Description of Business and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Our Consolidated Financial Statements are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The Company's Consolidated Financial Statements include the Operating Partnership, wholly owned subsidiaries and those entities in which the Company has the controlling interest. The Operating Partnership's Consolidated Financial Statements include wholly owned subsidiaries and those entities in which the Operating Partnership has the controlling interest. All intercompany transactions and accounts have been eliminated. The unaudited interim consolidated financial statements and accompanying unaudited consolidated financial information, in the opinion of management, contain all adjustments (including normal recurring accruals) necessary for a fair presentation of our financial position, results of operations and cash flows. We have condensed or omitted certain notes and other information from the interim Consolidated Financial Statements presented in this Quarterly Report as permitted by SEC rules and regulations. These Consolidated Financial Statements should be read in conjunction with our 2016 Annual Report on Form 10-K.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires us to make estimates and assumptions that affect the amounts reported in our Consolidated Financial Statements and accompanying notes. Actual results could differ from those estimates.
Recently Issued Accounting Standards	Recently Issued Accounting Standards The Financial Accounting Standards Board ("FASB") issued an accounting standards update ("ASU") that requires the use of a new five-step model to recognize revenue from customer contracts. The five-step model requires that we identify the contract with the customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract and recognize revenue when we satisfy the performance obligations. We will also be required to disclose information regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Upon adoption of the ASU in 2018, we expect to utilize the modified retrospective approach. We are currently conducting our analysis of the impact of the guidance on our Consolidated Financial Statements, including our internal control processes, and have an active project team working on the evaluation and implementation of the guidance. Our analysis of our non-lease related revenue contracts, which include primarily real estate sales, management, development and construction fee income and transient parking income, indicates that the adoption of this ASU will impact the financial statement disclosure of these contracts with no material impact on the timing of revenue recognition; however, we continue to evaluate the impacts of adoption of this ASU. We expect additional impact of this ASU upon adoption of the ASU related to accounting for leases discussed below for certain lease revenue streams that will be required to be evaluated as non-lease components using the five-step revenue recognition model. The FASB issued an ASU that adds to and clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. The ASU is required to be adopted in 2018 with retrospective application required. We do not expect such adoption to have a material effect on our Consolidated Statements of Cash Flows. The FASB issued an ASU that clarifies and narrows the definition of a business used in determining whether to account for a transaction as an asset acquisition or business combination. The guidance requires evaluation of the fair value of the assets acquired to determine if it is concentrated in a single identifiable asset or a group of similar identifiable assets. If so, the transferred assets would not be a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs. The ASU is required to be adopted in 2018 and applied prospectively. Upon adoption of this ASU, we expect that the majority of our future acquisitions would not meet the definition of a business; therefore, the related acquisition costs would be capitalized as part of the purchase price. The FASB issued an ASU that clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. The guidance requires modification accounting if the value, vesting conditions or classification of the award changes. The ASU is required to be adopted in 2018 and applied prospectively. We do not expect such adoption to have a material effect on our Consolidated Financial Statements. The FASB issued an ASU which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both lessees and lessors. We are currently conducting our initial analysis of the impact of the guidance on our Consolidated Financial Statements and have an active project team working on the evaluation and implementation of the guidance. We currently believe that the adoption of the ASU will not significantly change the accounting for operating leases on our Consolidated Balance Sheets where we are the lessor, and that such leases will be accounted for in a similar method to existing standards with the underlying leased asset being reported and recognized as a real estate asset. In addition, the guidance requires lessors to capitalize and amortize only incremental direct leasing costs. As a result, we expect that upon the adoption of the ASU, we will no longer be able to capitalize and amortize certain leasing related costs and instead will expense these costs as incurred. We are in the process of evaluating the impact to our results of operations of expensing such costs. The ASU is required to be adopted in 2019 using a modified retrospective approach. Our initial analysis of our leases also indicates that upon adoption of the ASU, certain lease revenue streams that are currently accounted for using the lease accounting standard will be accounted for as non-lease components using the five-step revenue recognition model discussed above. We continue to evaluate other impacts of adoption of this ASU. The FASB issued an ASU that eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item when the hedged item affects earnings. The ASU is required to be adopted in 2019 using a modified retrospective approach. We do not expect such adoption to have a material effect on our Consolidated Financial Statements. 1. Description of Business and Significant Accounting Policies – Continued The FASB issued an ASU that requires, among other things, the use of a new current expected credit loss ("CECL") model in determining our allowances for doubtful accounts with respect to accounts receivable, accrued straight-line rents receivable and mortgages and notes receivable. The CECL model requires that we estimate our lifetime expected credit loss with respect to these receivables and record allowances that, when deducted from the balance of the receivables, represent the net amounts expected to be collected. We will also be required to disclose information about how we developed the allowances, including changes in the factors (e.g., portfolio mix, credit trends, unemployment, gross domestic product, etc.) that influenced our estimate of expected credit losses and the reasons for those changes. We will apply the ASU’s provisions as a cumulative-effect adjustment to retained earnings upon adoption in 2020. We are in the process of evaluating this ASU.