Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies There have been no material changes to the summary of significant accounting policies included in the section entitled "Summary of Significant Accounting Policies" in our December 31, 2017 Annual Report on Form 10-K. Basis of Quarterly Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), for interim financial information, and with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments and eliminations (including intercompany balances and transactions), consisting of normal recurring adjustments, considered necessary for the fair presentation of the financial statements have been included. The results of operations for the periods presented are not necessarily indicative of the results that may be expected for the corresponding full years. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the financial statements for the year ended December 31, 2017 contained in our Annual Report on Form 10-K. We do not consider our business to be subject to material seasonal fluctuations, except that our observatory business is subject to tourism seasonality. During the past ten years, approximately 16.0% to 18.0% of our annual observatory revenue was realized in the first quarter, 26.0% to 28.0% was realized in the second quarter, 31.0% to 33.0% was realized in the third quarter and 23.0% to 25.0% was realized in the fourth quarter. We consolidate entities in which we have a controlling financial interest. In determining whether we have a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, we consider factors such as ownership interest, board representation, management representation, authority to make decisions, and contractual and substantive participating rights of the partners/members. For variable interest entities ("VIE"), we consolidate the entity if we are deemed to have a variable interest in the entity and through that interest we are deemed the primary beneficiary. The primary beneficiary of a VIE is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. The primary beneficiary is required to consolidate the VIE. The Operating Partnership is a variable interest entity of our company, Empire State Realty Trust, Inc. As the Operating Partnership is already consolidated in the financial statements of Empire State Realty Trust, Inc., the identification of this entity as a variable interest entity has no impact on our consolidated financial statements. We will assess the accounting treatment for each investment we may have in the future. This assessment will include a review of each entity’s organizational agreement to determine which party has what rights and whether those rights are protective or participating. For all VIEs, we will review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity’s economic performance and benefit. In situations where we or our partner could approve, among other things, the annual budget, or leases that cover more than a nominal amount of space relative to the total rentable space at each property, we would not consolidate the investment as we consider these to be substantive participation rights that result in shared power of the activities that would most significantly impact the performance and benefit of such joint venture investment. A non-controlling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to a parent. Non-controlling interests are required to be presented as a separate component of equity in the condensed consolidated balance sheets and in the condensed consolidated statements of income by requiring earnings and other comprehensive income to be attributed to controlling and non-controlling interests. Accounting Estimates The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to use estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Significant items subject to such estimates and assumptions include allocation of the purchase price of acquired real estate properties among tangible and intangible assets, determination of the useful life of real estate properties and other long-lived assets, valuation and impairment analysis of commercial real estate properties and other long-lived assets, estimate of tenant expense reimbursements, valuation of the allowance for doubtful accounts, and valuation of derivative instruments, senior unsecured notes, mortgage notes payable, unsecured term loan and revolving credit facilities, and equity based compensation. These estimates are prepared using management’s best judgment, after considering past, current, and expected events and economic conditions. Actual results could differ from those estimates. Reclassification Certain prior year balances have been reclassified to conform to our current year presentation. The prior year balances of other revenues and interest expense have been reclassified to separately present lease termination fees and loss on early extinguishment of debt, respectively. Recently Issued or Adopted Accounting Standards During January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which contain amendments that modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. An entity no longer will determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. Because these amendments eliminate Step 2 from the goodwill impairment test, they should reduce the cost and complexity of evaluating goodwill for impairment. ASU No. 2017-04 should be applied on a prospective basis and the amendments adopted for the annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We are evaluating the impact of adopting this new accounting standard on our consolidated financial statements. During January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which contain amendments 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. The amendments in ASU No. 2017-01 provide a screen to determine when an integrated set of assets and activities (collectively referred to as 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. This screen reduces the number of transactions that need to be further evaluated. Real estate acquisitions that do not meet the definition of a business will be accounted for as asset acquisitions and the corresponding acquisition costs will be capitalized rather than expensed. These amendments narrow the definition of the term output so that the term is consistent with how outputs are described in Topic 606, Revenue from Contracts with Customers. ASU No. 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments are applied prospectively on or after the effective date. No disclosures are required at transition. We believe that acquisitions of real estate properties will generally be considered asset acquisitions. During November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which contain amendments that require 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 No. 2016-18 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We adopted this standard on January 1, 2018 using a retrospective transition method. The adoption did not have a material impact on our consolidated financial statements. During August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU No. 2016-15 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this standard on January 1, 2018 using a retrospective transition method. The adoption did not have a material impact on our consolidated financial statements. During June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which contains amendments that replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU No. 2016-13 will be effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Earlier adoption as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, is permitted. The amendments must 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 (that is, a modified retrospective approach). We are evaluating the impact of adopting this new accounting standard on our consolidated financial statements. During February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. ASU No. 2016-02 leaves the accounting for leases by lessors largely unchanged from previous GAAP. ASU No. 2016-02 will be effective for fiscal years beginning after December 15, 2018 and subsequent interim periods. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Transition will require application of the new guidance at the beginning of the earliest comparative period presented. This ASU is expected to result in the recognition of a right-to-use asset and related liability to account for our future obligations under our ground lease agreements for which we are the lessee. As of March 31, 2018, the remaining contractual payments under our ground lease agreements aggregated $60.9 million. In addition, under ASU 2016-02, lessors may only capitalize incremental direct leasing costs. As a result, we expect that we will no longer capitalize our internal leasing costs and instead will expense these costs as incurred. These costs totaled $2.6 million for the year ended December 31, 2017. We continue to evaluate the impact of adopting this new accounting standard on our consolidated financial statements. During May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which replaces all current GAAP guidance related to revenue recognition and eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We adopted this standard on January 1, 2018 and it did not have a material impact on our consolidated financial statements.

Summary of Significant Accounting Policies

There have been no material changes to the summary of significant accounting policies included in the section entitled "Summary of Significant Accounting Policies" in our December 31, 2017 Annual Report on Form 10-K.

Basis of Quarterly Presentation and Principles of Consolidation

The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), for interim financial information, and with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments and eliminations (including intercompany balances and transactions), consisting of normal recurring adjustments, considered necessary for the fair presentation of the financial statements have been included.

The results of operations for the periods presented are not necessarily indicative of the results that may be expected for the corresponding full years. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the financial statements for the year ended December 31, 2017 contained in our Annual Report on Form 10-K. We do not consider our business to be subject to material seasonal fluctuations, except that our observatory business is subject to tourism seasonality. During the past ten years, approximately 16.0% to 18.0% of our annual observatory revenue was realized in the first quarter, 26.0% to 28.0% was realized in the second quarter, 31.0% to 33.0% was realized in the third quarter and 23.0% to 25.0% was realized in the fourth quarter.

We consolidate entities in which we have a controlling financial interest. In determining whether we have a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, we consider factors such as ownership interest, board representation, management representation, authority to make decisions, and contractual and substantive participating rights of the partners/members. For variable interest entities ("VIE"), we consolidate the entity if we are deemed to have a variable interest in the entity and through that interest we are deemed the primary beneficiary. The primary beneficiary of a VIE is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. The primary beneficiary is required to consolidate the VIE. The Operating Partnership is a variable interest entity of our company, Empire State Realty Trust, Inc. As the Operating Partnership is already consolidated in the financial statements of Empire State Realty Trust, Inc., the identification of this entity as a variable interest entity has no impact on our consolidated financial statements.

We will assess the accounting treatment for each investment we may have in the future. This assessment will include a review of each entity’s organizational agreement to determine which party has what rights and whether those rights are protective or participating. For all VIEs, we will review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity’s economic performance and benefit. In situations where we or our partner could approve, among other things, the annual budget, or leases that cover more than a nominal amount of space relative to the total rentable space at each property, we would not consolidate the investment as we consider these to be substantive participation rights that result in shared power of the activities that would most significantly impact the performance and benefit of such joint venture investment.

A non-controlling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to a parent. Non-controlling interests are required to be presented as a separate component of equity in the condensed consolidated balance sheets and in the condensed consolidated statements of income by requiring earnings and other comprehensive income to be attributed to controlling and non-controlling interests.

Accounting Estimates

The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to use estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Significant items subject to such estimates and assumptions include allocation of the purchase price of acquired real estate properties among tangible and intangible assets, determination of the useful life of real estate properties and other long-lived assets, valuation and impairment analysis of commercial real estate properties and other long-lived assets, estimate of tenant expense reimbursements, valuation of the allowance for doubtful accounts, and valuation of derivative instruments, senior unsecured notes, mortgage notes payable, unsecured term loan and revolving credit facilities, and equity based compensation. These estimates are prepared using management’s best judgment, after considering past, current, and expected events and economic conditions. Actual results could differ from those estimates.

Reclassification

Certain prior year balances have been reclassified to conform to our current year presentation. The prior year balances of other revenues and interest expense have been reclassified to separately present lease termination fees and loss on early extinguishment of debt, respectively.

Recently Issued or Adopted Accounting Standards

During January 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which contain amendments that modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. An entity no longer will determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. Because these amendments eliminate Step 2 from the goodwill impairment test, they should reduce the cost and complexity of evaluating goodwill for impairment. ASU No. 2017-04 should be applied on a prospective basis and the amendments adopted for the annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We are evaluating the impact of adopting this new accounting standard on our consolidated financial statements.

During January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business, which contain amendments 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. The amendments in ASU No. 2017-01 provide a screen to determine when an integrated set of assets and activities (collectively referred to as 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. This screen reduces the number of transactions that need to be further evaluated. Real estate acquisitions that do not meet the definition of a business will be accounted for as asset acquisitions and the corresponding acquisition costs will be capitalized rather than expensed. These amendments narrow the definition of the term output so that the term is consistent with how outputs are described in Topic 606, Revenue from Contracts with Customers. ASU No. 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments are applied prospectively on or after the effective date. No disclosures are required at transition. We believe that acquisitions of real estate properties will generally be considered asset acquisitions.

During November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which contain amendments that require 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 No. 2016-18 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. We adopted this standard on January 1, 2018 using a retrospective transition method. The adoption did not have a material impact on our consolidated financial statements.

During August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, which addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU No. 2016-15 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this standard on January 1, 2018 using a retrospective transition method. The adoption did not have a material impact on our consolidated financial statements.

During June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which contains amendments that replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU No. 2016-13 will be effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Earlier adoption as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, is permitted. The amendments must 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 (that is, a modified retrospective approach). We are evaluating the impact of adopting this new accounting standard on our consolidated financial statements.

During February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. ASU No. 2016-02 leaves the accounting for leases by lessors largely unchanged from previous GAAP. ASU No. 2016-02 will be effective for fiscal years beginning after December 15, 2018 and subsequent interim periods. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Transition will require application of the new guidance at the beginning of the earliest comparative period presented. This ASU is expected to result in the recognition of a right-to-use asset and related liability to account for our future obligations under our ground lease agreements for which we are the lessee. As of March 31, 2018, the remaining contractual payments under our ground lease agreements aggregated $60.9 million. In addition, under ASU 2016-02, lessors may only capitalize incremental direct leasing costs. As a result, we expect that we will no longer capitalize our internal leasing costs and instead will expense these costs as incurred. These costs totaled $2.6 million for the year ended December 31, 2017. We continue to evaluate the impact of adopting this new accounting standard on our consolidated financial statements.

During May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which replaces all current GAAP guidance related to revenue recognition and eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We adopted this standard on January 1, 2018 and it did not have a material impact on our consolidated financial statements.