Significant Accounting Policies	6 Months Ended
Significant Accounting Policies	Jun. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). The condensed consolidated financial statements include the financial position and results of operations of the Company and its consolidated subsidiaries, including the Operating Partnership, its wholly-owned subsidiaries, and any interests in variable interest entities ("VIEs") where the Company has been determined to be the primary beneficiary. All significant intercompany transactions and balances have been eliminated in consolidation. In the opinion of management, the condensed consolidated financial statements reflect all adjustments, consisting of normal recurring accruals, which are necessary for the fair presentation of the financial condition and results of operations for the interim periods presented. The accompanying condensed consolidated financial statements were prepared in accordance with the requirements for interim financial information. Accordingly, these interim financial statements have not been audited and exclude certain disclosures required for annual financial statements. Also, the operating results presented for interim periods are not necessarily indicative of the results that may be expected for any other interim period or for the entire year. These interim financial statements should be read in conjunction with the audited consolidated financial statements of the Company included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed. Such estimates are based on management’s historical experience and best judgment after considering past, current, and expected events and economic conditions. Actual results could differ significantly from management’s estimates. Recent Accounting Pronouncements Leases On February 25, 2016, the Financial Accounting Standards Board ("FASB") issued an Accounting Standards Update ("ASU") that requires lessees to recognize most leases on their balance sheets as lease liabilities with corresponding right-of-use assets (ASU 2016-02—Leases (Topic 842)). The new standard also makes targeted changes to lessor accounting. The Company adopted the new standard on January 1, 2019, using the modified retrospective approach for all leases existing at, or entered into after, the beginning of the earliest comparative period presented as permitted in Accounting Standards Codification ("ASC") Topic 842. In addition, the Company elected the package of practical expedients permitted under the transition guidance within the new standard, which allowed the Company to not reassess whether any expired or existing contracts are or contain leases, not reassess the lease classification for any expired or existing leases, and not reassess initial direct costs for existing leases. As of January 1, 2019, Company did not have any leases classified as finance leases. The Company also elected a practical expedient that allowed it to not separate non-lease components from lease components and instead to account for each lease and non-lease component as a single lease component. The adoption of the new standard as of January 1, 2019 did not impact the Company's consolidated results of operations and had no impact on cash flows. As a lessee, the Company had six ground leases on five properties as of January 1, 2019 with initial terms that range from 20 to 65 years and options to extend up to an additional 70 years in certain cases. The exercise of lease renewal options is at the Company's sole discretion. The depreciable life of assets and leasehold improvements are limited by the expected lease term. The Company recognizes lease expense for operating leases on a straight-line basis over the lease term. The Company's lease agreements do not contain any residual value guarantees or material restrictive covenants. The long-term ground leases represent a majority of the Company's current operating lease payments. The Company recorded right-of-use assets totaling $32.2 million and lease liabilities totaling $41.4 million upon adopting this standard on January 1, 2019. The Company utilized a weighted average discount rate of 5.4% to measure its lease liabilities upon adoption. As a lessor, the Company leases its properties under operating leases and recognizes base rents on a straight-line basis over the lease term. The Company also recognizes revenue from tenant recoveries, through which tenants reimburse the Company on an accrual basis for certain expenses such as utilities, janitorial services, repairs and maintenance, security and alarms, parking lot and ground maintenance, administrative services, management fees, insurance, and real estate taxes. Rental revenues are reduced by the amount of any leasing incentives amortized on a straight-line basis over the term of the applicable lease. In addition, the Company recognizes contingent rental revenue (e.g., percentage rents based on tenant sales thresholds) when the sales thresholds are met. Many tenant leases include one or more options to renew, with renewal terms that can extend the lease term from one to 15 years or more. The exercise of lease renewal options is at the tenant's sole discretion. The Company includes a renewal period in the lease term only if it appears at lease inception that the renewal is reasonably assured. The new standard includes new considerations regarding the recognition of rental revenue when collection is not probable. The Company changed its presentation and measurement of charges for uncollectable lease revenue associated with its office, retail, and residential leasing activity, reflecting those amounts as a component of rental income on the accompanying Condensed Consolidated Statement of Comprehensive Income for the three and six months ended June 30, 2019. However, in accordance with its prospective adoption of the standard, the Company did not adjust the prior year period presentation of charges for uncollectable lease revenue associated with its office, retail, and residential leasing activity as a component of operating expenses, excluding property taxes, on the accompanying Condensed Consolidated Statement of Comprehensive Income for the three and six months ended June 30, 2018. Instead, the Company recorded a combined adjustment of $0.2 million to the opening balances for distributions in excess of earnings and noncontrolling interest relating to receivables where collection of substantially all operating lease payments was not probable as of January 1, 2019. Lease-related receivables, which include contractual amounts accrued and unpaid from tenants and accrued straight-line rents receivable, are reduced for credit losses. Such amounts are recognized as a reduction to real estate rental revenues. The Company evaluates the collectability of lease receivables using several factors, including a lessee’s creditworthiness. The Company recognizes a credit loss on lease-related receivables when, in the opinion of management, collection of substantially all lease payments is not probable. When collectability is determined not probable, any lease income subsequent to recognizing the credit loss is limited to the lesser of the lease income reflected on a straight-line basis or cash collected. Credit losses In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses - Measurement of Credit Losses on Financial Instruments (Topic 326). ASU 2016-13 significantly changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The guidance will replace the "incurred loss" approach under existing guidance with an "expected loss" model for instruments measured at amortized cost, such as our notes receivable. The guidance is effective for fiscal years beginning after December 15, 2019 and is to be adopted through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. While the Company is currently evaluating the impact ASU 2016-13 will have on the consolidated financial statements, the Company expects that the adoption could result in earlier recognition of a provision for loan losses on its notes receivable. Other Accounting Policies See the Company's Annual Report on Form 10-K for the year ended December 31, 2018 for a description of other accounting principles upon which basis the accompanying consolidated financial statements were prepared.