASU 2016-13 also modifies the impairment model for available-for-sale debt securities and expands the disclosure requirements regarding an entity’s assumptions, models, and methods for estimating the allowance for losses. ASU 2016-13 will be effective for public business entities in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, with early application of the guidance permitted. We are in the process of evaluating the impact of adopting ASU 2016-13 on our consolidated financial statements. 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 intends to reduce diversity in practice for certain cash flow classifications, including, but not limited to (i) debt prepayment or debt extinguishment costs, (ii) contingent consideration payments made after a business combination, (iii) proceeds from the settlement of insurance claims, and (iv) distributions received from equity method investees. ASU 2016-15 will be effective for public business entities in fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early application of the guidance permitted. We are in the process of evaluating the impact of adopting ASU 2016-15 on our consolidated financial statements and will retrospectively adopt the standard for the fiscal year beginning January 1, 2018. In October 2016, the FASB issued ASU 2016-17, Consolidation (Topic 810): Interests Held through Related Parties That Are under Common Control. ASU 2016-17 changes how a reporting entity that is a decision maker should consider indirect interests in a VIE held through an entity under common control. If a decision maker must evaluate whether it is the primary beneficiary of a VIE, it will only need to consider its proportionate indirect interest in the VIE held through a common control party. ASU 2016-17 amends ASU 2015-02, which we adopted on January 1, 2016, and which currently directs the decision maker to treat the common control party’s interest in the VIE as if the decision maker held the interest itself. ASU 2016-17 is effective for public business entities in fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. We adopted ASU 2016-17 as of January 1, 2017 on a prospective basis. The adoption of this standard did not have a material impact on our consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. ASU 2016-18 intends to reduce diversity in practice for the classification and presentation of changes in restricted cash on the statement of cash flows. ASU 2016-18 requires that a statement of cash flows explain 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. ASU 2016-18 will be effective for public business entities in fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early adoption permitted. We are in the process of evaluating the impact of adopting ASU 2016-18 on our consolidated financial statements and will retrospectively adopt the standard for the fiscal year beginning January 1, 2018. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. ASU 2017-01 intends to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. Under the current implementation guidance in Topic 805, there are three elements of a business: inputs, processes, and outputs. While an integrated set of assets and activities, collectively referred to as a “set,” that is a business usually has outputs, outputs are not required to be present. ASU 2017-01 provides a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. ASU 2017-01 will be effective for public business entities in fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early adoption permitted. We elected to early adopt ASU 2017-01 on January 1, 2017 on a prospective basis. While our acquisitions have historically been classified as either business combinations or asset acquisitions, certain acquisitions that were classified as business combinations by us likely would have been considered asset acquisitions under the new standard. As a result, transaction costs are more likely to be capitalized since we expect most of our future acquisitions to be classified as asset acquisitions under this new standard. In addition, goodwill that was previously allocated to businesses that were sold or held for sale will no longer be allocated and written off upon sale if future sales were deemed to be sales of assets and not businesses. In January 2017, the FASB issued ASU 2017-04, Intangibles — Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. ASU 2017-04 removes step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. All other goodwill impairment guidance will remain largely unchanged. Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. ASU 2017-04 will be effective for public business entities in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years in which a goodwill impairment test is performed, with early adoption permitted. We adopted ASU 2017-04 as of April 1, 2017 on a prospective basis. The adoption of this standard did not have a material impact on our consolidated financial statements. In February 2017, the FASB issued ASU 2017-05, Other Income — Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20). ASU 2017-05 clarifies that a financial asset is within the scope of Subtopic 610-20 if it meets the definition of an in substance nonfinancial asset. The amendments define the term “in substance nonfinancial asset,” in part, as a financial asset promised to a counterparty in a contract if substantially all of the fair value of the assets (recognized and unrecognized) that are promised to the counterparty in the contract is concentrated in nonfinancial assets. If substantially all of the fair value of the assets that are promised to the counterparty in a contract is concentrated in nonfinancial assets, then all of the financial assets promised to the counterparty are in substance nonfinancial assets within the scope of Subtopic 610-20. This amendment also clarifies that nonfinancial assets within the scope of Subtopic 610-20 may include nonfinancial assets transferred within a legal entity to a counterparty. For example, a parent company may transfer control of nonfinancial assets by transferring ownership interests in a consolidated subsidiary. ASU 2017-05 is effective for periods beginning after December 15, 2017, with early application permitted for fiscal years beginning after December 15, 2016. We are in the process of evaluating the impact of ASU 2017-05 on our consolidated financial statements and will adopt the standard for the fiscal year beginning January 1, 2018. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. ASU 2017-12 will make more financial and nonfinancial hedging strategies eligible for hedge accounting. It also amends the presentation and disclosure requirements and changes how companies assess hedge effectiveness. It is intended to more closely align hedge accounting with companies’ risk management strategies, simplify the application of hedge accounting, and increase transparency as to the scope and results of hedging programs. ASU 2017-12 will be effective in fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. We are in the process of evaluating the impact of adopting ASU 2017-12 on our consolidated financial statements and will adopt the standard for the fiscal year beginning January 1, 2018.
Equity Method Investments	We own equity interests in net-leased properties that are generally leased to companies through noncontrolling interests (i) in partnerships and limited liability companies that we do not control but over which we exercise significant influence or (ii) as tenants-in-common subject to common control. Generally, the underlying investments are jointly owned with affiliates. We account for these investments under the equity method of accounting. Earnings for each investment are recognized in accordance with each respective investment agreement and, where applicable, based upon an allocation of the investment’s net assets at book value as if the investment were hypothetically liquidated at the end of each reporting period. As required by current authoritative accounting guidance, we periodically compare an investment’s carrying value to its estimated fair value and recognize an impairment charge to the extent that the carrying value exceeds fair value and such decline is determined to be other than temporary. Additionally, we provide funding to developers for ADC Arrangements, under which we have provided loans to third-party developers of real estate projects, which we account for as equity investments as the characteristics of the arrangement with the third-party developers are more similar to a jointly owned investment or partnership rather than a loan.
Intangible Assets and Liabilities	Amortization of below-market rent and above-market rent intangibles is recorded as an adjustment to Rental income; amortization of below-market ground lease and above-market ground lease intangibles is included in Property expenses; and amortization of in-place lease intangibles is included in Depreciation and amortization.
Fair Value of Financial Instruments	Derivative Assets — Our derivative assets, which are included in Other assets, net in the consolidated financial statements, are comprised of interest rate caps, interest rate swaps, foreign currency forward contracts, stock warrants, and foreign currency collars (Note 9). The interest rate caps, interest rate swaps, foreign currency forward contracts, and foreign currency collars were measured at fair value using readily observable market inputs, such as quotations on interest rates, and were classified as Level 2 as these instruments are custom, over-the-counter contracts with various bank counterparties that are not traded in an active market. The stock warrants were measured at fair value using internal valuation models that incorporated market inputs and our own assumptions about future cash flows. We classified these assets as Level 3 because they are not traded in an active market. Derivative Liabilities — Our derivative liabilities, which are included in Accounts payable, accrued expenses and other liabilities in the consolidated financial statements, are comprised of interest rate swaps and foreign currency collars (Note 9). These derivative instruments were measured at fair value using readily observable market inputs, such as quotations on interest rates, and were classified as Level 2 because they are custom, over-the-counter contracts with various bank counterparties that are not traded in an active market. The fair value of an asset is defined as the exit price, which is the amount that would either be received when an asset is sold or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The guidance establishes a three-tier fair value hierarchy based on the inputs used in measuring fair value. These tiers are: Level 1, for which quoted market prices for identical instruments are available in active markets, such as money market funds, equity securities, and U.S. Treasury securities; Level 2, for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument, such as certain derivative instruments including interest rate caps, interest rate swaps, foreign currency forward contracts, and foreign currency collars; and Level 3, for securities and other derivative assets that do not fall into Level 1 or Level 2 and for which little or no market data exists, therefore requiring us to develop our own assumptions.
Derivatives	We measure derivative instruments at fair value and record them as assets or liabilities, depending on our rights or obligations under the applicable derivative contract. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. For a derivative designated, and that qualified, as a cash flow hedge, the effective portion of the change in fair value of the derivative is recognized in Other comprehensive income until the hedged item is recognized in earnings. For a derivative designated, and that qualified, as a net investment hedge, the effective portion of the change in the fair value and/or the net settlement of the derivative is reported in Other comprehensive income as part of the cumulative foreign currency translation adjustment. For a derivative designated, and that qualified, as a net investment hedge, the effective portion of the change in the fair value and/or the net settlement of the derivative is reported in Other comprehensive income as part of the cumulative foreign currency translation adjustment. The ineffective portion of the change in fair value of any derivative is immediately recognized in earnings. All derivative transactions with an individual counterparty are governed by a master International Swap and Derivatives Association agreement, which can be considered as a master netting arrangement; however, we report all our derivative instruments on a gross basis on our consolidated financial statements.