Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The unaudited consolidated financial statements included herein have been prepared pursuant to accounting principles generally accepted in the United States of America and should be read in conjunction with the consolidated financial statements and notes thereto of the Company’s and the Operating Partnership’s combined Annual Report on Form 10-K for the year ended December 31, 2019. The December 31, 2019 balance sheet data in this Form 10-Q was derived from audited financial statements. Certain information and note disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the SEC’s rules and regulations, although management believes that the disclosures are adequate to make the information presented not misleading. In the opinion of management, all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation of the financial statements for the interim periods have been made. The results of interim periods are not necessarily indicative of the results for a full year. The Company currently consolidates the Operating Partnership because it has (1) the power to direct the activities of the Operating Partnership that most significantly impact the Operating Partnership’s economic performance and (2) the obligation to absorb losses and the right to receive the residual returns of the Operating Partnership that could be potentially significant. We consolidate properties that are wholly-owned and properties where we own less than 100% but control such properties. Control is determined using an evaluation based on accounting standards related to the consolidation of voting interest entities and variable interest entities (“VIE”). For joint ventures that are determined to be a VIE, we consolidate the entity where we are deemed to be the primary beneficiary. Determination of the primary beneficiary is based on whether an entity has (1) the power to direct the activities of the VIE that most significantly impact the entity’s economic performance, and (2) the obligation to absorb losses of the entity that could potentially be significant to the VIE or the right to receive benefits from the entity that could potentially be significant to the VIE. Our determination of the primary beneficiary considers all relationships between us and the VIE, including management agreements and other contractual arrangements. Investments in real estate joint ventures that we do not control but may exercise significant influence on are accounted for using the equity method of accounting. These investments are recorded initially at cost and subsequently adjusted for our equity in the joint venture’s net income or loss, cash contributions, distributions and other adjustments required under the equity method of accounting. For certain investments in real estate joint ventures, we record our equity in the venture’s net income or loss under the hypothetical liquidation at book value (“HLBV”) method of accounting due to the structures and the preferences we receive on the distributions from our joint ventures pursuant to the respective joint venture agreements for those joint ventures. Under this method, we recognize income and loss in each period based on the change in liquidation proceeds we would receive from a hypothetical liquidation of our investment based on depreciated book value. Therefore, income or loss may be allocated disproportionately as compared to the ownership percentages due to specified preferred return rate thresholds and may be more or less than actual cash distributions received and more or less than what we may receive in the event of an actual liquidation. We separately report investments in joint ventures for which accumulated distributions have exceeded investments in, and our share of net income or loss of, the joint ventures within other liabilities in the consolidated balance sheets because we are committed to provide further financial support to these joint ventures. The carrying amount of our investments in the Charlotte, Columbus, Galveston/Houston, and National Harbor joint ventures are less than zero because of financing or operating distributions that were greater than net income, as net income includes non-cash charges for depreciation and amortization. “Noncontrolling interests in the Operating Partnership” reflects the Non-Company LP’s percentage ownership of the Operating Partnership’s units. “Noncontrolling interests in other consolidated partnerships” consist of outside equity interests in partnerships or joint ventures not wholly-owned by the Company or the Operating Partnership that are consolidated with the financial results of the Company and Operating Partnership because the Operating Partnership exercises control over the entities that own the properties. Noncontrolling interests are initially recorded in the consolidated balance sheets at fair value based upon purchase price allocations. Income is allocated to the noncontrolling interests based on the allocation provisions within the partnership or joint venture agreements. Impairment of Long-Lived Assets Rental property held and used by us is reviewed for impairment in the event that facts and circumstances indicate that the carrying amount of an asset may not be recoverable. In such an event, we compare the estimated future undiscounted cash flows associated with the asset to the asset's carrying amount, and if less, recognize an impairment loss in an amount by which the carrying amount exceeds its fair value. During the first quarter of 2020, we determined that the estimated future undiscounted cash flows of our Foxwoods outlet center, Mashantucket, Connecticut did not exceed the property's carrying value due to a decline in forecasted operating results. Therefore, we recorded a $45.7 million non-cash impairment charge in our consolidated statement of operations which equaled the excess of the property's carrying value over its estimated fair value. If the effects of the COVID-19 pandemic cause economic and market conditions to continue to deteriorate or if our expected holding periods for assets change, subsequent tests for impairment could result in additional impairment charges in the future. We can provide no assurance that material impairment charges with respect to our investment properties will not occur during the remaining quarters in 2020 or future periods.