Empire State Realty OP (FISK) 10-K 26 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36106
Entity Registrant Name	EMPIRE STATE REALTY OP, L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4685158
Entity Address, Address Line One	111 West 33rd Street
Entity Address, Address Line Two	12th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10120
City Area Code	212
Local Phone Number	687-8700
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Documents Incorporated by Reference	Our sole general partner is Empire State Realty Trust, Inc. Portions of the Empire State Realty Trust, Inc.'s Proxy Statement for its 2021 Annual Stockholders' Meeting (which is scheduled to be held on May 13, 2021 virtually via a live webcast) to be filed within 120 days after the end of Empire State Realty Trust, Inc.'s fiscal year are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001553079
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Public Float			$ 0
Series ES Operating Partnership Units Limited Partners
Document Information [Line Items]
Title of 12(b) Security	Series ES operating partnership units
Trading Symbol	ESBA
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		23,453,702
Series 60 Operating Partnership Units Limited Partners
Document Information [Line Items]
Title of 12(b) Security	Series 60 operating partnership units
Trading Symbol	OGCP
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		6,329,826
Series 250 Operating Partnership Units Limited Partners
Document Information [Line Items]
Title of 12(b) Security	Series 250 operating partnership units
Trading Symbol	FISK
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		3,171,531

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Commercial real estate properties, at cost:
Land	$ 201,196	$ 201,196
Development costs	7,966	7,989
Building and improvements	2,924,804	2,900,248
Commercial real estate properties, at cost, gross	3,133,966	3,109,433
Less: accumulated depreciation	(941,612)	(862,534)
Commercial real estate properties, net	2,192,354	2,246,899
Cash and cash equivalents	526,714	233,946
Restricted cash	41,225	37,651
Tenant and other receivables	21,541	25,423
Deferred rent receivables	222,508	220,960
Prepaid expenses and other assets	77,182	65,453
Deferred costs, net	203,853	228,150
Acquired below market ground leases, net	344,735	352,566
Right of use assets	29,104	29,307
Goodwill	491,479	491,479
Total assets	4,150,695	3,931,834
Liabilities:
Mortgage notes payable, net	775,929	605,542
Senior unsecured notes, net	973,159	798,392
Unsecured term loan facilities, net	387,561	264,640
Unsecured revolving credit facility	0	0
Accounts payable and accrued expenses	103,203	143,786
Acquired below market leases, net	31,705	39,679
Ground lease liabilities	29,104	29,307
Deferred revenue and other liabilities	88,319	72,015
Tenants’ security deposits	30,408	30,560
Total liabilities	2,419,388	1,983,921
Commitments and contingencies
Capital:
Total capital	1,731,307	1,947,913
Total liabilities and capital	4,150,695	3,931,834
Private Perpetual Preferred Units, Series 2019
Capital:
Series preferred units	21,936	21,147
Private Perpetual Preferred Units, Series 2014
Capital:
Series preferred units	8,004	8,004
Series PR Operating Partnership Units
Capital:
ESRT partners' capital (2,852,787 and 2,996,520 general partner operating partnership units and 168,712,617 and 178,897,876 limited partner operating partnership units outstanding at December 31, 2020 and 2019, respectively)	1,055,249	1,228,520
Limited partner operating partnership units	648,543	680,580
Series ES Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units	(1,348)	7,262
Series 60 Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units	(721)	1,593
Series 250 Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units	$ (356)	$ 807

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Capital:
General partner operating partnership units, outstanding (in shares)	171,600,000
Limited partner operating partnership units, outstanding (in shares)	113,700,000
Private Perpetual Preferred Units, Series 2019
Capital:
Private perpetual preferred units, liquidation preference per share (in dollars per share)	$ 13.52	$ 13.52
Private perpetual preferred units, issued (in shares)	4,664,038	4,610,383
Private perpetual preferred units, outstanding (in shares)	4,664,038	4,610,383
Private Perpetual Preferred Units, Series 2014
Capital:
Private perpetual preferred units, liquidation preference per share (in dollars per share)	$ 16.62	$ 16.62
Private perpetual preferred units, issued (in shares)	1,560,360	1,560,360
Private perpetual preferred units, outstanding (in shares)	1,560,360	1,560,360
Series PR Operating Partnership Units
Capital:
Limited partner operating partnership units, outstanding (in shares)	80,355,297	81,387,763
Series ES Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units, outstanding (in shares)	23,677,975	25,809,604
Series 60 Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units, outstanding (in shares)	6,424,567	7,025,089
Series 250 Operating Partnership Units Limited Partners
Capital:
Limited partner operating partnership units, outstanding (in shares)	3,255,480	3,535,197
ESRT | Series PR Operating Partnership Units
Capital:
General partner operating partnership units, outstanding (in shares)	2,852,787	2,996,520
Limited partner operating partnership units, outstanding (in shares)	168,712,617	178,897,876

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Rental revenue	$ 563,071	$ 586,414
Rental revenue			$ 493,231
Tenant expense reimbursement	0	0	72,372
Observatory revenue	29,057	128,769	131,227
Lease termination fees	9,416	4,352	20,847
Third-party management and other fees	1,225	1,254	1,440
Other revenue and fees	6,459	10,554	12,394
Total revenues	609,228	731,343	731,511
Operating expenses:
Property operating expenses	136,141	174,977	167,379
Ground rent expense	9,326	9,326	9,326
General and administrative expenses	62,244	61,063	52,674
Observatory expenses	23,723	33,767	32,767
Real estate taxes	121,923	115,916	110,000
Impairment charges	6,204	0	0
Depreciation and amortization	191,006	181,588	168,508
Total operating expenses	550,567	576,637	540,654
Total operating income	58,661	154,706	190,857
Other income (expense):
Interest income	2,637	11,259	10,661
Interest expense	(89,907)	(79,246)	(79,623)
Loss on early extinguishment of debt	(86)	0	0
IPO litigation expense	(1,165)	0	0
Income (loss) before income taxes	(29,860)	86,719	121,895
Income tax benefit (expense)	6,971	(2,429)	(4,642)
Net income (loss)	(22,889)	84,290	117,253
Private perpetual preferred unit distributions	(4,197)	(1,743)	(936)
Net income (loss) attributable to common unitholders	$ (27,086)	$ 82,547	$ 116,317
Total weighted average units:
Basic (in units)	283,826	297,798	297,258
Diluted (in units)	283,837	297,798	297,259
Net income (loss) per unit:
Basic net income per unit (in dollars per unit)	$ (0.10)	$ 0.27	$ 0.39
Diluted net income per unit (in dollars per unit)	$ (0.10)	$ 0.27	$ 0.39

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ (22,889)	$ 84,290	$ 117,253
Other comprehensive income (loss):
Unrealized gain (loss) on valuation of interest rate swap agreements	(19,322)	(21,813)	(2,721)
Amount reclassified into interest expense	8,870	1,231	1,845
Other comprehensive income (loss)	(10,452)	(20,582)	(876)
Comprehensive income (loss)	$ (33,341)	$ 63,708	$ 116,377

Consolidated Statements of Capi

Consolidated Statements of Capital - USD ($) $ in Thousands	3 Months Ended						12 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance		$ 1,947,913		$ 1,991,109		$ 1,977,737	$ 1,947,913	$ 1,991,109	$ 1,977,737
Issuance of private perpetual preferred in exchange for OP units							0	0
Issuance of OP units, net of costs									4,749
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ 0	0	0
Repurchase of common units (in units)							(17,279,252)
Repurchases of common units							$ (143,713)
Equity compensation							25,495	20,857	18,785
Distributions							(65,047)	(127,761)	(126,539)
Net income	$ 710	$ 8,288	$ 28,720	$ 9,856	$ 39,781	$ 18,058	(22,889)	84,290	117,253
Other comprehensive income (loss)							(10,452)	(20,582)	(876)
Ending balance	$ 1,731,307		$ 1,947,913		$ 1,991,109		$ 1,731,307	$ 1,947,913	$ 1,991,109
General Partner | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		181,894,000		174,912,000		161,477,000	181,894,000	174,912,000	161,477,000
Beginning balance		$ 1,228,520		$ 1,238,482		$ 1,168,282	$ 1,228,520	$ 1,238,482	$ 1,168,282
Issuance of OP units, net (in units)									284,000
Issuance of OP units, net of costs									$ 4,749
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital (in units)							6,807,000	6,929,000	13,127,000
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ 29,863	$ 27,495	$ 70,779
Repurchase of common units (in units)							(17,279,000)
Repurchases of common units							$ (143,713)
Equity compensation (in units)							143,000	53,000	24,000
Equity compensation							$ 921	$ 618	$ 417
Distributions							(37,181)	(75,192)	(70,854)
Net income							(16,712)	49,445	65,603
Other comprehensive income (loss)							$ (6,449)	$ (12,328)	$ (494)
Ending balance (in units)	171,565,000		181,894,000		174,912,000		171,565,000	181,894,000	174,912,000
Ending balance	$ 1,055,249		$ 1,228,520		$ 1,238,482		$ 1,055,249	$ 1,228,520	$ 1,238,482
Limited Partners | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		81,388,000		86,202,000		91,760,000	81,388,000	86,202,000	91,760,000
Beginning balance		$ 680,580		$ 725,108		$ 778,279	$ 680,580	$ 725,108	$ 778,279
Issuance of private perpetual preferred in exchange for OP units (in shares)							(97,000)	(2,488,000)
Issuance of private perpetual preferred in exchange for OP units							$ (800)	$ (20,613)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital (in units)							(3,751,000)	(3,208,000)	(8,168,000)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ (29,803)	$ (26,323)	$ (68,386)
Equity compensation (in units)							2,815,000	882,000	2,610,000
Equity compensation							$ 24,574	$ 20,239	$ 18,368
Distributions							(16,247)	(34,314)	(36,284)
Net income							(7,043)	21,958	33,383
Other comprehensive income (loss)							$ (2,718)	$ (5,475)	$ (252)
Ending balance (in units)	80,355,000		81,388,000		86,202,000		80,355,000	81,388,000	86,202,000
Ending balance	$ 648,543		$ 680,580		$ 725,108		$ 648,543	$ 680,580	$ 725,108
Limited Partners | Series ES Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		25,810,000		30,129,000		33,774,000	25,810,000	30,129,000	33,774,000
Beginning balance		$ 7,262		$ 14,399		$ 17,132	$ 7,262	$ 14,399	$ 17,132
Issuance of private perpetual preferred in exchange for OP units (in shares)							43,000	(1,632,000)
Issuance of private perpetual preferred in exchange for OP units							$ 11	$ (432)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital (in units)							(2,175,000)	(2,687,000)	(3,645,000)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ (92)	$ (918)	$ (1,809)
Distributions							(5,264)	(11,736)	(13,161)
Net income							(2,356)	7,925	12,330
Other comprehensive income (loss)							$ (909)	$ (1,976)	$ (93)
Ending balance (in units)	23,678,000		25,810,000		30,129,000		23,678,000	25,810,000	30,129,000
Ending balance	$ (1,348)		$ 7,262		$ 14,399		$ (1,348)	$ 7,262	$ 14,399
Limited Partners | Series 60 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		7,025,000		8,020,000		8,988,000	7,025,000	8,020,000	8,988,000
Beginning balance		$ 1,593		$ 3,385		$ 3,992	$ 1,593	$ 3,385	$ 3,992
Issuance of private perpetual preferred in exchange for OP units (in shares)							0	(303,000)
Issuance of private perpetual preferred in exchange for OP units							$ 0	$ (63)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital (in units)							(601,000)	(692,000)	(968,000)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ 22	$ (171)	$ (423)
Distributions							(1,435)	(3,169)	(3,532)
Net income							(650)	2,146	3,373
Other comprehensive income (loss)							$ (251)	$ (535)	$ (25)
Ending balance (in units)	6,424,000		7,025,000		8,020,000		6,424,000	7,025,000	8,020,000
Ending balance	$ (721)		$ 1,593		$ 3,385		$ (721)	$ 1,593	$ 3,385
Limited Partners | Series 250 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		3,535,000		4,064,000		4,410,000	3,535,000	4,064,000	4,410,000
Beginning balance		$ 807		$ 1,731		$ 2,048	$ 807	$ 1,731	$ 2,048
Issuance of private perpetual preferred in exchange for OP units (in shares)							0	(187,000)
Issuance of private perpetual preferred in exchange for OP units							$ 0	$ (39)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital (in units)							(280,000)	(342,000)	(346,000)
Conversion of operating partnership units and Class B shares to ESRT Partner's Capital							$ 10	$ (83)	$ (161)
Distributions							(723)	(1,607)	(1,772)
Net income							(325)	1,073	1,628
Other comprehensive income (loss)							$ (125)	$ (268)	$ (12)
Ending balance (in units)	3,255,000		3,535,000		4,064,000		3,255,000	3,535,000	4,064,000
Ending balance	$ (356)		$ 807		$ 1,731		$ (356)	$ 807	$ 1,731
Private Perpetual Preferred Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		6,170,000		1,560,000		1,560,000	6,170,000	1,560,000	1,560,000
Beginning balance		$ 29,151		$ 8,004		$ 8,004	$ 29,151	$ 8,004	$ 8,004
Issuance of private perpetual preferred in exchange for OP units (in shares)							54,000	4,610,000
Issuance of private perpetual preferred in exchange for OP units							$ 789	$ 21,147
Distributions							(4,197)	(1,743)	(936)
Net income							$ 4,197	$ 1,743	$ 936
Ending balance (in units)	6,224,000		6,170,000		1,560,000		6,224,000	6,170,000	1,560,000
Ending balance	$ 29,940		$ 29,151		$ 8,004		$ 29,940	$ 29,151	$ 8,004

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities
Net income (loss)	$ (22,889)	$ 84,290	$ 117,253
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	191,006	181,588	168,508
Impairment charges	6,204	0	0
Amortization of non-cash items within interest expense	9,482	7,328	7,215
Amortization of acquired above and below-market leases, net	(3,627)	(7,311)	(6,120)
Amortization of acquired below-market ground leases	7,831	7,831	7,831
Straight-lining of rental revenue	(5,238)	(20,057)	(22,107)
Equity based compensation	25,495	20,857	18,785
Settlement of derivative contract	(20,281)	(11,802)	0
Loss on early extinguishment of debt	86	0	0
Increase (decrease) in cash flows due to changes in operating assets and liabilities:
Security deposits	(151)	(27,243)	10,717
Tenant and other receivables	3,881	4,015	(1,275)
Deferred leasing costs	(14,464)	(30,895)	(26,899)
Prepaid expenses and other assets	(11,730)	(3,643)	(781)
Accounts payable and accrued expenses	(3,305)	427	1,993
Deferred revenue and other liabilities	19,993	27,206	3,902
Net cash provided by operating activities	182,293	232,591	279,022
Cash Flows From Investing Activities
Short-term investments	0	400,000	(400,000)
Additions to building and improvements and development costs	(143,118)	(250,256)	(243,023)
Net cash (used in) provided by investing activities	(143,118)	149,744	(643,023)
Cash Flows From Financing Activities
Proceeds from mortgage notes payable	180,000	0	160,000
Repayment of mortgage notes payable	(3,938)	(3,790)	(266,613)
Proceeds from unsecured senior notes	175,000	0	335,000
Repayment of unsecured senior notes	0	(250,000)	0
Proceeds from unsecured term loan	175,000	0	0
Repayment of unsecured term loan	(50,000)	0	0
Proceeds from unsecured revolving credit facility	550,000	0	0
Repayment of unsecured revolving credit facility	(550,000)	0	0
Deferred financing costs	(10,135)	0	(1,980)
Net proceeds from the issuance of operating partnership units	0	0	4,749
Repurchases of common units	(143,713)	0	0
Private perpetual preferred unit distributions	(4,197)	(1,743)	(936)
Distributions	(60,850)	(126,018)	(125,603)
Net cash provided by (used in) financing activities	257,167	(381,551)	104,617
Net increase (decrease) in cash and cash equivalents and restricted cash	296,342	784	(259,384)
Cash and cash equivalents and restricted cash—beginning of period	271,597	270,813	530,197
Cash and cash equivalents and restricted cash—end of period	567,939	271,597	270,813
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	233,946	204,981	464,344
Restricted cash at beginning of period	37,651	65,832	65,853
Cash and cash equivalents at end of period	526,714	233,946	204,981
Restricted cash at end of period	41,225	37,651	65,832
Cash and cash equivalents and restricted cash	271,597	270,813	270,813
Supplemental disclosures of cash flow information:
Cash paid for interest	75,416	76,333	74,160
Interest capitalized	0	1,433	1,596
Cash paid for income taxes	1,282	1,766	4,847
Non-cash investing and financing activities:
Building and improvements included in accounts payable and accrued expenses	58,057	90,910	85,242
Write-off of fully depreciated assets	79,527	30,977	39,665
Conversion of operating partnership units and Class B shares to Class A shares	29,863	27,495	70,779
Issuance of Series 2019 private perpetual preferred in exchange for operating partnership units	789	21,147	$ 0
Right of use assets	0	29,452
Ground lease liabilities	$ 0	$ 29,452

Description of Business and Org

Description of Business and Organization	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Organization	Description of Business and Organization As used in these consolidated financial statements, unless the context otherwise requires, “we,” “us,” "our," and the "company,” mean Empire State Realty OP, L.P. and its consolidated subsidiaries. Empire State Realty OP, L.P. is the entity through which Empire State Realty Trust, Inc. ("ESRT"), a self-administered and self-managed real estate investment trust, or REIT, conducts all of its business and owns (either directly or through subsidiaries) substantially all of its assets. We own, manage, operate, acquire and reposition office and retail properties in Manhattan and the greater New York metropolitan area. Empire State Realty Trust, Inc.'s Class A common stock, par value $0.01 per share, is listed on the New York Stock Exchange under the symbol "ESRT." We were organized as a Delaware limited partnership on November 28, 2011. ESRT as the sole general partner in our company, has responsibility and discretion in the management and control in our company, and our limited partners, in such capacity, have no authority to transact business for, or participate in the management activities of our company. As of December 31, 2020, ESRT owned approximately 60.1% of our operating partnership units. As of December 31, 2020, our total portfolio contained 10.1 million rentable square feet of office and retail space. We owned 14 office properties (including three long-term ground leasehold interest) encompassing approximately 9.4 million rentable square feet of office space. Nine of these properties are located in the midtown Manhattan market and encompass in the aggregate approximately 7.6 million rentable square feet of office space, including the Empire State Building. Our Manhattan office properties also contain an aggregate of 0.5 million rentable square feet of premier retail space on their ground floor and/or lower levels. Our remaining five office properties are located in Fairfield County, Connecticut and Westchester County, New York, encompassing in the aggregate approximately 1.8 million rentable square feet. The majority of square footage for these five properties is located in densely populated metropolitan communities with immediate access to mass transportation. Additionally, we have entitled land at the Stamford Transportation Center in Stamford, Connecticut, adjacent to one of our office properties, that will support the development of an approximately 0.4 million rentable square foot office building and garage, which we refer to herein as Metro Tower. As of December 31, 2020, our portfolio also included four standalone retail properties located in Manhattan and two standalone retail properties located in the city center of Westport, Connecticut, encompassing 0.2 million rentable square feet in the aggregate.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements, have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and with the rules and regulations of the Securities and Exchange Commission (the "SEC"), represent our assets and liabilities and operating results. The consolidated financial statements include our accounts and our wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. 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 as well as whether the entity is a variable interest entity (“VIE”) and whether we are 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. We had no VIEs as of December 31, 2020 and 2019. 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 consolidated balance sheets and in the 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 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, goodwill, right-of-use-assets and other long-lived assets, estimate of tenant expense reimbursements, valuation of the allowance for doubtful accounts, and valuation of derivative instruments, ground lease liabilities, senior unsecured notes, mortgage notes payable, unsecured revolving credit and term loan 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. Revenue Recognition Rental Revenue Rental revenue includes base rents that each tenant pays in accordance with the terms of its respective lease and is reported on a straight-line basis over the non-cancellable term of the lease which includes the effects of rent steps and rent abatements under the leases. In general, we commence rental revenue recognition when the tenant takes possession of the leased space or controls the physical use of the leased space and the leased space is substantially ready for its intended use. We account for all of our leases as operating leases. Deferred rent receivables, including free rental periods and leasing arrangements allowing for increased base rent payments, are accounted for in a manner that provides an even amount of fixed lease revenues over the respective non-cancellable lease terms. Differences between rental income recognized and amounts due under the respective lease agreements are recognized as an increase or decrease to deferred rent receivables. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in an index such as the Consumer Price Index over the index value in effect during a base year, or contain fixed percentage increases over the base rent to cover escalations. For Coronavirus 2019 (“COVID-19”) pandemic related rent deferral agreements, we will generally elect to record rental revenue and a receivable during the deferral period. We recognize rental revenue of acquired in-place above- and below-market leases at their fair values over the terms of the respective leases, including, for below-market leases, fixed option renewal periods, if any. Lease termination fees are recognized when the fees are determinable, tenant vacancy has occurred, collectability is reasonably assured, we have no continuing obligation to provide services to such former tenants and the payment is not subject to any conditions that must be met or waived. Observatory Revenue Revenues from the sale of Observatory tickets are recognized upon admission or ticket expirations. Deferred revenue related to unused and unexpired tickets as of December 31, 2020 and 2019 was $0.8 million and $2.7 million, respectively, and is included in deferred revenue and other liabilities on the consolidated balance sheets. Gains on Sale of Real Estate We record a gain on sale of real estate pursuant to provisions under Accounting Standards Codification (ASC) 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets. Under ASC 610-20, we must first determine whether the transaction is a sale to a customer or non-customer. We do not sell real estate within the ordinary course of our business and therefore, expect that sale transactions will not be contracts with customers. We will next determine whether we would have a controlling financial interest in the property after the sale. If we determine that we do not have a controlling financial interest in the real estate, we would evaluate whether a contract exists under ASC 606 Revenue from Contracts with Customers and whether the buyer has obtained control of the asset that was sold. We recognize the full gain on sale of real estate when the derecognition criteria under ASC 610-20 have been met. Third-Party Management and Other Fees We earn revenue arising from contractual agreements with related party entities for asset and property management services. This revenue is recognized as the related services are performed under the respective agreements in place. Other Revenues and Fees Other revenues and fees includes parking income, legal, tax and insurance settlements, demand response energy use earnings and sales from our restaurant at the Empire State Building. Advertising and Marketing Costs Advertising and marketing costs are expensed as incurred. The expense for the years ended December 31, 2020, 2019, and 2018 was $7.4 million, $9.7 million and $8.9 million, respectively, and is included within operating expenses in our consolidated statements of operations. Real Estate Properties and Related Intangible Assets Land and buildings and improvements are recorded at cost less accumulated depreciation and amortization. The recorded cost includes cost of acquisitions, development and construction and tenant allowances and improvements. Expenditures for ordinary repairs and maintenance are charged to property operating expense as incurred. Significant replacements and betterments which improve or extend the life of the asset are capitalized. Tenant improvements which improve or extend the life of the asset are capitalized. If a tenant vacates its space prior to the contractual termination of its lease, the unamortized balance of any tenant improvements are written off if they are replaced or have no future value. For developed properties, direct and indirect costs that clearly relate to projects under development are capitalized. Costs include construction costs, professional services such as architectural and legal costs, capitalized interest and direct payroll costs. We begin capitalization when the project is probable. The assets relating to the project are stated at cost and are not depreciated. Once construction is completed and the assets are placed in service, the assets are reclassified to the appropriate asset class and depreciated in accordance with the useful lives as indicated below. Capitalization of interest ceases when the asset is ready for its intended use, which is generally near the date that a certificate of occupancy is obtained. Total capitalized interest for the years ended December 31, 2019 and 2018 was $1.4 million and $1.6 million, respectively. There was no capitalized interest for the year ended December 31, 2020. Depreciation and amortization are computed using the straight-line method for financial reporting purposes. Buildings and improvements are depreciated over the shorter of 39 years, the useful life, or the remaining term of any leasehold interest. Tenant improvement costs, which are included in building and improvements in the consolidated balance sheets, are depreciated over the shorter of (i) the related remaining lease term or (ii) the life of the improvement. Corporate equipment, which is included in “Other assets,” is depreciated over three Acquisitions of properties are accounted for utilizing the acquisition method and accordingly the purchase cost is allocated to tangible and intangible assets and liabilities based on their fair values. The fair value of tangible assets acquired is determined by valuing the property as if it were vacant, applying methods similar to those used by independent appraisers of income-producing property. The resulting value is then allocated to land, buildings and improvements, and tenant improvements based on our determination of the fair value of these assets. The assumptions used in the allocation of fair values to assets acquired are based on our best estimates at the time of evaluation. Fair value is assigned to above-market and below-market leases based on the difference between (a) the contractual amounts to be paid by the tenant based on the existing lease and (b) our estimate of current market lease rates for the corresponding in-place leases, over the remaining terms of the in-place leases. Capitalized above-market lease amounts are amortized as a decrease to rental revenue over the remaining terms of the respective leases. Capitalized below-market lease amounts are amortized as an increase to rental revenue over the remaining terms of the respective leases. If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The aggregate value of other acquired intangible assets consists of acquired ground leases and acquired in-place leases and tenant relationships. The fair value allocated to acquired in-place leases consists of a variety of components including, but not necessarily limited to: (a) the value associated with avoiding the cost of originating the acquired in-place leases (i.e. the market cost to execute a lease, including leasing commissions, if any); (b) the value associated with lost revenue related to tenant reimbursable operating costs estimated to be incurred during the assumed lease-up period (i.e. real estate taxes, insurance and other operating expenses); (c) the value associated with lost rental revenue from existing leases during the assumed lease-up period; and (d) the value associated with any other inducements to secure a tenant lease. We assess the potential for impairment of our long-lived assets, including real estate properties, annually or whenever events occur or a change in circumstances indicate that the recorded value might not be fully recoverable. We determine whether impairment in value has occurred by comparing the estimated future undiscounted cash flows expected from the use and eventual disposition of the asset to its carrying value. If the undiscounted cash flows do not exceed the carrying value, the real estate is adjusted to fair value and an impairment loss is recognized. Assets held for sale are recorded at the lower of cost or fair value less costs to sell. We do not believe that the value of any of our properties and intangible assets were impaired during the years ended December 31, 2020, 2019 and 2018. Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand, government money markets, demand deposits with financial institutions and short-term liquid investments with original maturities of three months or less when purchased. Cash and cash equivalents held at major commercial banks may at times exceed the Federal Deposit Insurance Corporation limit. To date, we have not experienced any losses on our invested cash. Restricted Cash Restricted cash consists of amounts held for tenants in accordance with lease agreements such as security deposits and amounts held by lenders and/or escrow agents to provide for future real estate tax expenditures and insurance expenditures, tenant vacancy related costs and debt service obligations. Short-term Investments Short-term investments include time deposits with original maturities of greater than three months and remaining maturities of less than one year. Tenant and Other Receivables Tenant and other receivables, other than deferred rent receivable, are generally expected to be collected within one year. Deferred Leasing Costs Deferred leasing costs consist of fees incurred to initiate and renew leases, are amortized on a straight-line basis over the related lease term and the expense is included in depreciation and amortization in our consolidated statements of income. Upon the early termination of a lease, unamortized deferred leasing costs are charged to expense. Deferred Financing Costs Fees and costs incurred to obtain long-term financing have been deferred and are amortized as a component of interest expense in our consolidated statements of income over the life of the respective long-term financing on the straight-line method which approximates the effective interest method. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking debt, which do not close, are expensed in the period in which it is determined that the financing will not close. Equity Method Investments We account for investments under the equity method of accounting where we do not have control but have the ability to exercise significant influence. Under this method, investments are recorded at cost, and the investment accounts are adjusted for our share of the entities’ income or loss and for distributions and contributions. Equity income (loss) is allocated based on the portion of the ownership interest that is controlled by us. The agreements may designate different percentage allocations among investors for profits and losses; however, our recognition of the entity’s income or loss generally follows the entity’s distribution priorities, which may change upon the achievement of certain investment return thresholds. To the extent that we contributed assets to an entity, our investment in the entity is recorded at cost basis in the assets that were contributed to the entity. Upon contributing assets to an entity, we make a judgment as to whether the economic substance of the transaction is a sale. In accordance with the provisions of ASC 610-20, we will recognize a full gain on both the retained and sold portions of real estate contributed or sold to an entity by recognizing our new equity method investment interest at fair value. To the extent that the carrying amount of these investments on our combined balance sheets is different than the basis reflected at the entity level, the basis difference would be amortized over the life of the related asset and included in our share of equity in net income of the entity. On a periodic basis, we assess whether there are any indicators that the carrying value of our investments in entities may be impaired on an other than temporary basis. An investment is impaired only if management’s estimate of the fair value of the investment is less than the carrying value of the investment on an other than temporary basis. To the extent impairment has occurred, the loss shall be measured as the excess of the carrying value of the investment over the fair value of the investment. As of December 31, 2020 and 2019, we had no equity method investments. Goodwill Goodwill is tested annually for impairment and is tested for impairment more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount, including goodwill, exceeds the reporting unit’s fair value and the implied fair value of goodwill is less than the carrying amount of that goodwill. Non-amortizing intangible assets, such as trade names and trademarks, are subject to an annual impairment test based on fair value and amortizing intangible assets are tested whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. In compliance with the requirements of authorities, we closed the Empire State Building Observatory on March 16, 2020 due to the COVID-19 pandemic and it remained closed until the 86th floor observation deck was reopened on July 20, 2020. The 102nd observation deck was reopened on August 24, 2020. The closure of our Observatory and subsequent reopening under international, national, and local travel restrictions and quarantines caused us during the quarter to choose to perform an impairment test related to goodwill. We engaged a third-party valuation consulting firm to perform the valuation process. The analysis used a combination of the discounted cash flow method (a form of the income approach) utilizing Level 3 unobservable inputs and the guideline company method (a form of the market approach). Significant assumptions under the former included revenue and cost projections, weighted average cost of capital, long-term growth rate and income tax considerations while the latter included guideline company enterprise values, revenue multiples and control premium rates. Our methodology to review goodwill impairment, which included a significant amount of judgment and estimates, provided a reasonable basis to determine whether impairment had occurred. Based upon the results of the goodwill impairment test of the stand-alone Observatory reporting unit, which is after the intercompany rent expense paid to the Real Estate reporting unit, we determined that the fair value of the Observatory reporting unit exceeded its carrying value by less than 5.0%. Many of the factors employed in determining whether or not goodwill is impaired are outside of our control and it is reasonably likely that assumptions and estimates will change in future periods. We will continue to assess the impairment of the Observatory reporting unit goodwill going forward and that continued assessment may again utilize a third-party valuation consulting firm. Fair Value Fair value is a market-based measurement, not an entity-specific measurement, and should be determined based on the assumptions that market participants would use in pricing the asset or liability. As a basis for considering market participant assumptions in fair value measurements, the FASB guidance establishes a fair value hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within levels one and two of the hierarchy) and the reporting entity's own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy). The methodologies used for valuing financial instruments have been categorized into three broad levels as follows: Level 1 - Quoted prices in active markets for identical instruments. Level 2 - Valuations based principally on other observable market parameters, including: • Quoted prices in active markets for similar instruments; • Quoted prices in less active or inactive markets for identical or similar instruments; • Other observable inputs (such as risk free interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates); and • Market corroborated inputs (derived principally from or corroborated by observable market data). Level 3 - Valuations based significantly on unobservable inputs, including: • Valuations based on third-party indications (broker quotes or counterparty quotes) which were, in turn, based significantly on unobservable inputs or were otherwise not supportable; and • Valuations based on internal models with significant unobservable inputs. These levels form a hierarchy. We follow this hierarchy for our financial instruments measured or disclosed at fair value on a recurring and nonrecurring basis and other required fair value disclosures. The classifications are based on the lowest level of input that is significant to the fair value measurement. We use the following methods and assumptions in estimating fair value disclosures for financial instruments. Cash and cash equivalents, restricted cash, short term investments, tenant and other receivables, prepaid expenses and other assets, deferred revenue, tenant security deposits, accounts payable and accrued expenses carrying values approximate their fair values due to the short term maturity of these instruments. The fair value of derivative instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Although the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by ourselves and our counterparties. The impact of such credit valuation adjustments, determined based on the fair value of each individual contract, was not significant to the overall valuation. As a result, all of our derivatives were classified as Level 2 of the fair value hierarchy. The fair value of our mortgage notes payable, senior unsecured notes - Series A, B, C, D, E, F, G and H, and unsecured term loan facilities which are determined using Level 3 inputs, are estimated by discounting the future cash flows using current interest rates at which similar borrowings could be made to us. Derivative Instruments We are exposed to the effect of interest rate changes and manage these risks by following policies and procedures including the use of derivatives. To manage exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices. We also hedged our exposure to the variability in future cash flows for forecast transactions through June 30, 2020 (excluding forecast transactions related to the payment of variable interest on existing financial instruments). We record all derivatives on the balance sheet at fair value. We incorporate credit valuation adjustments to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. We measure the credit risk of our derivative instruments that are subject to master netting agreements on a net basis by counterparty portfolio. For derivatives that qualify as cash flow hedges, we report the gain or loss on the derivative designated as a hedge as part of other comprehensive income (loss) and subsequently reclassify the gain or loss into income in the period that the hedged transaction affects income. Income Taxes We are generally not subject to federal and state income taxes as our taxable income or loss is reportable by our partners. Accordingly, no provision has been made for federal and state income taxes. ESRT has elected, together with ESRT Observatory TRS, L.L.C., our subsidiary which holds our observatory operations, to treat ESRT Observatory TRS, L.L.C. as a TRS. ESRT has elected, together with ESRT Holdings TRS, L.L.C., our subsidiary that holds our third party management, restaurant, cafeteria, health clubs and certain cleaning operations, to treat ESRT Holdings TRS, L.L.C. as a TRS. TRSs may participate in non-real estate activities and/or perform non-customary services for tenants and their operations are generally subject to regular corporate income taxes. Our TRSs account for their income taxes in accordance with GAAP, which includes an estimate of the amount of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in our financial statements or tax returns. The calculation of the TRSs' tax provisions may require interpreting tax laws and regulations and could result in the use of judgments or estimates which could cause its recorded tax liability to differ from the actual amount due. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The TRSs periodically assess the realizability of deferred tax assets and the adequacy of deferred tax liabilities, including the results of local, state, or federal statutory tax audits or estimates and judgments used. We apply provisions for measuring and recognizing tax benefits associated with uncertain income tax positions. Penalties and interest, if incurred, would be recorded as a component of income tax expense. As of December 31, 2020 and 2019, we do not have a liability for uncertain tax positions. As of December 31, 2020, the tax years ended December 31, 2017 through December 31, 2020 remain open for an audit by the Internal Revenue Service, state or local authorities. Share-Based Compensation Share-based compensation for market based equity awards is measured at the fair value of the award on the date of grant and recognized as an expense on a straight-line basis over the stated vesting period, which is generally three or four years, depending on retirement eligibility. Share-based compensation for time-based equity awards is measured at the fair value of the award on the date of grant and recognized as an expense on a straight-line basis over the shorter of (i) the stated vesting period, which is generally three or four years, or (ii) the period from the date of grant to the date the employee becomes retirement eligible, which may occur upon grant. An employee is retirement eligible when the employee attains the (i) age of 60 or 65, as applicable, and (ii) the date on which the employee has first completed ten years of continuous service with ESRT or its affiliates. The determination of fair value of these awards is subjective and involves significant estimates and assumptions including expected volatility of ESRT stock, expected dividend yield, expected term, and assumptions of whether these awards will achieve parity with other operating partnership units or achieve performance thresholds. We believe that the assumptions and estimates utilized are appropriate based on the information available to management at the time of grant. Per Unit Data Basic and diluted earnings per unit are computed based upon the weighted average number of shares outstanding during the respective period. Segment Reporting We have identified two reportable segments: (1) Real Estate and (2) Observatory. Our real estate segment includes all activities related to the ownership, management, operation, acquisition, repositioning and disposition of our real estate assets. Our observatory segment operates the 86th and 102nd floor observatories at the Empire State Building. These two lines of businesses are managed separately because each business requires different support infrastructures, provides different services and has dissimilar economic characteristics such as investments needed, stream of revenues and different marketing strategies. We account for intersegment sales and rent as if the sales or rent were to third parties, that is, at current market prices. Recently Issued or Adopted Accounting Standards During April 2020, the Financial Accounting Standards Board ("FASB") staff issued a question and answer document (the “Lease Modification Q&A”) focused on the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 global pandemic. Under existing lease guidance, the entity would have to determine, on a lease by lease basis, if a lease concession was the result of a new arrangement reached with the tenant, which would be accounted for under the lease modification framework, or if a lease concession was under the enforceable rights and obligations that existed in the original lease, which would be accounted for outside the lease modification framework. The Lease Modification Q&A provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. During March 2020, the FASB issued Accounting Standards Update ("ASU") 2020-04, Reference Rate Reform (Topic 848). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the first quarter 2020, we elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. During January 2017, the FASB issued 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 b

Deferred Costs, Acquired Lease

Deferred Costs, Acquired Lease Intangibles and Goodwill	12 Months Ended
	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs, Acquired Lease Intangibles and Goodwill	Deferred Costs, Acquired Lease Intangibles and Goodwill Deferred costs, net, consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Leasing costs $ 203,905 $ 199,033 Acquired in-place lease value and deferred leasing costs 181,336 200,296 Acquired above-market leases 40,398 49,213 425,639 448,542 Less: accumulated amortization (223,918) (224,598) Total deferred costs, net, excluding net deferred financing costs $ 201,721 $ 223,944 At December 31, 2020 and 2019, $2.1 million and $4.2 million, respectively, of net deferred financing costs associated with the unsecured revolving credit facility was included in deferred costs, net on the consolidated balance sheets. Amortization expense related to deferred leasing and acquired deferred leasing costs was $24.8 million, $24.5 million, and $26.3 million, for the years ended December 31, 2020, 2019, and 2018, respectively. Amortization expense related to acquired lease intangibles was $7.6 million, $10.9 million and $12.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. Amortizing acquired intangible assets and liabilities consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (52,181) (44,350) Acquired below-market ground leases, net $ 344,735 $ 352,566 2020 2019 Acquired below-market leases $ (78,451) $ (100,472) Less: accumulated amortization 46,746 60,793 Acquired below-market leases, net $ (31,705) $ (39,679) Rental revenue related to the amortization of below market leases, net of above market leases was $3.6 million, $7.3 million and $6.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. The remaining weighted-average amortization period as of December 31, 2020 is 23.6 years, 3.9 years, 3.6 years and 3.7 years for below-market ground leases, in-place leases and deferred leasing costs, above-market leases and below-market leases, respectively. We expect to recognize amortization expense and rental revenue from the acquired intangible assets and liabilities as follows (amounts in thousands): For the year ending: Future Ground Rent Amortization Future Amortization Expense Future Rental Revenue 2021 $ 7,831 $ 10,977 $ 2,850 2022 7,831 10,175 3,169 2023 7,831 9,622 3,129 2024 7,831 7,757 2,566 2025 7,831 6,652 2,558 Thereafter 305,580 16,740 4,082 $ 344,735 $ 61,923 $ 18,354 As of December 31, 2020, we had goodwill of $491.5 million. In 2013, we acquired the interests in Empire State Building Company, L.L.C. and 501 Seventh Avenue Associates, L.L.C. for an amount in excess of their net tangible and identified intangible assets and liabilities and as a result we recorded goodwill related to the transaction. Goodwill was allocated $227.5 million to the observatory operations of the Empire State Building, $250.8 million to Empire State Building, and $13.2 million to 501 Seventh Avenue. In compliance with the requirements of authorities, we closed the Empire State Building Observatory on March 16, 2020 due to the COVID-19 pandemic and it remained closed until the 86th floor observation deck was reopened on July 20, 2020. The 102nd observation deck was reopened on August 24, 2020. The closure of our Observatory and subsequent

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following as of December 31, 2020 and 2019 (amounts in thousands): As of December 31, 2020 Principal Balance as Principal Balance as Stated Effective (1) Maturity (2) Fixed rate mortgage debt Metro Center $ 87,382 $ 89,650 3.59 % 3.68 % 11/5/2024 10 Union Square 50,000 50,000 3.70 % 3.97 % 4/1/2026 1542 Third Avenue 30,000 30,000 4.29 % 4.53 % 5/1/2027 First Stamford Place (3) 180,000 180,000 4.28 % 4.78 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,477 38,251 4.01 % 4.23 % 1/5/2028 250 West 57th Street 180,000 — 2.83 % 3.27 % 12/1/2030 10 Bank Street 32,025 32,920 4.23 % 4.36 % 6/1/2032 383 Main Avenue 30,000 30,000 4.44 % 4.55 % 6/30/2032 1333 Broadway 160,000 160,000 4.21 % 4.29 % 2/5/2033 Total mortgage debt 786,884 610,821 Senior unsecured notes: (4) Series A 100,000 100,000 3.93 % 3.96 % 3/27/2025 Series B 125,000 125,000 4.09 % 4.12 % 3/27/2027 Series C 125,000 125,000 4.18 % 4.21 % 3/27/2030 Series D 115,000 115,000 4.08 % 4.11 % 1/22/2028 Series E 160,000 160,000 4.26 % 4.27 % 3/22/2030 Series F 175,000 175,000 4.44 % 4.45 % 3/22/2033 Series G 100,000 — 3.61 % 4.89 % 3/17/2032 Series H 75,000 — 3.73 % 5.00 % 3/17/2035 Unsecured revolving credit facility (4) — — LIBOR plus 1.10% — % 8/29/2021 Unsecured term loan facility (4) 215,000 265,000 LIBOR plus 1.20% 3.84 % 3/19/2025 Unsecured term loan facility (4) 175,000 — LIBOR plus 1.50% 3.04 % 12/31/2026 Total principal 2,151,884 1,675,821 Deferred financing costs, net (15,235) (7,247) Total $ 2,136,649 $ 1,668,574 _____________ (1) The effective rate is the yield as of December 31, 2020, including the effects of debt issuance costs and interest rate swaps. (2) Pre-payment is generally allowed for each loan upon payment of a customary pre-payment penalty. (3) Represents a $164 million mortgage loan bearing interest of 4.09% and a $16 million loan bearing interest at 6.25%. (4) At December 31, 2020, we were in compliance with all debt covenants. Principal Payments Aggregate required principal payments at December 31, 2020 are as follows (amounts in thousands): Year Amortization Maturities Total 2021 $ 4,090 $ — $ 4,090 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 2025 5,826 315,000 320,826 Thereafter 20,084 1,707,747 1,727,831 Total principal maturities $ 51,462 $ 2,100,422 $ 2,151,884 Deferred Financing Costs Deferred financing costs, net, consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Financing costs $ 35,365 $ 25,315 Less: accumulated amortization (17,998) (13,863) Total deferred financing costs, net $ 17,367 $ 11,452 At December 31, 2020 and 2019, $2.1 million and $4.2 million, respectively, of net deferred financing costs associated with the unsecured revolving credit facility were included in deferred costs, net on the consolidated balance sheet. Amortization expense related to deferred financing costs was $4.1 million, $3.8 million, and $4.1 million, for the years ended December 31, 2020, 2019 and 2018, respectively, and was included in interest expense. Mortgage Debt During November 2020, we closed on a $180.0 million mortgage loan for 250 West 57th Street. This new interest-only loan bears a fixed interest rate of 2.83% and matures in December 2030. Unsecured Revolving Credit and Term Loan Facilities On March 19, 2020, we entered into an amendment to an existing credit agreement with the lenders party thereto, Bank of America, N.A., as administrative agent, and Bank of America, Wells Fargo Bank, National Association and Capital One, National Association, as the letter of credit issuers party thereto. The amendment amends the amended and restated senior unsecured revolving credit and term loan facility, entered into as of August 29, 2017, with Bank of America, N.A., as administrative agent, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Wells Fargo Securities, LLC as Joint Lead Arrangers and Joint Bookrunners, Wells Fargo, National Association and Capital One, National Association, as co-syndication agents, and the lenders party thereto. This new amended and restated senior unsecured revolving credit and term loan facility (the "Credit Facility") is in the original principal amount of up to $1.315 billion, which consists of a $1.1 billion revolving credit facility and a $215.0 million term loan facility. We borrowed the term loan facility in full at closing. We may request the Credit Facility be increased through one or more increases in the revolving credit facility or one or more increases in the term loan facility or the addition of new pari passu term loan tranches, for a maximum aggregate principal amount not to exceed $1.75 billion. As of December 31, 2020, we had no borrowings under the revolving credit facility and $215.0 million outstanding under the term loan facility. The initial maturity of the unsecured revolving credit facility is August 2021. We have the option to extend the initial term for up to two additional 6-month periods, subject to certain conditions, including the payment of an extension fee equal to 0.0625% and 0.075% of the then outstanding commitments under the unsecured revolving credit facility on the first and the second extensions, respectively. We recently began a process to recast the credit facility and exercise an extension option. The term loan facility matures in March 2025. We may prepay the loans under the Credit Facility at any time in whole or in part, subject to reimbursement of the lenders’ breakage and redeployment costs in the case of prepayment of Eurodollar Rate borrowings. On March 19, 2020, we entered into a senior unsecured term loan facility (the “Term Loan Facility”) with Wells Fargo Bank, National Association, as administrative agent, Wells Fargo Securities, LLC as sole bookrunner, Wells Fargo Securities, LLC, Capital One, National Association, U.S. Bank National Association and SunTrust Robinson Humphrey, Inc. as Joint Lead Arrangers, Capital One, National Association, as syndication agent, U.S. Bank National Association and Truist Bank, as documentation agents, and the lenders party thereto. The Term Loan Facility is in the original principal amount of $175 million which we borrowed in full at closing. We may request the Term Loan Facility be increased through one or more increases or the addition of new pari passu term loan tranches, for a maximum aggregate principal amount not to exceed $225 million. As of December 31, 2020, our borrowings amounted to $175.0 million under the Term Loan Facility. The Term Loan Facility matures on December 31, 2026. We may prepay loans under the Term Loan Facility at any time in whole or in part, subject to reimbursement of the lenders’ breakage and redeployment costs in the case of prepayment of Eurodollar rate borrowings and, if the prepayment occurs on or before December 31, 2021, a prepayment fee. If the prepayment occurs on or prior to December 31, 2020, the prepayment fee is equal to 2.0% of the principal amount prepaid, and if the prepayment occurs after December 31, 2020 but on or prior to December 31, 2021, the prepayment fee is equal to 1.0% of the principal amount prepaid. The terms of both the Credit Facility and the Term Loan Facility include customary covenants, including limitations on liens, investment, distributions, debt, fundamental changes, and transactions with affiliates and require certain customary financial reports. It also requires compliance with financial ratios including a maximum leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, a minimum unencumbered interest coverage ratio, and a maximum unsecured leverage ratio. The agreement also contains customary events of default (subject in certain cases to specified cure periods), including but not limited to non-payment, breach of covenants, representations or warranties, cross defaults, bankruptcy or other insolvency events, judgments, ERISA events, invalidity of loan documents, loss of real estate investment trust qualification, and occurrence of a change of control. As of December 31, 2020, we were in compliance with the covenants under the Credit Facility and the Term Loan Facility. Senior Unsecured Notes Exchangeable During August 2014, we issued $250.0 million principal amount of 2.625% Exchangeable Senior Notes (“2.625% Exchangeable Senior Notes”) due August 15, 2019. The 2.625% Exchangeable Senior Notes were exchangeable into cash, shares of Class A common stock or a combination of cash and shares of Class A common stock, at our election. On August 15, 2019, we settled the principal amount of the 2.625% Exchangeable Senior Notes in cash. For the years ended December 31, 2019 and 2018, total interest expense related to the 2.625% Exchangeable Senior Notes was $6.1 million and $9.9 million, respectively, consisting of (i) contractual interest expense of $4.1 million and $6.6 million, respectively, (ii) additional non-cash interest expense of $1.6 million and $2.7 million, respectively, related to the accretion of the debt discount, and (iii) amortization of deferred financing costs of $0.4 million and $0.6 million, respectively. Senior Unsecured Notes On March 17, 2020, we entered into an agreement to issue and sell an aggregate $175 million of senior unsecured notes, consisting of (a) $100 million aggregate principal amount of 3.61% Series G Senior Notes due March 17, 2032 (the “Series G Notes”) and (b) $75 million aggregate principal amount of 3.73% Series H Senior Notes due March 17, 2035 (the “Series H Notes”). The issue price for the Series G and H Notes was 100% of the aggregate principal amount thereof. The terms of the Series A, B, C, D, E, F, G and H Notes agreements include customary covenants, including limitations on liens, investment, distributions, debt, fundamental changes, and transactions with affiliates and require certain customary financial reports. It also requires compliance with financial ratios including a maximum leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, a minimum unencumbered interest coverage ratio, and a maximum unsecured leverage ratio. The agreement also contains customary events of default (subject in certain cases to specified cure periods), including but not limited to non-payment, breach of covenants, representations or warranties, cross defaults, bankruptcy or other insolvency events, judgments, ERISA events, the occurrence of certain change of control

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts Payable and Accrued Expenses Accounts payable and accrued expenses consist of the following as of December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Accrued capital expenditures $ 58,057 $ 90,910 Accounts payable and accrued expenses 32,309 35,084 Interest rate swap agreements liability 8,849 13,330 Accrued interest payable 3,219 3,699 Due to affiliated companies 769 763 Total accounts payable and accrued expenses $ 103,203 $ 143,786

Financial Instruments and Fair

Financial Instruments and Fair Values	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Values	Financial Instruments and Fair Values Derivative Financial Instruments We use derivative financial instruments primarily to manage interest rate risk and such derivatives are not considered speculative. These derivative instruments are typically in the form of interest rate swap and forward agreements and the primary objective is to minimize interest rate risks associated with investing and financing activities. The counterparties of these arrangements are major financial institutions with which we may also have other financial relationships. We are exposed to credit risk in the event of non-performance by these counterparties; however, we currently do not anticipate that any of the counterparties will fail to meet their obligations. We have agreements with our derivative counterparties that contain a provision where if we either default or are capable of being declared in default on any of our indebtedness, then we could also be declared in default on our derivative obligations. As of December 31, 2020, the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $8.9 million. If we had breached any of these provisions at December 31, 2020, we could have been required to settle our obligations under the agreements at their termination value of $8.9 million. As of December 31, 2020 and 2019, we had interest rate LIBOR swaps with an aggregate notional value of $265.0 million and $390.0 million, respectively. The notional value does not represent exposure to credit, interest rate or market risks. As of December 31, 2020 and 2019, the fair value of our derivative instruments amounted to ($8.8 million) and ($13.3 million), respectively, which is included in accounts payable and accrued expenses on the consolidated balance sheet. These interest rate swaps have been designated as cash flow hedges and hedge the variability in future cash flows associated with our existing variable-rate term loan facilities. As of December 31, 2020 and 2019, our cash flow hedges are deemed highly effective and for the years ended December 31, 2020 and 2019, net unrealized losses of $10.5 million and $20.6 million, respectively, are reflected in the consolidated statements of comprehensive income (loss) relating to both active and terminated cash flow hedges of interest rate risk. Amounts reported in accumulated other comprehensive income (loss) related to derivatives will be reclassified to interest expense as interest payments are made on the debt. We estimate that $11.5 million net loss of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense within the next 12 months. The table below summarizes the terms of agreements and the fair values of our derivative financial instruments as of December 31, 2020 and 2019 (dollar amounts in thousands): December 31, 2020 December 31, 2019 Derivative Notional Amount Receive Rate Pay Rate Effective Date Expiration Date Asset Liability Asset Liability Interest rate swap $ 265,000 1 Month LIBOR 2.1485 % August 31, 2017 August 24, 2022 $ — $ (8,849) $ — $ (4,247) Interest rate swap 125,000 3 Month LIBOR 2.9580 % July 1, 2019 July 1, 2026 — — — (9,083) $ — $ (8,849) $ — $ (13,330) During the year ended December 31, 2020, we terminated the $125.0 million swap and paid a settlement fee of $20.3 million. The table below shows the effect of our derivative financial instruments designated as cash flow hedges on accumulated other comprehensive income (loss) for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): Effects of Cash Flow Hedges December 31, 2020 December 31, 2019 December 31, 2018 Amount of gain (loss) recognized in other comprehensive income (loss) $ (19,322) $ (21,813) $ (2,721) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (8,870) (1,231) (1,845) The table below shows the effect of our derivative financial instruments designated as cash flow hedges on the consolidated statements of income for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): Effects of Cash Flow Hedges December 31, 2020 December 31, 2019 December 31, 2018 Total interest (expense) presented on the consolidated $ (89,907) $ (79,246) $ (79,623) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (8,870) (1,231) (1,845) Fair Valuation The estimated fair values at December 31, 2020 and 2019 were determined by management, using available market information and appropriate valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts we could realize on disposition of the financial instruments. The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. The following tables summarize the carrying and estimated fair values of our financial instruments as of December 31, 2020 and 2019 (amounts in thousands): December 31, 2020 Carrying Value Estimated Fair Value Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses $ 8,849 $ 8,849 $ — $ 8,849 $ — Mortgage notes payable 775,929 808,294 — — 808,294 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,159 1,039,857 — — 1,039,857 Unsecured term loan facilities 387,561 390,000 — — 390,000 December 31, 2019 Carrying Value Estimated Fair Value Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses 13,330 13,330 — 13,330 — Mortgage notes payable 605,542 629,609 — — 629,609 Senior unsecured notes - Series A, B, C, D, E and F 798,392 843,394 — — 843,394 Unsecured term loan facility 264,640 265,000 — — 265,000

Leases Leases

Leases Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one Rental revenue includes fixed and variable payments. Fixed payments primarily relate to base rent and variable payments primarily relate to tenant expense reimbursements for certain property operating costs. The components of rental revenue for the year ended December 31, 2020 and 2019 are as follows (amounts in thousands): Year Ended December 31, 2020 2019 Fixed payments $ 496,515 $ 510,799 Variable payments 66,556 75,615 Total rental revenue $ 563,071 $ 586,414 As of December 31, 2020, we were entitled to the following future contractual minimum lease payments (excluding operating expense reimbursements) on non-cancellable operating leases to be received which expire on various dates through 2038 (amounts in thousands): 2021 $ 492,574 2022 489,185 2023 468,877 2024 431,204 2025 391,228 Thereafter 1,846,423 $ 4,119,491 The above future minimum lease payments exclude tenant recoveries, amortization of deferred rent receivables and the net accretion of above-below-market lease intangibles. Some leases are subject to termination options generally upon payment of a termination fee. The preceding table is prepared assuming such options are not exercised. Lessee We determine if an arrangement is a lease at inception. Our operating lease agreements relate to three ground lease assets and are reflected in right-of-use assets of $29.1 million and lease liabilities of $29.1 million in our consolidated balance sheet as of December 31, 2020. Right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Right-of-use assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. Variable lease payments are excluded from the right-of-use assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred. We make payments under ground leases related to three of our properties. The ground leases are due to expire between the years 2050 and 2077, inclusive of extension options, and have no variable payments or residual value guarantees. As our leases do not provide an implicit rate, we determined our incremental borrowing rate based on information available at the date of adoption of ASU No. 2016-02, Leases (Topic 842), in determining the present value of lease payments. The weighted average incremental borrowing rate used to calculate the right-of-use assets and lease liabilities as of December 31, 2020 was 4.5%. Rent expense for lease payments related to our operating leases is recognized on a straight-line basis over the non-cancellable term of the leases. The weighted average remaining lease term as of December 31, 2020 was 49.3 years. As of December 31, 2020, the following table summarizes our future minimum lease payments with the amounts discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): 2021 $ 1,518 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted lease payments 72,852 Present value discount (43,748) Ground lease liabilities $ 29,104
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one Rental revenue includes fixed and variable payments. Fixed payments primarily relate to base rent and variable payments primarily relate to tenant expense reimbursements for certain property operating costs. The components of rental revenue for the year ended December 31, 2020 and 2019 are as follows (amounts in thousands): Year Ended December 31, 2020 2019 Fixed payments $ 496,515 $ 510,799 Variable payments 66,556 75,615 Total rental revenue $ 563,071 $ 586,414 As of December 31, 2020, we were entitled to the following future contractual minimum lease payments (excluding operating expense reimbursements) on non-cancellable operating leases to be received which expire on various dates through 2038 (amounts in thousands): 2021 $ 492,574 2022 489,185 2023 468,877 2024 431,204 2025 391,228 Thereafter 1,846,423 $ 4,119,491 The above future minimum lease payments exclude tenant recoveries, amortization of deferred rent receivables and the net accretion of above-below-market lease intangibles. Some leases are subject to termination options generally upon payment of a termination fee. The preceding table is prepared assuming such options are not exercised. Lessee We determine if an arrangement is a lease at inception. Our operating lease agreements relate to three ground lease assets and are reflected in right-of-use assets of $29.1 million and lease liabilities of $29.1 million in our consolidated balance sheet as of December 31, 2020. Right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Right-of-use assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. Variable lease payments are excluded from the right-of-use assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred. We make payments under ground leases related to three of our properties. The ground leases are due to expire between the years 2050 and 2077, inclusive of extension options, and have no variable payments or residual value guarantees. As our leases do not provide an implicit rate, we determined our incremental borrowing rate based on information available at the date of adoption of ASU No. 2016-02, Leases (Topic 842), in determining the present value of lease payments. The weighted average incremental borrowing rate used to calculate the right-of-use assets and lease liabilities as of December 31, 2020 was 4.5%. Rent expense for lease payments related to our operating leases is recognized on a straight-line basis over the non-cancellable term of the leases. The weighted average remaining lease term as of December 31, 2020 was 49.3 years. As of December 31, 2020, the following table summarizes our future minimum lease payments with the amounts discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): 2021 $ 1,518 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted lease payments 72,852 Present value discount (43,748) Ground lease liabilities $ 29,104

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings Litigation Except as described below, as of December 31, 2020, we were not involved in any material litigation, nor, to our knowledge, was any material litigation threatened against us or our properties, other than routine litigation arising in the ordinary course of business such as disputes with tenants. We believe that the costs and related liabilities, if any, which may result from such actions will not materially affect our consolidated financial position, operating results or liquidity. As previously disclosed, in October 2014, 12 former investors (the "Claimants") in Empire State Building Associates L.L.C. (“ESBA”), which prior to the initial public offering of our company (the "Offering"), owned the fee title to the Empire State Building, filed an arbitration with the American Arbitration Association against Peter L. Malkin, Anthony E. Malkin, Thomas N. Keltner, Jr., and our subsidiary ESRT MH Holdings LLC, the former supervisor of ESBA, (the "Respondents"). The statement of claim (also filed later in federal court in New York for the expressed purpose of tolling the statute of limitations) alleges breach of fiduciary duty and related claims in connection with the Offering and formation transactions and seeks monetary damages and declaratory relief. Claimants had opted out of a prior class action bringing similar claims that was settled with court approval. Respondents filed an answer and counterclaims. In March 2015, the federal court action was stayed on consent of all parties pending the arbitration. Arbitration hearings started in May 2016 and concluded in August 2018. On August 26, 2020, the arbitration panel issued an award that denied all Claimants’ claims with one exception, on which it awarded Claimants approximately $1.2 million, inclusive of seven years of interest through October 2, 2020. This amount was recorded as an IPO litigation expense in the consolidated statement of operations for the nine months ended September 30, 2020. Respondents believe that such award in favor of the Claimants is entirely without merit, and have sought vacatur of that portion of the award. In addition, certain of the Claimants have stated in the federal court action that they intend to pursue claims in that case against Respondents. Respondents believe that any such claims are meritless. Pursuant to indemnification agreements which were made with our directors, executive officers and chairman emeritus as part of our formation transactions, Anthony E. Malkin, Peter L. Malkin and Thomas N. Keltner, Jr. have defense and indemnity rights from us with respect to this arbitration. Unfunded Capital Expenditures At December 31, 2020, we estimate that we will incur approximately $121.9 million of capital expenditures (including tenant improvements and leasing commissions) on our properties pursuant to existing lease agreements. We expect to fund these capital expenditures with operating cash flow, additional property level mortgage financings, our unsecured credit facility, cash on hand and other borrowings. Future property acquisitions may require substantial capital investments for refurbishment and leasing costs. We expect that these financing requirements will be met in a similar fashion. Concentration of Credit Risk Financial instruments that subject us to credit risk consist primarily of cash and cash equivalents, restricted cash, short-term investments, tenant and other receivables and deferred rent receivables. At December 31, 2020, we held on deposit at various major financial institutions cash and cash equivalents and restricted cash balances in excess of amounts insured by the Federal Deposit Insurance Corporation . Real Estate Investments Our properties are located in Manhattan, New York; Fairfield County, Connecticut; and Westchester County, New York. The latter locations are suburbs of the city of New York. The ability of the tenants to honor the terms of their respective leases is dependent upon the economic, regulatory and social factors affecting the markets in which the tenants operate. We perform ongoing credit evaluations of our tenants for potential credit losses. Tenant Credit Evaluations Our investments in real estate properties are subject to risks incidental to the ownership and operation of commercial real estate. These risks include, among others, the risks normally associated with changes in general economic conditions, trends in the real estate industry, creditworthiness of tenants, competition of tenants and customers, changes in tax laws, interest rate levels, the availability and cost of financing, and potential liability under environmental and other laws. We may require tenants to provide some form of credit support such as corporate guarantees and/or other financial guarantees and we perform ongoing credit evaluations of tenants. Although the tenants operate in a variety of industries, to the extent we have a significant concentration of rental revenue from any single tenant, the inability of that tenant to make its lease payments could have an adverse effect on our company. Major Customers and Other Concentrations For the year ended December 31, 2020, other than two tenants who accounted for 6.9% and 3.5% of rental revenues, no other tenant in our portfolio accounted for more than 2.0% of rental revenues. For the year ended December 31, 2019, other than three tenants who accounted for 6.8%, 3.2% and 3.2% of rental revenues, no other tenant in our portfolio accounted for more than 2.0% of rental revenues. For the year ended December 31, 2018, other than five tenants who accounted for 6.0%, 3.1%, 2.9%, 2.0% and 2.0% of rental revenues, no other tenant in our portfolio accounted for more than 2.0% of rental revenues. For the years ended December 31, 2020, 2019 and 2018, the six properties listed below accounted for the indicated percentage of total rental revenues. No other property accounted for more than 5.0% of total rental revenues. Year Ended December 31, 2020 2019 2018 Empire State Building 32.8 % 32.9 % 31.9 % One Grand Central Place 12.4 % 12.3 % 12.8 % 111 West 33rd Street 10.5 % 9.9 % 9.3 % 1400 Broadway 8.0 % 7.1 % 7.1 % 250 West 57th Street 5.7 % 5.5 % 5.2 % First Stamford Place 5.4 % 5.4 % 5.9 % Asset Retirement Obligations We are required to accrue costs that we are legally obligated to incur on retirement of our properties which result from acquisition, construction, development and/or normal operation of such properties. Retirement includes sale, abandonment or disposal of a property. Under that standard, a conditional asset retirement obligation represents a legal obligation to perform an asset retirement activity in which the timing and/or method of settlement is conditional on a future event that may or may not be within a company’s control and a liability for a conditional asset retirement obligation must be recorded if the fair value of the obligation can be reasonably estimated. Environmental site assessments and investigations have identified asbestos or asbestos-containing building materials in certain of our properties. As of December 31, 2020, management has no plans to remove or alter these properties in a manner that would trigger federal and other applicable regulations for asbestos removal, and accordingly, the obligations to remove the asbestos or asbestos-containing building materials from these properties have indeterminable settlement dates. As such, we are unable to reasonably estimate the fair value of the associated conditional asset retirement obligation. However ongoing asbestos abatement, maintenance programs and other required documentation are carried out as required and related costs are expensed as incurred. Other Environmental Matters Certain of our properties have been inspected for soil contamination due to pollutants, which may have occurred prior to our ownership of these properties or subsequently in connection with its development and/or its use. Required remediation to such properties has been completed and, as of December 31, 2020, management believes that there are no obligations related to environmental remediation other than maintaining the affected sites in conformity with the relevant authority’s mandates and filing the required documents. All such maintenance costs are expensed as incurred. We expect that resolution of the environmental matters relating to the above will not have a material impact on our business, assets, consolidated and combined financial condition, results of operations or liquidity. However, we cannot be certain that we have identified all environmental liabilities at our properties, that all necessary remediation actions have been or will be undertaken at our properties or that we will be indemnified, in full or at all, in the event that such environmental liabilities arise. Insurance Coverage We carry insurance coverage on our properties of types and in amounts with deductibles that we believe are in line with coverage customarily obtained by owners of similar properties. Multiemployer Pension and Defined Contribution Plans We contribute to a number of multiemployer defined benefit pension plans under the terms of collective bargaining agreements that cover our union-represented employees. The risks of participating in these multiemployer plans are different from single-employer plans in the following respects: • Assets contributed to the multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. • If a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers. • If we choose to stop participating in some of our multiemployer plans, we may be required to pay those plans an amount based on the underfunded status of the plan, referred to as a withdrawal liability. We participate in various unions. The union in which we have significant employees and costs is 32BJ. 32BJ We participate in the Building Service 32BJ, ("Union"), Pension Plan and Health Plan. The Pension Plan is a multi-employer, non-contributory defined benefit pension plan that was established under the terms of collective bargaining agreements between the Service Employees International Union, Local 32BJ, the Realty Advisory Board on Labor Relations, Inc. and certain other employers. This Pension Plan is administered by a joint board of trustees consisting of union trustees and employer trustees and operates under employer identification number 13-1879376. The Pension Plan year runs from July 1 to June 30. Employers contribute to the Pension Plan at a fixed rate on behalf of each covered employee. Separate actuarial information regarding such pension plans is not made available to the contributing employers by the union administrators or trustees, since the plans do not maintain separate records for each reporting unit. However, on September 28, 2018, September 27, 2019 and September 28, 2020, the actuary certified that for the plan years beginning July 1, 2018, July 1, 2019 and July 1, 2020, respectively, the Pension Plan was in critical status under the Pension Protection Act of 2006. The Pension Plan trustees adopted a rehabilitation plan consistent with this requirement. For each of the years ended June 30, 2020, 2019 and 2018, the Pension Plan received contributions from employers totaling $291.3 million, $290.1 million and $272.3 million, respectively. The Health Plan was established under the terms of collective bargaining agreements between the Union, the Realty Advisory Board on Labor Relations, Inc. and certain other employers. The Health Plan provides health and other benefits to eligible participants employed in the building service industry who are covered under collective bargaining agreements, or other written agreements, with the Union. The Health Plan is administered by a Board of Trustees with equal representation by the employers and the Union and operates under employer identification number 13-2928869. The Health Plan receives contributions in accordance with collective bargaining agreements or participation agreements. Generally, these agreements provide that the employers contribute to the Health Plan at a fixed rate on behalf of each covered employee. For the years ended June 30, 2020, 2019 and 2018, the Health Plan received contributions from employers totaling $1.6 billion, $1.5 billion and $1.4 billion, respectively. Term of Collective Bargaining Agreement The most recent collective bargaining agreement for Local 32BJ commenced from January 1, 2020 and runs through December 31, 2023. Contributions Contributions we made to the multi-employer plans for the years ended December 31, 2020, 2019 and 2018 are included in the table below (amounts in thousands): For the Year Ended December 31, Benefit Plan 2020 2019 2018 Pension Plans (pension and annuity)* $ 2,383 $ 3,418 $ 3,327 Health Plans** 6,873 10,055 9,373 Other*** 416 641 814 Total plan contributions $ 9,672 $ 14,114 $ 13,514 * Pension plans include $0.8 million, $1.0 million and $1.0 million for the years ended 2020, 2019 and 2018, respectively, to multiemployer plans not discussed above. ** Health plans include $1.4 million, $1.8 million and $1.6 million for the years ended 2020, 2019 and 2018, respectively, to multiemployer plans not discussed above. *** Other consists of union costs which were not itemized between pension and health plans. Other includes $0.3 million, $0.4 million and $0.2 million for the years ended 2020, 2019 and 2018, respectively, in connection with other multiemployer plans not discussed above.

Capital

Capital	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Capital	Capital Shares and Units As of December 31, 2020, there were approximately 285.3 million operating partnership units outstanding, of which approximately 171.6 million, or 60.1%, were owned by ESRT and approximately 113.7 million, or 39.9%, were owned by other partners, including ESRT directors, members of senior management and other employees. On May 16, 2019, the Empire State Realty Trust, Inc. Empire State Realty OP, L.P. 2019 Equity Incentive Plan (“2019 Plan”) was approved by our shareholders. The 2019 Plan provides for grants to directors, employees and consultants of our company and operating partnership, including options, restricted stock, restricted stock units, stock appreciation rights, performance awards, dividend equivalents and other equity-based awards. An aggregate of approximately 11.0 million shares of our common stock are authorized for issuance under awards granted pursuant to the 2019 Plan. We will not issue any new equity awards under the First Amended and Restated Empire State Realty Trust, Inc. and Empire State Realty OP, L.P. 2013 Equity Incentive Plan ("2013 Plan", and collectively with the 2019 Plan, "the Plans"). The shares of ESRT Class A common stock underlying any awards under the 2019 Plan and the 2013 Plan that are forfeited, canceled or otherwise terminated, other than by exercise, will be added back to the shares of ESRT Class A common stock available for issuance under the 2019 Plan. Shares tendered or held back upon exercise of a stock option or settlement of an award under the 2019 Plan or the 2013 Plan to cover the exercise price or tax withholding and shares subject to a stock appreciation right that are not issued in connection with the stock settlement of the stock appreciation right upon exercise thereof, will not be added back to the shares of ESRT Class A common stock available for issuance under the 2019 Plan. In addition, shares of ESRT Class A common stock repurchased on the open market will not be added back to the shares of ESRT Class A common stock available for issuance under the 2019 Plan. Long-term incentive plan ("LTIP") units are a special class of partnership interests. Each LTIP unit awarded will be deemed equivalent to an award of one share of ESRT stock under the Plans, reducing the availability for other equity awards on a one-for-one basis. The vesting period for LTIP units, if any, will be determined at the time of issuance. Under the terms of the LTIP units, we will revalue for tax purposes its assets upon the occurrence of certain specified events, and any increase in valuation from the time of grant until such event will be allocated first to the holders of LTIP units to equalize the capital accounts of such holders with the capital accounts of unitholders. Subject to any agreed upon exceptions, once vested and having achieved parity with unitholders, LTIP units are convertible into operating partnership units on a one-for-one basis. LTIP units subject to time-based vesting, whether vested or not, receive the same per unit distributions as OP Units, which equal per share dividends (both regular and special) on our common stock. Performance based LTIP units receive 10% of such distributions currently, unless and until such LTIP units are earned based on performance, at which time they will receive the accrued and unpaid 90% and will commence receiving 100% of such distributions thereafter. Stock and Publicly Traded Operating Partnership Unit Repurchase Program On December 31, 2019 our board authorized the repurchase of up to $500 million of our Class A common stock and the Operating Partnership’s Series ES, Series 250 and Series 60 operating partnership units from January 1, 2020 through December 31, 2020. On December 11, 2020, our board approved a new authorization for the repurchase of up to $500 million of such securities from January 1, 2021 through December 31, 2021. Under the repurchase program, we may purchase our Class A common stock and the Operating Partnership’s Series ES, Series 250 and Series 60 operating partnership units in accordance with applicable securities laws from time to time in the open market or in privately negotiated transactions. The timing, manner, price and amount of any repurchases will be determined by us at our discretion and will be subject to stock price, availability, trading volume and general market conditions. The authorization does not obligate us to acquire any particular amount of securities, and the program may be suspended or discontinued at our discretion without prior notice. The following table summarizes our purchases of equity securities for the year ended December 31, 2020: Period Total Number of Shares Purchased Average Price Paid Per Share Total Number of Shares Purchased as Part of Publicly Announced Plan Maximum Approximate Dollar Value Available for Future Purchase (in thousands) Year ended December 31, 2020 17,279,252 $ 8.32 17,279,252 $ 356,287 Private Perpetual Preferred Units As of December 31, 2020, there were 4,664,038 Series 2019 Preferred Units ("Series 2019 Preferred Units") and 1,560,360 Series 2014 Private Perpetual Preferred Units ("Series 2014 Preferred Units"). The Series 2019 Preferred Units have a liquidation preference of $13.52 per unit and are entitled to receive cumulative preferential annual cash distributions of $0.70 per unit payable in arrears on a quarterly basis. The Series 2019 Preferred Units are not redeemable at the option of the holders and are redeemable at our option only in the case of specific defined events. The Series 2014 Preferred Units which have a liquidation preference of $16.62 per unit and are entitled to receive cumulative preferential annual cash distributions of $0.60 per unit payable in arrears on a quarterly basis. The Series 2014 Preferred Units are not redeemable at the option of the holders and are redeemable at our option only in the case of specific defined events. Distributions The following table summarizes the distributions paid on our operating partnership units for the years ended December 31, 2020, 2019 and 2018: Record Date Payment Date Amount per Operating Partnership Unit June 19, 2020 June 30, 2020 $0.105 March 16, 2020 March 31, 2020 $0.105 December 23, 2019 December 31, 2019 $0.105 September 16, 2019 September 30, 2019 $0.105 June 14, 2019 June 28, 2019 $0.105 March 15, 2019 March 29, 2019 $0.105 December 17, 2018 December 31, 2018 $0.105 September 14, 2018 September 28, 2018 $0.105 June 15, 2018 June 29, 2018 $0.105 March 15, 2018 March 30, 2018 $0.105 We paid a dividend in the first and second quarters of 2020 and suspended the dividend for the third and fourth quarters of 2020. Total distributions paid to OP unitholders and Preferred unitholders during 2020, 2019 and 2018 totaled $65.0 million, $127.8 million and $126.5 million, respectively. Incentive and Share-Based Compensation The Plans provide for grants to directors, employees and consultants consisting of stock options, restricted stock, dividend equivalents, stock payments, performance shares, LTIP units, stock appreciation rights and other incentive awards. An aggregate of 11.0 million shares of ESRT common stock are authorized for issuance under awards granted pursuant to the 2019 Plan, and as of December 31, 2020, approximately 8.5 million shares of ESRT common stock remain available for future issuance under the Plans. In December and August 2020, we granted Grant H. Hill and R. Paige Hood, respectively, our new non-employee directors, a total of 31,117 LTIP units that are subject to time-based vesting with a fair market value of $0.2 million. These awards vest ratably on each of the first three anniversaries of May 15, 2020, subject generally to their continued service on our Board of Directors. In May 2020, we made grants of LTIP units under the 2019 Plan. At such time, we granted our non-employee directors a total of 171,153 LTIP units that are subject to time-based vesting with fair market values of $1.1 million. These awards vest ratably over three years from the date of the grant, subject generally to the director's continued service on our Board of Directors. We also granted Christina Chiu, our Executive Vice President and Chief Financial Officer, a total of 82,199 LTIP units that are subject to time-based vesting and 116,927 LTIP units that are subject to market-based vesting, with fair market values of $0.5 million for the time-based vesting awards and $0.5 million for the market-based vesting awards. We also granted certain other employees a total of 63,229 LTIP units that are subject to time-based vesting with a fair market value of $0.4 million. The awards subject to time-based vesting vest ratably over three In March 2020, we made grants of LTIP units to executive officers under the 2019 Plan. At such time, we granted to executive officers a total of 745,155 LTIP units that are subject to time-based vesting and 3,358,767 LTIP units that are subject to market-based vesting, with fair market values of $5.6 million for the time-based vesting awards and $14.0 million for the 22 market-based vesting awards. In March 2020, we made grants of LTIP units and restricted stock to certain other employees under the 2019 Plan. At such time, we granted to certain other employees a total of 113,971 LTIP units and 158,806 shares of restricted stock that are subject to time-based vesting and 502,475 LTIP units that are subject to market-based vesting, with fair market values of $2.3 million for the time-based vesting awards and $2.3 million for the market-based vesting awards. The awards subject to time-based vesting vest ratably over four years from January 1, 2020, subject generally to the grantee's continued employment. The first installment vests on January 1, 2021 and the remainder will vest thereafter in three equal annual installments. The vesting of the LTIP units subject to market-based vesting is based on the achievement of relative total stockholder return hurdles over a three-year performance period, commencing on January 1, 2020. Following the completion of the three-year performance period, our Compensation and Human Capital Committee will determine the number of LTIP units to which the grantee is entitled based on our performance relative to the performance hurdles set forth in the LTIP unit award agreements the grantee entered into in connection with the award grant. These units then vest in two installments, with the first installment vesting on January 1, 2023 and the second installment vesting on January 1, 2024, subject generally to the grantee's continued employment on those dates. For awards granted in 2017, 2018, 2019 and 2020, our named executive officers could elect to receive their annual incentive bonus in any combination of (i) cash or vested LTIP's at the face amount of such bonus or (ii) time-vesting LTIP's which would vest over three years, subject to continued employment, at 125% of such face amount (the "bonus election program"). In March 2020, we made grants of LTIP units to executive officers under the 2019 Plan in connection with the 2019 bonus election program. We granted to executive officers a total of 624,380 LTIP units that are subject to time-based vesting with a fair market value of $4.4 million. Of these LTIP units, 23,049 LTIP units vested immediately on the grant date and 601,331 LTIP units vest ratably over three years from January 1, 2020, subject generally to the grantee's continued employment. The first installment vests on January 1, 2021 and the remainder will vest thereafter in two equal annual installments. In COVID-19 disrupted markets during the first quarter of 2020, the LTIP units that are subject to market-based vesting were undervalued on initial appraisal, and the resulting number of LTIP units issued in March 2020 was reduced on final appraisal to match the original board-approved dollar value. In June 2020, we reduced the grants of LTIP units that are subject to market-based vesting which were awarded to executive officers and certain other employees by 666,933 LTIP units with fair market values of $2.8 million and 99,630 LTIP units with fair market values of $0.5 million, respectively. In October and May 2019, we made grants of LTIP units to our non-employee directors under the 2019 Plan. At such times, we granted a total of 76,718 LTIP units that are subject to time-based vesting with fair market values of $1.1 million. The awards vest ratably over three years from the date of the grant, subject generally to the director's continued service on our Board of Directors. In March 2019, we made grants of LTIP units to executive officers under the 2013 Plan. At such time, we granted to executive officers a total of 461,693 LTIP units that are subject to time-based vesting and 1,806,520 LTIP units that are subject to market-based vesting, with fair market values of $6.4 million for the time-based vesting awards and $12.8 million for the market-based vesting awards. In March 2019 we made grants of LTIP units and restricted stock to certain other employees under the 2013 Plan. At such time, we granted to certain other employees a total of 61,432 LTIP units and 69,358 shares of restricted stock that are subject to time-based vesting and 113,383 LTIP units that are subject to market-based vesting, with fair market values of $2.0 million for the time-based vesting awards and $0.9 million for the market-based vesting awards. The awards subject to time-based vesting vest ratably over four years from January 1, 2019, subject generally to the grantee's continued employment. The first installment vests on January 1, 2020 and the remainder will vest thereafter in three equal annual installments. The vesting of the LTIP units subject to market-based vesting is based on the achievement of relative total stockholder return hurdles over a three-year performance period, commencing on January 1, 2019. Following the completion of the three-year performance period, our compensation committee will determine the number of LTIP units to which the grantee is entitled based on our performance relative to the performance hurdles set forth in the LTIP unit award agreements the grantee entered into in connection with the award grant. These units then vest in two installments, with the first installment vesting on January 1, 2022 and the second installment vesting on January 1, 2023, subject generally to the grantee's continued employment on those dates. In March 2019, we made grants of LTIP units to executive officers under the 2013 Plan in connection with the 2018 bonus election program. We granted to executive officers a total of 334,952 LTIP units that are subject to time-based vesting with a fair market value of $4.6 million. Of these LTIP units, 26,056 LTIP units vested immediately on the grant date and 308,896 LTIP units vest ratably over three years from January 1, 2019, subject generally to the grantee's continued employment. The first installment vests on January 1, 2020 and the remainder will vest thereafter in two equal annual installments. Share-based compensation for time-based equity awards is measured at the fair value of the award on the date of grant and recognized as an expense on a straight-line basis over the shorter of (i) the stated vesting period, which is generally three three For the market-based LTIP units, the fair value of the awards was estimated using a Monte Carlo Simulation model. Our stock price, along with the prices of the comparative indexes, is assumed to follow the Geometric Brownian Motion Process. Geometric Brownian motion is a common assumption when modeling in financial markets, as it allows the modeled quantity (in this case, the stock price) to vary randomly from its current value and take any value greater than zero. The volatilities of the returns on our stock price and the comparative indexes were estimated based on implied volatilities and historical volatilities using a six-year look-back period. The expected growth rate of the stock prices over the performance period is determined with consideration of the risk free rate as of the grant date. For LTIP unit awards that are time-based, the fair value of the awards was estimated based on the fair value of our stock at the grant date discounted for the restriction period during which the LTIP units cannot be redeemed or transferred and the uncertainty regarding if, and when, the book capital account of the LTIP units will equal that of the common units. For restricted stock awards that are time-based, we estimate the stock compensation expense based on the fair value of the stock at the grant date. LTIP units and ESRT restricted stock issued during the year ended December 31, 2020, 2019 and 2018 were valued at $28.3 million, $27.9 million and $23.6 million, respectively. The weighted-average per unit or share fair value was $5.44, $9.56 and $8.54 for grants issued in 2020, 2019 and 2018, respectively. The per unit or share granted in 2020 was estimated on the respective dates of grant using the following assumptions: an expected life from 2.0 to 5.5 years, a dividend rate of 3.70%, a risk-free interest rate from 0.16% to 0.50%, and an expected price volatility from 19.0% to 26.0%. The per unit or share granted in 2019 was estimated on the respective dates of grant using the following assumptions: an expected life from 2.0 to 5.3 years, a dividend rate of 2.40%, a risk-free interest rate from 2.48% to 2.63%, and an expected price volatility from 17.0% to 22.0%. The per unit or share granted in 2018 was estimated on the respective dates of grant using the following assumptions: an expected life of 2.8 years, a dividend rate of 2.30%, a risk-free interest rate of 2.50% and an expected price volatility of 20.0%. No other stock options, dividend equivalents, or stock appreciation rights were issued or outstanding in 2020, 2019 and 2018. The following is a summary of ESRT restricted stock and LTIP unit activity for the year ended December 31, 2020: ESRT Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2019 118,918 5,986,569 $ 9.73 Vested (58,326) (1,052,692) 14.04 Granted 161,449 5,042,810 5.44 Forfeited or unearned (4,341) (2,226,403) 7.55 Unvested balance at December 31, 2020 217,700 7,750,284 $ 6.94 The total fair value of LTIP units and restricted stock that vested during 2020, 2019 and 2018 was $15.6 million, $10.1 million and $7.7 million, respectively. The LTIP unit and ESRT restricted stock award agreements will immediately vest when a grantee attains the (i) age of 60 or 65, as applicable, and (ii) the date on which the grantee has first completed ten years of continuous service with our company or its affiliates. For award agreements that qualify, we recognize noncash compensation expense on the grant date for the time-based awards and ratably over the vesting period for the market-based awards, and accordingly, we recognized $2.6 million, $2.0 million and $1.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. Unrecognized compensation expense was $1.4 million at December 31, 2020, which will be recognized over a weighted average period of 2.1 years. For the remainder of the LTIP unit and ESRT restricted stock awards, we recognize noncash compensation expense ratably over the vesting period, and accordingly, we recognized $22.9 million, $18.8 million and $17.0 million in noncash compensation expense for the years ended December 31, 2020, 2019 and 2018, respectively. Unrecognized compensation expense was $26.5 million at December 31, 2020, which will be recognized over a weighted average period of 2.2 years. Earnings Per Unit Earnings per unit for the years ended December 31, 2020, 2019 and 2018 is computed as follows (amounts in thousands, except per share amounts): For the Year Ended December 31, 2020 2019 2018 Numerator: Net income (loss) $ (22,889) $ 84,290 $ 117,253 Private perpetual preferred unit distributions (4,197) (1,743) (936) Earnings allocated to unvested shares (985) (885) (851) Net income (loss) attributable to common unitholders - basic and diluted $ (28,071) $ 81,662 $ 115,466 Denominator: Weighted average units outstanding - basic 283,826 297,798 297,258 Effect of dilutive securities: Stock-based compensation plans 11 — 1 Weighted average shares outstanding - diluted 283,837 297,798 297,259 Earnings per unit - basic and diluted $ (0.10) $ 0.27 $ 0.39

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Tax Protection Agreements In 2013, we and ESRT entered into a tax protection agreement with Anthony E. Malkin and Peter L. Malkin that is intended to protect to a limited extent the Malkin Group and an additional third party investor in Metro Center (who was one of the original landowners and was involved in the development of the property) against certain tax consequences arising from a transaction involving one of four properties, which we refer to in this section as the protected assets. First, this agreement provides that our operating partnership will not sell, exchange, transfer or otherwise dispose of such protected assets, or any interest in a protected asset, until (i) October 7, 2025, with respect to one protected asset, First Stamford Place, and (ii) the later of (x) October 7, 2021 and (y) the death of both Peter L. Malkin and Isabel W. Malkin, who are 87 and 84 years old, respectively, for the three other protected assets, Metro Center, 10 Bank Street and 1542 Third Avenue, unless: (1) Anthony E. Malkin consents to the sale, exchange, transfer or other disposition; or (2) we deliver to each protected party thereunder a cash payment intended to approximate the tax liability arising from the recognition of the pre-contribution built-in gain resulting from the sale, exchange, transfer or other disposition of such protected asset (with the pre-contribution “built-in gain” being not more than the taxable gain that would have been recognized by such protected party if the protected asset been sold for fair market value in a taxable transaction at the time of the consolidation) plus an additional amount so that, after the payment of all taxes on amounts received pursuant to the agreement (including any tax liability incurred as a result of receiving such payment), the protected party retains an amount equal to such protected party’s total tax liability incurred as a result of the recognition of the pre-contribution built-in gain pursuant to such sale, exchange, transfer or other disposition; or (3) the disposition does not result in a recognition of any built-in gain by the protected party. Second, with respect to the Malkin Group, including Anthony E. Malkin and Peter L. Malkin, and one additional third party investor in Metro Center (who was one of the original landowners and was involved in the development of the property), to protect against gain recognition resulting from a reduction in such continuing investor’s share of the operating partnership liabilities, the agreement provides that during the period from October 7, 2013 until such continuing investor owns less than the aggregate number of operating partnership units and shares of ESRT common stock equal to 50% of the aggregate number of such units and shares such investor received in the formation transactions, which we refer to in this section as the tax protection period, we will (i) refrain from prepaying any amounts outstanding under any indebtedness secured by the protected assets and (ii) use our commercially reasonable efforts to refinance such indebtedness at or prior to maturity at its current principal amount, or, if we are unable to refinance such indebtedness at its current principal amount, at the highest principal amount possible. The agreement also provides that, during the tax protection period, we will make available to such continuing investors the opportunity (i) to enter into a “bottom dollar” guarantee of their allocable share of $160.0 million of our aggregate indebtedness meeting certain requirements or (ii) in the event we have recourse debt outstanding and such a continuing investor agrees, in lieu of guaranteeing debt pursuant to clause (i) above, to enter into a deficit restoration obligation, in each case, in a manner intended to provide an allocation of our liabilities to the continuing investor. In the event that a continuing investor guarantees our debt, such continuing investor will be responsible, under certain circumstances, for the repayment of the guaranteed amount to the lender in the event that the lender would otherwise recognize a loss on the loan, such as, for example, if property securing the loan was foreclosed and the value was not sufficient to repay a certain amount of the debt. A deficit restoration obligation is a continuing investor’s obligation, under certain circumstances, to contribute a designated amount of capital to us upon our liquidation in the event that our assets are insufficient to repay our liabilities. Because we expect that we will at all times have sufficient liabilities to allow us to meet our obligations to allocate liabilities to our partners that are protected parties under the tax protection agreement, our indemnification obligation with respect to “certain tax liabilities” would generally arise only in the event that we dispose in a taxable transaction of a protected asset within the period specified above in a taxable transaction. In the event of such a disposition, the amount of our indemnification obligation would depend on several factors, including the amount of “built-in gain,” if any, recognized and allocated to the indemnified partners with respect to such disposition and the effective tax rate to be applied to such gain at the time of such disposition. Our partnership agreement requires that allocations with respect to such acquired property be made in a manner consistent with Section 704(c) of the Code. Treasury Regulations issued under Section 704(c) of the Code provide partnerships with a choice of several methods of allocating book-tax differences. Under the tax protection agreement, we have agreed to use the “traditional method” for accounting for book-tax differences for the properties acquired by us in the consolidation. Under the traditional method, which is the least favorable method from our perspective, the carryover basis of the acquired properties in our hands (i) may cause us to be allocated lower amounts of depreciation and other deductions for tax purposes than would be allocated to us if all of the acquired properties were to have a tax basis equal to their fair market value at the time of acquisition and (ii) in the event of a sale of such properties, could cause us to be allocated gain in excess of its corresponding economic or book gain (or taxable loss that is less than its economic or book loss), with a corresponding benefit to the partners transferring such properties to us for interests in us. In 2016, we entered into a tax protection agreement with Q REIT Holding LLC, a Qatar Financial Centre limited liability company and a wholly owned subsidiary of the Qatar Investment Authority, a governmental authority of the State of Qatar ("QREIT", and together with any eligible transferee, "QIA"). Subject to certain minimum thresholds and conditions, ESRT will indemnify QIA for certain applicable U.S. federal and state taxes payable by QIA in connection with dividends paid by ESRT on the QIA shares that are attributable to capital gains from the sale or exchange of any U.S. real property interests. ESRT's obligation to indemnify QIA will terminate one year following the date on which the sum of the QIA shares then owned by QIA falls below 10% of ESRT outstanding common shares. Registration Rights We entered into a registration rights agreement with certain persons receiving shares of ESRT common stock or operating partnership units in the formation transactions, including certain members of ESRT's senior management team and our other continuing investors. In connection therewith, we have filed, and are obligated to maintain the effectiveness of, an automatically effective shelf registration statement, along with a prospectus supplement, with respect to, among other things, shares of ESRT Class A common stock that may be issued upon redemption of operating partnership units or issued upon conversion of shares of ESRT Class B common stock to continuing investors in the public existing entities. Pursuant to the registration rights agreement, under certain circumstances, ESRT will also be required to undertake an underwritten offering upon the written request of the Malkin Group, which we refer to as the holder, provided (i) the registrable shares to be registered in such offering will have a market value of at least $150.0 million, (ii) ESRT will not be obligated to effect more than two underwritten offerings during any 12-month period; and (iii) the holder will not have the ability to effect more than four underwritten offerings. In addition, if ESRT files a registration statement with respect to an underwritten offering for its own account or on behalf of the holder, the holder will have the right, subject to certain limitations, to register such number of registrable shares held by him, her or it as each such holder requests. With respect to underwritten offerings on behalf of the holder, ESRT will have the right to register such number of primary shares as it requests; provided, however, that if cut backs are required by the managing underwriters of such an offering, ESRT's primary shares shall be cutback first (but in no event will our shares be cut back to less than $25.0 million). ESRT has also agreed to indemnify the persons receiving rights against specified liabilities, including certain potential liabilities arising under the Securities Act, or to contribute to the payments such persons may be required to make in respect thereof. ESRT has agreed to pay all of the expenses relating to the registration and any underwritten offerings of such securities, including, without limitation, all registration, listing, filing and stock exchange or FINRA fees, all fees and expenses of complying with securities or “blue sky” laws, all printing expenses and all fees and disbursements of counsel and independent public accountants retained by ESRT, but excluding underwriting discounts and commissions, any out-of-pocket expenses (except ESRT will pay any holder’s out-of-pocket fees (including disbursements of such holder’s counsel, accountants and other advisors) up to $25,000 in the aggregate for each underwritten offering and each filing of a resale shelf registration statement or demand registration statement), and any transfer taxes. Employment Agreement and Change in Control Severance Agreements ESRT entered into an employment agreement with Anthony E. Malkin, which provides for salary, bonuses and other benefits, including among other things, severance benefits upon a termination of employment under certain circumstances and the issuance of equity awards. In addition, ESRT entered into change in control severance agreements with Thomas P. Durels, Thomas N. Keltner, Jr. and Christina Chiu. Indemnification of Our Directors and Officers We entered into indemnification agreements with each of ESRT's directors, executive officers, chairman emeritus and certain other parties, providing for the indemnification by us for certain liabilities and expenses incurred as a result of actions brought, or threatened to be brought, against (i) ESRT's directors, executive officers and chairman emeritus and (ii) ESRT's executive officers, chairman emeritus and certain other parties who are former members, managers, securityholders, directors, limited partners, general partners, officers or controlling persons of our predecessor in such capacities. Excluded Properties and Businesses The Malkin Group, including Anthony E. Malkin, our Chairman and Chief Executive Officer, owns non-controlling interests in, and Anthony E. Malkin and Peter L. Malkin control the general partners or managers of, the entities that own interests in nine multi-family properties and five net leased retail properties, (including one single tenant retail property in Greenwich, Connecticut). The Malkin Group also owns non-controlling interests in one Manhattan office property, two Manhattan retail properties and several retail properties outside of Manhattan, none of which were contributed to us in the formation transactions. We refer to the non-controlling interests described above collectively as the excluded properties. In addition, the Malkin Group owns interests in one mezzanine and senior equity fund and five property managers, and which we refer to collectively as the excluded businesses. Other than the Greenwich retail property, we do not believe that the excluded properties or the excluded businesses are consistent with our portfolio geographic or property type composition, management or strategic direction. Pursuant to management and/or service agreements with the owners of interests in those excluded properties and services agreements with five residential property managers and the managers of certain other excluded businesses which historically were managed by affiliates of our predecessor, we are designated as the asset manager (supervisor) and/or property manager of the excluded properties and will provide services to the owners of certain of the excluded properties and the five residential property managers and provide services and access to office space to the existing managers of the other excluded businesses. As the manager or service provider, we are paid a management or other fee with respect to those excluded properties and excluded businesses where our predecessor had previously received a management fee on the same terms as the fee paid to our predecessor, and reimbursed for our costs in providing the management and other services to those excluded properties and businesses where our predecessor had not previously received a management fee. ESRT's management of the excluded properties and provision of services to the five residential property managers and the existing managers of the other excluded businesses represent a minimal portion of our overall business. There is no established time period in which we will manage such properties or provide services to the owners of certain of the excluded properties and the five residential property managers and provide services and access to office space to the existing managers of the other excluded businesses; and Peter L. Malkin and Anthony E. Malkin expect to sell certain properties or unwind these businesses over time. We are not precluded from acquiring all or certain interests in the excluded properties or businesses. If we were to attempt any such acquisition, we anticipate that Anthony E. Malkin, ESRT's Chairman and Chief Executive Officer, will not participate in the negotiation process on our behalf with respect to our potential acquisition of any of these excluded properties or businesses, and the approval of a majority of ESRT's independent directors will be required to approve any such acquisition. Services are and were provided by us to excluded properties and businesses. These transactions are reflected in our consolidated statements of operations as third-party management and other fees. We earned asset management (supervisory) and service fees from excluded properties and businesses of $0.9 million, $0.9 million and $1.1 million during the years ended December 31, 2020, 2019 and 2018, respectively. We earned property management fees from excluded properties of $0.3 million, $0.3 million and $0.3 million during the years ended December 31, 2020, 2019 and 2018, respectively. Other

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes TRS Holdings and Observatory TRS are taxable entities and their consolidated provision for income taxes consisted of the following for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): For the Year Ended December 31, 2020 2019 2018 Current: Federal $ 4,932 $ (1,077) $ (2,389) State and local 2,699 (872) (2,253) Total current 7,631 (1,949) (4,642) Deferred: Federal (340) (248) — State and local (320) (232) — Total deferred (660) (480) — Income tax benefit (expense) $ 6,971 $ (2,429) $ (4,642) In December 2017, the Tax Cuts and Jobs Act (the “TCJA”) was enacted. The TCJA includes a number of changes to existing U.S. tax laws, most notably a reduction of the U.S. corporate income tax rate from 35 percent to 21 percent, effective January 1, 2018. In March 2020, the Coronavirus Aid, Relief, Economic Security (“CARES”) Act was enacted. The CARES Act includes a number of federal tax reliefs, including the carryback of a net operating loss (“NOL”) incurred in 2018, 2019 and 2020 to each of the five preceding taxable years to generate a refund of previous paid income taxes. Such NOLs may offset 100% of taxable income for taxable years beginning before 2021 (80% thereafter). Many states, including New York, have not adopted the NOL provisions of the CARES Act and continue to have their own rules with respect to the application of NOLs. The carryback of Observatory TRS’s NOL to previous tax years resulted in a 13% increase of U.S. corporation income tax benefit. As of December 31, 2020, our parent and general partner, Empire State Realty Trust, Inc., had $67.9 million of NOL carryforwards that may be used in the future to reduce the amount otherwise required to be distributed by ESRT to meet REIT requirements. However, for federal income tax purposes, the NOL will not be able to offset more than 80% of ESRT’s REIT taxable income and, therefore, may not be able to reduce the amount required to be distributed by ESRT to meet REIT requirements to zero, except for the tax year ended December 31, 2020, of which ESRT was able to offset 100% of its taxable income in accordance with the CARES Act. The federal NOL may be carried forward indefinitely. Other limitations may apply to ESRT’s ability to use its NOL to offset taxable income. As of December 31, 2020, the observatory TRS had a federal, state, and local income tax receivable of $8.1 million due to a NOL for the year ended December 31, 2020. Under special provisions of the CARES Act, the NOL can be carried back five years for federal income tax purposes. Due to limitations on the use of net operating loss carrybacks for state and local tax, the observatory TRS will carry forward $3.8 million of NOL to offset future taxable income, if any. The state and local NOL can be carried forward for up to 20 years. We measure deferred tax assets using enacted tax rates that will apply in the years in which the temporary differences are expected to be recovered or paid. The effective income tax rate is 47.0%, 34.0% and 34.0% for the years ended December 31, 2020, 2019 and 2018, respectively. The actual tax provision differed from that computed at the federal statutory corporate rate as follows (amounts in thousands): For the Year Ended December 31, 2020 2019 2018 Federal tax benefit (expense) at statutory rate $ 2,544 $ (1,575) $ (2,844) State income tax benefit (expense), net of federal benefit 2,379 (854) (1,798) Corporate income tax rate adjustment 2,048 — — Income tax benefit (expense) $ 6,971 $ (2,429) $ (4,642) The income tax effects of temporary differences that give rise to deferred tax assets are presented below as of December 31, 2020, 2019 and 2018 (amounts in thousands): 2020 2019 2018 Deferred tax assets: Deferred revenue on unredeemed observatory admission ticket sales $ 256 $ 916 $ 1,396 New York City net operating loss carryforward credit 334 — — Deferred tax assets $ 590 $ 916 $ 1,396 Deferred tax assets at December 31, 2020, 2019 and 2018, respectively, are attributable to the inclusion of deferred revenue on observatory admission ticket sales not redeemed at year-end in determining income for tax reporting purposes and are included in prepaid expenses and other assets on the consolidated balance sheets. The deferred tax assets at December 31, 2020, respectively, are attributable to the inclusion of the New York City net operating loss to be carried forward and utilized during income years for a period of 20 years. No valuation allowance has been recorded against the deferred tax asset because the company believes that the deferred tax asset will, more likely than not, be realized. This determination is based on the observatory TRS’s anticipated future taxable income and the reversal of the deferred tax asset. At December 31, 2020, 2019 and 2018, the TRS entities have no amount of unrecognized tax benefits. For tax years 2020, 2019, 2018 and 2017, the United States federal and state tax returns are open for examination.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We have identified two reportable segments: (1) Real Estate and (2) Observatory. Our real estate segment includes all activities related to the ownership, management, operation, acquisition, repositioning and disposition of our real estate assets. Our observatory segment operates the 86th and 102nd floor observatories at the Empire State Building. These two lines of businesses are managed separately because each business requires different support infrastructures, provides different services and has dissimilar economic characteristics such as investments needed, stream of revenues and different marketing strategies. We account for intersegment sales and rents as if the sales or rents were to third parties, that is, at current market prices. The following tables provide components of segment profit for each segment for the years ended December 31, 2020, 2019 and 2018, as reviewed by management (amounts in thousands): 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 563,071 $ — $ — $ 563,071 Intercompany rental revenue 17,827 — (17,827) — Observatory revenue — 29,057 — 29,057 Lease termination fees 9,416 — — 9,416 Third-party management and other fees 1,225 — — 1,225 Other revenue and fees 6,459 — — 6,459 Total revenues 597,998 29,057 (17,827) 609,228 Operating expenses: Property operating expenses 136,141 — — 136,141 Intercompany rent expense — 17,827 (17,827) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 62,244 — — 62,244 Observatory expenses — 23,723 — 23,723 Real estate taxes 121,923 — — 121,923 Impairment charges 6,204 — — 6,204 Depreciation and amortization 190,863 143 — 191,006 Total operating expenses 526,701 41,693 (17,827) 550,567 Total operating income (loss) 71,297 (12,636) — 58,661 Other income (expense): Interest income 2,542 95 — 2,637 Interest expense (89,907) — — (89,907) Loss on early extinguishment of debt (86) — — (86) IPO litigation expense (1,165) — — (1,165) Loss before income taxes (17,319) (12,541) — (29,860) Income tax (expense) benefit (843) 7,814 — 6,971 Net loss $ (18,162) $ (4,727) $ — $ (22,889) Segment assets $ 3,903,884 $ 246,811 $ — $ 4,150,695 Expenditures for segment assets $ 101,306 $ 2,754 $ — $ 104,060 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 586,414 $ — $ — $ 586,414 Intercompany rental revenue 82,469 — (82,469) — Observatory revenue — 128,769 — 128,769 Lease termination fees 4,352 — — 4,352 Third-party management and other fees 1,254 — — 1,254 Other revenue and fees 10,554 — — 10,554 Total revenues 685,043 128,769 (82,469) 731,343 Operating expenses: Property operating expenses 174,977 — — 174,977 Intercompany rent expense — 82,469 (82,469) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 61,063 — — 61,063 Observatory expenses — 33,767 — 33,767 Real estate taxes 115,916 — — 115,916 Depreciation and amortization 181,558 30 — 181,588 Total operating expenses 542,840 116,266 (82,469) 576,637 Total operating income 142,203 12,503 — 154,706 Other income (expense): Interest income 11,259 — — 11,259 Interest expense (79,246) — — (79,246) Income before income taxes 74,216 12,503 — 86,719 Income tax expense (896) (1,533) — (2,429) Net income $ 73,320 $ 10,970 $ — $ 84,290 Segment assets $ 3,671,211 $ 260,623 $ — $ 3,931,834 Expenditures for segment assets $ 191,630 $ 64,294 $ — $ 255,924 2018 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 493,231 $ — $ — $ 493,231 Intercompany rental revenue 79,954 — (79,954) — Tenant expense reimbursement 72,372 — — 72,372 Observatory revenue — 131,227 — 131,227 Lease termination fees 20,847 — — 20,847 Third-party management and other fees 1,440 — — 1,440 Other revenue and fees 12,394 — — 12,394 Total revenues 680,238 131,227 (79,954) 731,511 Operating expenses: Property operating expenses 167,379 — — 167,379 Intercompany rent expense — 79,954 (79,954) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 52,674 — — 52,674 Observatory expenses — 32,767 — 32,767 Real estate taxes 110,000 — — 110,000 Depreciation and amortization 168,430 78 — 168,508 Total operating expenses 507,809 112,799 (79,954) 540,654 Total operating income 172,429 18,428 — 190,857 Other income (expense): Interest income 10,661 — — 10,661 Interest expense (79,623) — — (79,623) Income before income taxes 103,467 18,428 — 121,895 Income tax expense (1,114) (3,528) — (4,642) Net income $ 102,353 $ 14,900 $ — $ 117,253 Segment assets $ 3,930,330 $ 265,450 $ — $ 4,195,780 Expenditures for segment assets $ 201,685 $ 54,811 $ — $ 256,496 During the second quarter 2020, we wrote-off $4.1 million of prior expenditures on a potential energy efficiency project in our real estate segment that is not economically feasible in today's regulatory environment. During the third quarter

Summary of Quarterly Financial

Summary of Quarterly Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Information (unaudited)	Summary of Quarterly Financial Information (unaudited) The quarterly results of operations of our company for the years ended December 31, 2020, 2019 and 2018 are as follows (amounts in thousands): March 31, 2020 June 30, 2020 September 30, 2020 December 31, 2020 Revenues $ 170,224 $ 141,030 $ 146,575 $ 151,399 Operating income $ 26,973 $ 334 $ 11,928 $ 19,426 Net income (loss) $ 8,288 $ (19,618) $ (12,269) $ 710 Net income (loss) attributable to common stockholders $ 7,238 $ (20,665) $ (13,319) $ (340) Net income (loss) per share attributable to common stockholders: Basic and diluted $ 0.02 $ (0.07) $ (0.05) $0.00 March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 Revenues $ 167,293 $ 176,244 $ 192,873 $ 194,933 Operating income $ 26,076 $ 36,239 $ 45,279 $ 47,112 Net income $ 9,856 $ 18,930 $ 26,784 $ 28,720 Net income attributable to common unitholders $ 9,622 $ 18,696 $ 26,550 $ 27,679 Net income per share attributable to common unitholders: Basic and diluted $ 0.03 $ 0.06 $ 0.09 $ 0.09 March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Revenues $ 167,271 $ 178,529 $ 186,402 $ 199,309 Operating income $ 34,164 $ 49,665 $ 48,538 $ 58,490 Net income $ 18,058 $ 30,184 $ 29,230 $ 39,781 Net income attributable to common unitholders $ 17,824 $ 29,950 $ 28,996 $ 39,547 Net income per share attributable to common unitholders: Basic and diluted $ 0.06 $ 0.10 $ 0.10 $ 0.13

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events     None.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II—Valuation and Qualifying Accounts (amounts in thousands) Description Balance At Additions Uncollectible Balance Year ended December 31, 2018 Allowance for doubtful accounts $ 1,607 $ (811) $ (289) $ 507

Schedule III - Real Estate and

Schedule III - Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III - Real Estate and Accumulated Depreciation	Schedule III—Real Estate and Accumulated Depreciation (amounts in thousands) Initial Cost to Cost Capitalized Gross Amount at Development Type Encumbrances Land and Development Costs Building & Improvements Carrying Land and Development Costs Buildings & Total Accumulated Date of Date Life on 111 West 33rd Street, New York, NY office / $ — $ 13,630 $ 244,461 $ 125,514 n/a $ 13,630 $ 369,975 $ 383,605 $ 70,495 1954 2014 various 1400 Broadway, New York, NY office / — — 96,338 86,939 — — 183,277 183,277 46,694 1930 2014 various 1333 Broadway, New York, NY office / 158,676 91,435 120,190 10,469 n/a 91,435 130,659 222,094 29,285 1915 2013 various 1350 Broadway, New York, NY office / — — 102,518 38,180 — — 140,698 140,698 38,967 1929 2013 various 250 West 57th Street, New York, NY office/ 173,835 2,117 5,041 163,843 n/a 2,117 168,884 171,001 49,958 1921 1953 various 501 Seventh Avenue, New York, NY office/ — 1,100 2,600 96,842 n/a 1,100 99,442 100,542 45,220 1923 1950 various 1359 Broadway, New York, NY office/ — 1,233 1,809 63,075 n/a 1,233 64,884 66,117 32,420 1924 1953 various 350 Fifth Avenue (Empire State Building), New York, NY office/ — 21,551 38,934 970,966 n/a 21,551 1,009,900 1,031,451 275,648 1930 2013 various One Grand Central Place, office/ — 7,240 17,490 268,333 n/a 7,222 285,841 293,063 123,509 1930 1954 various First Stamford Place, Stamford, CT office 178,943 22,952 122,739 75,458 n/a 24,861 196,288 221,149 91,678 1986 2001 various One Station Place, Stamford, CT (Metro Center) office 87,236 5,313 28,602 19,581 n/a 5,313 48,183 53,496 31,903 1987 1984 various 383 Main Avenue, Norwalk, CT office 29,668 2,262 12,820 30,878 n/a 2,262 43,698 45,960 15,901 1985 1994 various 500 Mamaroneck Avenue, Harrison, NY office — 4,571 25,915 26,708 n/a 4,571 52,623 57,194 26,760 1987 1999 various 10 Bank Street, White Plains, NY office 31,624 5,612 31,803 20,833 n/a 5,612 52,636 58,248 25,537 1989 1999 various 10 Union Square, New York, NY retail 49,365 5,003 12,866 2,579 n/a 5,003 15,445 20,448 8,687 1987 1996 various 1542 Third Avenue, New York, NY retail 29,592 2,239 15,266 464 n/a 2,239 15,730 17,969 8,644 1991 1999 various 1010 Third Avenue, New York, NY and 77 West 55th Street, New York, NY retail 36,990 4,462 15,817 1,251 n/a 4,463 17,067 21,530 9,500 1962 1998 various 69-97 Main Street, Westport, CT retail — 2,782 15,766 6,317 n/a 2,782 22,083 24,865 8,052 1922 2003 various 103-107 Main Street, Westport, CT retail — 1,243 7,043 360 n/a 1,260 7,386 8,646 2,754 1900 2006 various Property for development at the Transportation Hub in Stamford, CT land — 4,542 — 8,071 — 12,508 105 12,613 — n/a n/a n/a Totals $ 775,929 $ 199,287 $ 918,018 $ 2,016,661 $ — $ 209,162 $ 2,924,804 $ 3,133,966 $ 941,612 Empire State Realty OP, L.P. Notes to Schedule III—Real Estate and Accumulated Depreciation (amounts in thousands) 1 . Reconciliation of Investment Properties The changes in our investment properties for the years ended December 31, 2020, 2019 and 2018 are as follows: 2020 2019 2018 Balance, beginning of year $ 3,109,433 $ 2,884,486 $ 2,667,655 Acquisition of new properties — — — Improvements 104,060 255,924 256,496 Disposals (79,527) (30,977) (39,665) Balance, end of year $ 3,133,966 $ 3,109,433 $ 2,884,486 The unaudited aggregate cost of investment properties for federal income tax purposes as of December 31, 2020 was $2.8 billion. 2 . Reconciliation of Accumulated Depreciation The changes in our accumulated depreciation for the years ended December 31, 2020, 2019 and 2018 are as follows: 2020 2019 2018 Balance, beginning of year $ 862,534 $ 747,304 $ 656,900 Depreciation expense 158,605 146,207 130,069 Disposals (79,527) (30,977) (39,665) Balance, end of year $ 941,612 $ 862,534 $ 747,304 Depreciation of investment properties reflected in the combined statements of income is calculated over the estimated original lives of the assets as follows: Buildings 39 years Building improvements 39 years or useful life Tenant improvements Term of related lease

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	The accompanying consolidated financial statements, have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and with the rules and regulations of the Securities and Exchange Commission (the "SEC"), represent our assets and liabilities and operating results. The consolidated financial statements include our accounts and our wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.
Consolidation, Variable Interest Entity	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 as well as whether the entity is a variable interest entity (“VIE”) and whether we are 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. We had no VIEs as of December 31, 2020 and 2019.    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 consolidated balance sheets and in the 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 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, goodwill, right-of-use-assets and other long-lived assets, estimate of tenant expense reimbursements, valuation of the allowance for doubtful accounts, and valuation of derivative instruments, ground lease liabilities, senior unsecured notes, mortgage notes payable, unsecured revolving credit and term loan 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.
Revenue Recognition and Other Revenues and Fees	Rental Revenue Rental revenue includes base rents that each tenant pays in accordance with the terms of its respective lease and is reported on a straight-line basis over the non-cancellable term of the lease which includes the effects of rent steps and rent abatements under the leases. In general, we commence rental revenue recognition when the tenant takes possession of the leased space or controls the physical use of the leased space and the leased space is substantially ready for its intended use. We account for all of our leases as operating leases. Deferred rent receivables, including free rental periods and leasing arrangements allowing for increased base rent payments, are accounted for in a manner that provides an even amount of fixed lease revenues over the respective non-cancellable lease terms. Differences between rental income recognized and amounts due under the respective lease agreements are recognized as an increase or decrease to deferred rent receivables. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in an index such as the Consumer Price Index over the index value in effect during a base year, or contain fixed percentage increases over the base rent to cover escalations. For Coronavirus 2019 (“COVID-19”) pandemic related rent deferral agreements, we will generally elect to record rental revenue and a receivable during the deferral period. We recognize rental revenue of acquired in-place above- and below-market leases at their fair values over the terms of the respective leases, including, for below-market leases, fixed option renewal periods, if any. Lease termination fees are recognized when the fees are determinable, tenant vacancy has occurred, collectability is reasonably assured, we have no continuing obligation to provide services to such former tenants and the payment is not subject to any conditions that must be met or waived. Observatory Revenue Revenues from the sale of Observatory tickets are recognized upon admission or ticket expirations. Deferred revenue related to unused and unexpired tickets as of December 31, 2020 and 2019 was $0.8 million and $2.7 million, respectively, and is included in deferred revenue and other liabilities on the consolidated balance sheets. Gains on Sale of Real Estate We record a gain on sale of real estate pursuant to provisions under Accounting Standards Codification (ASC) 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets. Under ASC 610-20, we must first determine whether the transaction is a sale to a customer or non-customer. We do not sell real estate within the ordinary course of our business and therefore, expect that sale transactions will not be contracts with customers. We will next determine whether we would have a controlling financial interest in the property after the sale. If we determine that we do not have a controlling financial interest in the real estate, we would evaluate whether a contract exists under ASC 606 Revenue from Contracts with Customers and whether the buyer has obtained control of the asset that was sold. We recognize the full gain on sale of real estate when the derecognition criteria under ASC 610-20 have been met. Third-Party Management and Other Fees We earn revenue arising from contractual agreements with related party entities for asset and property management services. This revenue is recognized as the related services are performed under the respective agreements in place.
Advertising and Marketing Costs	Advertising and marketing costs are expensed as incurred.
Real Estate Properties and Related Intangible Assets	Land and buildings and improvements are recorded at cost less accumulated depreciation and amortization. The recorded cost includes cost of acquisitions, development and construction and tenant allowances and improvements. Expenditures for ordinary repairs and maintenance are charged to property operating expense as incurred. Significant replacements and betterments which improve or extend the life of the asset are capitalized. Tenant improvements which improve or extend the life of the asset are capitalized. If a tenant vacates its space prior to the contractual termination of its lease, the unamortized balance of any tenant improvements are written off if they are replaced or have no future value. For developed properties, direct and indirect costs that clearly relate to projects under development are capitalized. Costs include construction costs, professional services such as architectural and legal costs, capitalized interest and direct payroll costs. We begin capitalization when the project is probable. The assets relating to the project are stated at cost and are not depreciated. Once construction is completed and the assets are placed in service, the assets are reclassified to the appropriate asset class and depreciated in accordance with the useful lives as indicated below. Capitalization of interest ceases when the asset is ready for its intended use, which is generally near the date that a certificate of occupancy is obtained. Total capitalized interest for the years ended December 31, 2019 and 2018 was $1.4 million and $1.6 million, respectively. There was no capitalized interest for the year ended December 31, 2020. Depreciation and amortization are computed using the straight-line method for financial reporting purposes. Buildings and improvements are depreciated over the shorter of 39 years, the useful life, or the remaining term of any leasehold interest. Tenant improvement costs, which are included in building and improvements in the consolidated balance sheets, are depreciated over the shorter of (i) the related remaining lease term or (ii) the life of the improvement. Corporate equipment, which is included in “Other assets,” is depreciated over three Acquisitions of properties are accounted for utilizing the acquisition method and accordingly the purchase cost is allocated to tangible and intangible assets and liabilities based on their fair values. The fair value of tangible assets acquired is determined by valuing the property as if it were vacant, applying methods similar to those used by independent appraisers of income-producing property. The resulting value is then allocated to land, buildings and improvements, and tenant improvements based on our determination of the fair value of these assets. The assumptions used in the allocation of fair values to assets acquired are based on our best estimates at the time of evaluation. Fair value is assigned to above-market and below-market leases based on the difference between (a) the contractual amounts to be paid by the tenant based on the existing lease and (b) our estimate of current market lease rates for the corresponding in-place leases, over the remaining terms of the in-place leases. Capitalized above-market lease amounts are amortized as a decrease to rental revenue over the remaining terms of the respective leases. Capitalized below-market lease amounts are amortized as an increase to rental revenue over the remaining terms of the respective leases. If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The aggregate value of other acquired intangible assets consists of acquired ground leases and acquired in-place leases and tenant relationships. The fair value allocated to acquired in-place leases consists of a variety of components including, but not necessarily limited to: (a) the value associated with avoiding the cost of originating the acquired in-place leases (i.e. the market cost to execute a lease, including leasing commissions, if any); (b) the value associated with lost revenue related to tenant reimbursable operating costs estimated to be incurred during the assumed lease-up period (i.e. real estate taxes, insurance and other operating expenses); (c) the value associated with lost rental revenue from existing leases during the assumed lease-up period; and (d) the value associated with any other inducements to secure a tenant lease.
Cash and Cash Equivalents and Restricted Cash	Cash and cash equivalents consist of cash on hand, government money markets, demand deposits with financial institutions and short-term liquid investments with original maturities of three months or less when purchased. Cash and cash equivalents held at major commercial banks may at times exceed the Federal Deposit Insurance Corporation limit. To date, we have not experienced any losses on our invested cash.Restricted cash consists of amounts held for tenants in accordance with lease agreements such as security deposits and amounts held by lenders and/or escrow agents to provide for future real estate tax expenditures and insurance expenditures, tenant vacancy related costs and debt service obligations.
Short-term Investments	Short-term investments include time deposits with original maturities of greater than three months and remainingmaturities of less than one year.
Tenant and Other Receivables	Tenant and other receivables, other than deferred rent receivable, are generally expected to be collected within one year.
Deferred Leasing Costs and Deferred Financing Costs	Deferred leasing costs consist of fees incurred to initiate and renew leases, are amortized on a straight-line basis over the related lease term and the expense is included in depreciation and amortization in our consolidated statements of income. Upon the early termination of a lease, unamortized deferred leasing costs are charged to expense.Fees and costs incurred to obtain long-term financing have been deferred and are amortized as a component of interest expense in our consolidated statements of income over the life of the respective long-term financing on the straight-line method which approximates the effective interest method. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking debt, which do not close, are expensed in the period in which it is determined that the financing will not close.
Equity Method Investments	We account for investments under the equity method of accounting where we do not have control but have the ability to exercise significant influence. Under this method, investments are recorded at cost, and the investment accounts are adjusted for our share of the entities’ income or loss and for distributions and contributions. Equity income (loss) is allocated based on the portion of the ownership interest that is controlled by us. The agreements may designate different percentage allocations among investors for profits and losses; however, our recognition of the entity’s income or loss generally follows the entity’s distribution priorities, which may change upon the achievement of certain investment return thresholds. To the extent that we contributed assets to an entity, our investment in the entity is recorded at cost basis in the assets that were contributed to the entity. Upon contributing assets to an entity, we make a judgment as to whether the economic substance of the transaction is a sale. In accordance with the provisions of ASC 610-20, we will recognize a full gain on both the retained and sold portions of real estate contributed or sold to an entity by recognizing our new equity method investment interest at fair value. To the extent that the carrying amount of these investments on our combined balance sheets is different than the basis reflected at the entity level, the basis difference would be amortized over the life of the related asset and included in our share of equity in net income of the entity. On a periodic basis, we assess whether there are any indicators that the carrying value of our investments in entities may be impaired on an other than temporary basis. An investment is impaired only if management’s estimate of the fair value of the investment is less than the carrying value of the investment on an other than temporary basis. To the extent impairment has occurred, the loss shall be measured as the excess of the carrying value of the investment over the fair value of the investment. As of December 31, 2020 and 2019, we had no equity method investments.
Goodwill	Goodwill is tested annually for impairment and is tested for impairment more frequently if events and circumstances indicate that the asset might be impaired. An impairment loss is recognized to the extent that the carrying amount, including goodwill, exceeds the reporting unit’s fair value and the implied fair value of goodwill is less than the carrying amount of that goodwill. Non-amortizing intangible assets, such as trade names and trademarks, are subject to an annual impairment test based on fair value and amortizing intangible assets are tested whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. In compliance with the requirements of authorities, we closed the Empire State Building Observatory on March 16, 2020 due to the COVID-19 pandemic and it remained closed until the 86th floor observation deck was reopened on July 20, 2020. The 102nd observation deck was reopened on August 24, 2020. The closure of our Observatory and subsequent reopening under international, national, and local travel restrictions and quarantines caused us during the quarter to choose to perform an impairment test related to goodwill. We engaged a third-party valuation consulting firm to perform the valuation process. The analysis used a combination of the discounted cash flow method (a form of the income approach) utilizing Level 3 unobservable inputs and the guideline company method (a form of the market approach). Significant assumptions under the former included revenue and cost projections, weighted average cost of capital, long-term growth rate and income tax considerations while the latter included guideline company enterprise values, revenue multiples and control premium rates. Our methodology to review goodwill impairment, which included a significant amount of judgment and estimates, provided a reasonable basis to determine whether impairment had occurred. Based upon the results of the goodwill impairment test of the stand-alone Observatory reporting unit, which is after the intercompany rent expense paid to the Real Estate reporting unit, we determined that the fair value of the Observatory reporting unit exceeded its carrying value by less than 5.0%. Many of the factors employed in determining whether or not goodwill is impaired are outside of our control and it is reasonably likely that assumptions and estimates will change in future periods. We will continue to assess the impairment of the Observatory reporting unit goodwill going forward and that continued assessment may again utilize a third-party valuation consulting firm.
Fair Value	Fair value is a market-based measurement, not an entity-specific measurement, and should be determined based on the assumptions that market participants would use in pricing the asset or liability. As a basis for considering market participant assumptions in fair value measurements, the FASB guidance establishes a fair value hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within levels one and two of the hierarchy) and the reporting entity's own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy). The methodologies used for valuing financial instruments have been categorized into three broad levels as follows: Level 1 - Quoted prices in active markets for identical instruments. Level 2 - Valuations based principally on other observable market parameters, including: • Quoted prices in active markets for similar instruments; • Quoted prices in less active or inactive markets for identical or similar instruments; • Other observable inputs (such as risk free interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates); and • Market corroborated inputs (derived principally from or corroborated by observable market data). Level 3 - Valuations based significantly on unobservable inputs, including: • Valuations based on third-party indications (broker quotes or counterparty quotes) which were, in turn, based significantly on unobservable inputs or were otherwise not supportable; and • Valuations based on internal models with significant unobservable inputs. These levels form a hierarchy. We follow this hierarchy for our financial instruments measured or disclosed at fair value on a recurring and nonrecurring basis and other required fair value disclosures. The classifications are based on the lowest level of input that is significant to the fair value measurement. We use the following methods and assumptions in estimating fair value disclosures for financial instruments. Cash and cash equivalents, restricted cash, short term investments, tenant and other receivables, prepaid expenses and other assets, deferred revenue, tenant security deposits, accounts payable and accrued expenses carrying values approximate their fair values due to the short term maturity of these instruments. The fair value of derivative instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Although the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by ourselves and our counterparties. The impact of such credit valuation adjustments, determined based on the fair value of each individual contract, was not significant to the overall valuation. As a result, all of our derivatives were classified as Level 2 of the fair value hierarchy.
Derivative Instruments	We are exposed to the effect of interest rate changes and manage these risks by following policies and procedures including the use of derivatives. To manage exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices. We also hedged our exposure to the variability in future cash flows for forecast transactions through June 30, 2020 (excluding forecast transactions related to the payment of variable interest on existing financial instruments). We record all derivatives on the balance sheet at fair value. We incorporate credit valuation adjustments to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. We measure the credit risk of our derivative instruments that are subject to master netting agreements on a net basis by counterparty portfolio. For derivatives that qualify as cash flow hedges, we report the gain or loss on the derivative designated as a hedge as part of other comprehensive income (loss) and subsequently reclassify the gain or loss into income in the period that the hedged transaction affects income.
Income Taxes	We are generally not subject to federal and state income taxes as our taxable income or loss is reportable by our partners. Accordingly, no provision has been made for federal and state income taxes. ESRT has elected, together with ESRT Observatory TRS, L.L.C., our subsidiary which holds our observatory operations, to treat ESRT Observatory TRS, L.L.C. as a TRS. ESRT has elected, together with ESRT Holdings TRS, L.L.C., our subsidiary that holds our third party management, restaurant, cafeteria, health clubs and certain cleaning operations, to treat ESRT Holdings TRS, L.L.C. as a TRS. TRSs may participate in non-real estate activities and/or perform non-customary services for tenants and their operations are generally subject to regular corporate income taxes. Our TRSs account for their income taxes in accordance with GAAP, which includes an estimate of the amount of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in our financial statements or tax returns. The calculation of the TRSs' tax provisions may require interpreting tax laws and regulations and could result in the use of judgments or estimates which could cause its recorded tax liability to differ from the actual amount due. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The TRSs periodically assess the realizability of deferred tax assets and the adequacy of deferred tax liabilities, including the results of local, state, or federal statutory tax audits or estimates and judgments used.    We apply provisions for measuring and recognizing tax benefits associated with uncertain income tax positions. Penalties and interest, if incurred, would be recorded as a component of income tax expense.
Share-Based Compensation	Share-based compensation for market based equity awards is measured at the fair value of the award on the date of grant and recognized as an expense on a straight-line basis over the stated vesting period, which is generally three or four years, depending on retirement eligibility. Share-based compensation for time-based equity awards is measured at the fair value of the award on the date of grant and recognized as an expense on a straight-line basis over the shorter of (i) the stated vesting period, which is generally three or four years, or (ii) the period from the date of grant to the date the employee becomes retirement eligible, which may occur upon grant.  An employee is retirement eligible when the employee attains the (i) age of 60 or 65, as applicable, and (ii) the date on which the employee has first completed ten years of continuous service with ESRT or its affiliates.     The determination of fair value of these awards is subjective and involves significant estimates and assumptions including expected volatility of ESRT stock, expected dividend yield, expected term, and assumptions of whether these awards will achieve parity with other operating partnership units or achieve performance thresholds. We believe that the assumptions and estimates utilized are appropriate based on the information available to management at the time of grant.
Per Unit Data	Basic and diluted earnings per unit are computed based upon the weighted average number of shares outstanding during the respective period.
Segment Reporting	We have identified two reportable segments: (1) Real Estate and (2) Observatory. Our real estate segment includes all activities related to the ownership, management, operation, acquisition, repositioning and disposition of our real estate assets. Our observatory segment operates the 86th and 102nd floor observatories at the Empire State Building. These two lines of businesses are managed separately because each business requires different support infrastructures, provides different services and has dissimilar economic characteristics such as investments needed, stream of revenues and different marketing strategies. We account for intersegment sales and rent as if the sales or rent were to third parties, that is, at current market prices.
Recently Issued or Adopted Accounting Standards	During April 2020, the Financial Accounting Standards Board ("FASB") staff issued a question and answer document (the “Lease Modification Q&A”) focused on the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 global pandemic. Under existing lease guidance, the entity would have to determine, on a lease by lease basis, if a lease concession was the result of a new arrangement reached with the tenant, which would be accounted for under the lease modification framework, or if a lease concession was under the enforceable rights and obligations that existed in the original lease, which would be accounted for outside the lease modification framework. The Lease Modification Q&A provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. During March 2020, the FASB issued Accounting Standards Update ("ASU") 2020-04, Reference Rate Reform (Topic 848). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the first quarter 2020, we elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. During January 2017, the FASB issued 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 adopted this standard and related amendments on January 1, 2020 and such adoption did not have a material impact 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. During November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, which clarifies that receivables arising from operating leases are not within the scope of Topic 326. Instead, impairment of receivables arising from operating leases should be accounted in accordance with ASU No. 2016-02, Leases (Topic 842). ASU No. 2016-13 and ASU No. 2018-19 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 adopted these standards on January 1, 2020 and such adoption did not have a material impact our consolidated financial statements.

Deferred Costs, Acquired Leas_2

Deferred Costs, Acquired Lease Intangibles and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Deferred Costs, Net	Deferred costs, net, consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Leasing costs $ 203,905 $ 199,033 Acquired in-place lease value and deferred leasing costs 181,336 200,296 Acquired above-market leases 40,398 49,213 425,639 448,542 Less: accumulated amortization (223,918) (224,598) Total deferred costs, net, excluding net deferred financing costs $ 201,721 $ 223,944 2020 2019 Financing costs $ 35,365 $ 25,315 Less: accumulated amortization (17,998) (13,863) Total deferred financing costs, net $ 17,367 $ 11,452
Schedule of Amortizing Acquired Intangible Assets and Liabilities	Amortizing acquired intangible assets and liabilities consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (52,181) (44,350) Acquired below-market ground leases, net $ 344,735 $ 352,566 2020 2019 Acquired below-market leases $ (78,451) $ (100,472) Less: accumulated amortization 46,746 60,793 Acquired below-market leases, net $ (31,705) $ (39,679)
Schedule of Future Amortization Expense and Rental Revenue from Acquired Intangible Assets	We expect to recognize amortization expense and rental revenue from the acquired intangible assets and liabilities as follows (amounts in thousands): For the year ending: Future Ground Rent Amortization Future Amortization Expense Future Rental Revenue 2021 $ 7,831 $ 10,977 $ 2,850 2022 7,831 10,175 3,169 2023 7,831 9,622 3,129 2024 7,831 7,757 2,566 2025 7,831 6,652 2,558 Thereafter 305,580 16,740 4,082 $ 344,735 $ 61,923 $ 18,354

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following as of December 31, 2020 and 2019 (amounts in thousands): As of December 31, 2020 Principal Balance as Principal Balance as Stated Effective (1) Maturity (2) Fixed rate mortgage debt Metro Center $ 87,382 $ 89,650 3.59 % 3.68 % 11/5/2024 10 Union Square 50,000 50,000 3.70 % 3.97 % 4/1/2026 1542 Third Avenue 30,000 30,000 4.29 % 4.53 % 5/1/2027 First Stamford Place (3) 180,000 180,000 4.28 % 4.78 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,477 38,251 4.01 % 4.23 % 1/5/2028 250 West 57th Street 180,000 — 2.83 % 3.27 % 12/1/2030 10 Bank Street 32,025 32,920 4.23 % 4.36 % 6/1/2032 383 Main Avenue 30,000 30,000 4.44 % 4.55 % 6/30/2032 1333 Broadway 160,000 160,000 4.21 % 4.29 % 2/5/2033 Total mortgage debt 786,884 610,821 Senior unsecured notes: (4) Series A 100,000 100,000 3.93 % 3.96 % 3/27/2025 Series B 125,000 125,000 4.09 % 4.12 % 3/27/2027 Series C 125,000 125,000 4.18 % 4.21 % 3/27/2030 Series D 115,000 115,000 4.08 % 4.11 % 1/22/2028 Series E 160,000 160,000 4.26 % 4.27 % 3/22/2030 Series F 175,000 175,000 4.44 % 4.45 % 3/22/2033 Series G 100,000 — 3.61 % 4.89 % 3/17/2032 Series H 75,000 — 3.73 % 5.00 % 3/17/2035 Unsecured revolving credit facility (4) — — LIBOR plus 1.10% — % 8/29/2021 Unsecured term loan facility (4) 215,000 265,000 LIBOR plus 1.20% 3.84 % 3/19/2025 Unsecured term loan facility (4) 175,000 — LIBOR plus 1.50% 3.04 % 12/31/2026 Total principal 2,151,884 1,675,821 Deferred financing costs, net (15,235) (7,247) Total $ 2,136,649 $ 1,668,574 _____________ (1) The effective rate is the yield as of December 31, 2020, including the effects of debt issuance costs and interest rate swaps. (2) Pre-payment is generally allowed for each loan upon payment of a customary pre-payment penalty. (3) Represents a $164 million mortgage loan bearing interest of 4.09% and a $16 million loan bearing interest at 6.25%. (4) At December 31, 2020, we were in compliance with all debt covenants.
Schedule of Maturities of Long-term Debt	Aggregate required principal payments at December 31, 2020 are as follows (amounts in thousands): Year Amortization Maturities Total 2021 $ 4,090 $ — $ 4,090 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 2025 5,826 315,000 320,826 Thereafter 20,084 1,707,747 1,727,831 Total principal maturities $ 51,462 $ 2,100,422 $ 2,151,884
Schedule of Deferred Costs, Net	Deferred costs, net, consisted of the following at December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Leasing costs $ 203,905 $ 199,033 Acquired in-place lease value and deferred leasing costs 181,336 200,296 Acquired above-market leases 40,398 49,213 425,639 448,542 Less: accumulated amortization (223,918) (224,598) Total deferred costs, net, excluding net deferred financing costs $ 201,721 $ 223,944 2020 2019 Financing costs $ 35,365 $ 25,315 Less: accumulated amortization (17,998) (13,863) Total deferred financing costs, net $ 17,367 $ 11,452

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consist of the following as of December 31, 2020 and 2019 (amounts in thousands): 2020 2019 Accrued capital expenditures $ 58,057 $ 90,910 Accounts payable and accrued expenses 32,309 35,084 Interest rate swap agreements liability 8,849 13,330 Accrued interest payable 3,219 3,699 Due to affiliated companies 769 763 Total accounts payable and accrued expenses $ 103,203 $ 143,786

Financial Instruments and Fai_2

Financial Instruments and Fair Values (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of the Terms of Agreements and Fair Values of Derivative Financial Instruments	The table below summarizes the terms of agreements and the fair values of our derivative financial instruments as of December 31, 2020 and 2019 (dollar amounts in thousands): December 31, 2020 December 31, 2019 Derivative Notional Amount Receive Rate Pay Rate Effective Date Expiration Date Asset Liability Asset Liability Interest rate swap $ 265,000 1 Month LIBOR 2.1485 % August 31, 2017 August 24, 2022 $ — $ (8,849) $ — $ (4,247) Interest rate swap 125,000 3 Month LIBOR 2.9580 % July 1, 2019 July 1, 2026 — — — (9,083) $ — $ (8,849) $ — $ (13,330)
Summary of Effect of Derivative Financial Instruments Designated as Cash Flow Hedges	The table below shows the effect of our derivative financial instruments designated as cash flow hedges on accumulated other comprehensive income (loss) for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): Effects of Cash Flow Hedges December 31, 2020 December 31, 2019 December 31, 2018 Amount of gain (loss) recognized in other comprehensive income (loss) $ (19,322) $ (21,813) $ (2,721) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (8,870) (1,231) (1,845) The table below shows the effect of our derivative financial instruments designated as cash flow hedges on the consolidated statements of income for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): Effects of Cash Flow Hedges December 31, 2020 December 31, 2019 December 31, 2018 Total interest (expense) presented on the consolidated $ (89,907) $ (79,246) $ (79,623) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (8,870) (1,231) (1,845)
Schedule of the Aggregate Carrying Value of Debt and Estimates of Fair Value	The following tables summarize the carrying and estimated fair values of our financial instruments as of December 31, 2020 and 2019 (amounts in thousands): December 31, 2020 Carrying Value Estimated Fair Value Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses $ 8,849 $ 8,849 $ — $ 8,849 $ — Mortgage notes payable 775,929 808,294 — — 808,294 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,159 1,039,857 — — 1,039,857 Unsecured term loan facilities 387,561 390,000 — — 390,000 December 31, 2019 Carrying Value Estimated Fair Value Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses 13,330 13,330 — 13,330 — Mortgage notes payable 605,542 629,609 — — 629,609 Senior unsecured notes - Series A, B, C, D, E and F 798,392 843,394 — — 843,394 Unsecured term loan facility 264,640 265,000 — — 265,000

Leases Leases (Tables)

Leases Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Components of Rental Revenue	The components of rental revenue for the year ended December 31, 2020 and 2019 are as follows (amounts in thousands): Year Ended December 31, 2020 2019 Fixed payments $ 496,515 $ 510,799 Variable payments 66,556 75,615 Total rental revenue $ 563,071 $ 586,414
Schedule of Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received	As of December 31, 2020, we were entitled to the following future contractual minimum lease payments (excluding operating expense reimbursements) on non-cancellable operating leases to be received which expire on various dates through 2038 (amounts in thousands): 2021 $ 492,574 2022 489,185 2023 468,877 2024 431,204 2025 391,228 Thereafter 1,846,423 $ 4,119,491
Schedule of Future Minimum Lease Payments	As of December 31, 2020, the following table summarizes our future minimum lease payments with the amounts discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): 2021 $ 1,518 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted lease payments 72,852 Present value discount (43,748) Ground lease liabilities $ 29,104

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Summary of Percent of Total Rental Revenue	For the years ended December 31, 2020, 2019 and 2018, the six properties listed below accounted for the indicated percentage of total rental revenues. No other property accounted for more than 5.0% of total rental revenues. Year Ended December 31, 2020 2019 2018 Empire State Building 32.8 % 32.9 % 31.9 % One Grand Central Place 12.4 % 12.3 % 12.8 % 111 West 33rd Street 10.5 % 9.9 % 9.3 % 1400 Broadway 8.0 % 7.1 % 7.1 % 250 West 57th Street 5.7 % 5.5 % 5.2 % First Stamford Place 5.4 % 5.4 % 5.9 %
Schedule of Contributions to Multiemployer Plans	Contributions we made to the multi-employer plans for the years ended December 31, 2020, 2019 and 2018 are included in the table below (amounts in thousands): For the Year Ended December 31, Benefit Plan 2020 2019 2018 Pension Plans (pension and annuity)* $ 2,383 $ 3,418 $ 3,327 Health Plans** 6,873 10,055 9,373 Other*** 416 641 814 Total plan contributions $ 9,672 $ 14,114 $ 13,514 * Pension plans include $0.8 million, $1.0 million and $1.0 million for the years ended 2020, 2019 and 2018, respectively, to multiemployer plans not discussed above. ** Health plans include $1.4 million, $1.8 million and $1.6 million for the years ended 2020, 2019 and 2018, respectively, to multiemployer plans not discussed above. *** Other consists of union costs which were not itemized between pension and health plans. Other includes $0.3 million, $0.4 million and $0.2 million for the years ended 2020, 2019 and 2018, respectively, in connection with other multiemployer plans not discussed above.

Capital (Tables)

Capital (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of Equity Securities Repurchased	The following table summarizes our purchases of equity securities for the year ended December 31, 2020: Period Total Number of Shares Purchased Average Price Paid Per Share Total Number of Shares Purchased as Part of Publicly Announced Plan Maximum Approximate Dollar Value Available for Future Purchase (in thousands) Year ended December 31, 2020 17,279,252 $ 8.32 17,279,252 $ 356,287
Dividends Declared	The following table summarizes the distributions paid on our operating partnership units for the years ended December 31, 2020, 2019 and 2018: Record Date Payment Date Amount per Operating Partnership Unit June 19, 2020 June 30, 2020 $0.105 March 16, 2020 March 31, 2020 $0.105 December 23, 2019 December 31, 2019 $0.105 September 16, 2019 September 30, 2019 $0.105 June 14, 2019 June 28, 2019 $0.105 March 15, 2019 March 29, 2019 $0.105 December 17, 2018 December 31, 2018 $0.105 September 14, 2018 September 28, 2018 $0.105 June 15, 2018 June 29, 2018 $0.105 March 15, 2018 March 30, 2018 $0.105
Summary of Restricted Stock and Long-Term Incentive Plan Activity	The following is a summary of ESRT restricted stock and LTIP unit activity for the year ended December 31, 2020: ESRT Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2019 118,918 5,986,569 $ 9.73 Vested (58,326) (1,052,692) 14.04 Granted 161,449 5,042,810 5.44 Forfeited or unearned (4,341) (2,226,403) 7.55 Unvested balance at December 31, 2020 217,700 7,750,284 $ 6.94
Schedule of Earnings Per Unit, Basic and Diluted	Earnings per unit for the years ended December 31, 2020, 2019 and 2018 is computed as follows (amounts in thousands, except per share amounts): For the Year Ended December 31, 2020 2019 2018 Numerator: Net income (loss) $ (22,889) $ 84,290 $ 117,253 Private perpetual preferred unit distributions (4,197) (1,743) (936) Earnings allocated to unvested shares (985) (885) (851) Net income (loss) attributable to common unitholders - basic and diluted $ (28,071) $ 81,662 $ 115,466 Denominator: Weighted average units outstanding - basic 283,826 297,798 297,258 Effect of dilutive securities: Stock-based compensation plans 11 — 1 Weighted average shares outstanding - diluted 283,837 297,798 297,259 Earnings per unit - basic and diluted $ (0.10) $ 0.27 $ 0.39

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	TRS Holdings and Observatory TRS are taxable entities and their consolidated provision for income taxes consisted of the following for the years ended December 31, 2020, 2019 and 2018 (amounts in thousands): For the Year Ended December 31, 2020 2019 2018 Current: Federal $ 4,932 $ (1,077) $ (2,389) State and local 2,699 (872) (2,253) Total current 7,631 (1,949) (4,642) Deferred: Federal (340) (248) — State and local (320) (232) — Total deferred (660) (480) — Income tax benefit (expense) $ 6,971 $ (2,429) $ (4,642)
Schedule of Actual Tax Provision Differed From Federal Statutory Corporate Rate	The actual tax provision differed from that computed at the federal statutory corporate rate as follows (amounts in thousands): For the Year Ended December 31, 2020 2019 2018 Federal tax benefit (expense) at statutory rate $ 2,544 $ (1,575) $ (2,844) State income tax benefit (expense), net of federal benefit 2,379 (854) (1,798) Corporate income tax rate adjustment 2,048 — — Income tax benefit (expense) $ 6,971 $ (2,429) $ (4,642)
Schedule of Deferred Tax Assets and Liabilities	The income tax effects of temporary differences that give rise to deferred tax assets are presented below as of December 31, 2020, 2019 and 2018 (amounts in thousands): 2020 2019 2018 Deferred tax assets: Deferred revenue on unredeemed observatory admission ticket sales $ 256 $ 916 $ 1,396 New York City net operating loss carryforward credit 334 — — Deferred tax assets $ 590 $ 916 $ 1,396

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables provide components of segment profit for each segment for the years ended December 31, 2020, 2019 and 2018, as reviewed by management (amounts in thousands): 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 563,071 $ — $ — $ 563,071 Intercompany rental revenue 17,827 — (17,827) — Observatory revenue — 29,057 — 29,057 Lease termination fees 9,416 — — 9,416 Third-party management and other fees 1,225 — — 1,225 Other revenue and fees 6,459 — — 6,459 Total revenues 597,998 29,057 (17,827) 609,228 Operating expenses: Property operating expenses 136,141 — — 136,141 Intercompany rent expense — 17,827 (17,827) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 62,244 — — 62,244 Observatory expenses — 23,723 — 23,723 Real estate taxes 121,923 — — 121,923 Impairment charges 6,204 — — 6,204 Depreciation and amortization 190,863 143 — 191,006 Total operating expenses 526,701 41,693 (17,827) 550,567 Total operating income (loss) 71,297 (12,636) — 58,661 Other income (expense): Interest income 2,542 95 — 2,637 Interest expense (89,907) — — (89,907) Loss on early extinguishment of debt (86) — — (86) IPO litigation expense (1,165) — — (1,165) Loss before income taxes (17,319) (12,541) — (29,860) Income tax (expense) benefit (843) 7,814 — 6,971 Net loss $ (18,162) $ (4,727) $ — $ (22,889) Segment assets $ 3,903,884 $ 246,811 $ — $ 4,150,695 Expenditures for segment assets $ 101,306 $ 2,754 $ — $ 104,060 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 586,414 $ — $ — $ 586,414 Intercompany rental revenue 82,469 — (82,469) — Observatory revenue — 128,769 — 128,769 Lease termination fees 4,352 — — 4,352 Third-party management and other fees 1,254 — — 1,254 Other revenue and fees 10,554 — — 10,554 Total revenues 685,043 128,769 (82,469) 731,343 Operating expenses: Property operating expenses 174,977 — — 174,977 Intercompany rent expense — 82,469 (82,469) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 61,063 — — 61,063 Observatory expenses — 33,767 — 33,767 Real estate taxes 115,916 — — 115,916 Depreciation and amortization 181,558 30 — 181,588 Total operating expenses 542,840 116,266 (82,469) 576,637 Total operating income 142,203 12,503 — 154,706 Other income (expense): Interest income 11,259 — — 11,259 Interest expense (79,246) — — (79,246) Income before income taxes 74,216 12,503 — 86,719 Income tax expense (896) (1,533) — (2,429) Net income $ 73,320 $ 10,970 $ — $ 84,290 Segment assets $ 3,671,211 $ 260,623 $ — $ 3,931,834 Expenditures for segment assets $ 191,630 $ 64,294 $ — $ 255,924 2018 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 493,231 $ — $ — $ 493,231 Intercompany rental revenue 79,954 — (79,954) — Tenant expense reimbursement 72,372 — — 72,372 Observatory revenue — 131,227 — 131,227 Lease termination fees 20,847 — — 20,847 Third-party management and other fees 1,440 — — 1,440 Other revenue and fees 12,394 — — 12,394 Total revenues 680,238 131,227 (79,954) 731,511 Operating expenses: Property operating expenses 167,379 — — 167,379 Intercompany rent expense — 79,954 (79,954) — Ground rent expense 9,326 — — 9,326 General and administrative expenses 52,674 — — 52,674 Observatory expenses — 32,767 — 32,767 Real estate taxes 110,000 — — 110,000 Depreciation and amortization 168,430 78 — 168,508 Total operating expenses 507,809 112,799 (79,954) 540,654 Total operating income 172,429 18,428 — 190,857 Other income (expense): Interest income 10,661 — — 10,661 Interest expense (79,623) — — (79,623) Income before income taxes 103,467 18,428 — 121,895 Income tax expense (1,114) (3,528) — (4,642) Net income $ 102,353 $ 14,900 $ — $ 117,253 Segment assets $ 3,930,330 $ 265,450 $ — $ 4,195,780 Expenditures for segment assets $ 201,685 $ 54,811 $ — $ 256,496

Summary of Quarterly Financia_2

Summary of Quarterly Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The quarterly results of operations of our company for the years ended December 31, 2020, 2019 and 2018 are as follows (amounts in thousands): March 31, 2020 June 30, 2020 September 30, 2020 December 31, 2020 Revenues $ 170,224 $ 141,030 $ 146,575 $ 151,399 Operating income $ 26,973 $ 334 $ 11,928 $ 19,426 Net income (loss) $ 8,288 $ (19,618) $ (12,269) $ 710 Net income (loss) attributable to common stockholders $ 7,238 $ (20,665) $ (13,319) $ (340) Net income (loss) per share attributable to common stockholders: Basic and diluted $ 0.02 $ (0.07) $ (0.05) $0.00 March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 Revenues $ 167,293 $ 176,244 $ 192,873 $ 194,933 Operating income $ 26,076 $ 36,239 $ 45,279 $ 47,112 Net income $ 9,856 $ 18,930 $ 26,784 $ 28,720 Net income attributable to common unitholders $ 9,622 $ 18,696 $ 26,550 $ 27,679 Net income per share attributable to common unitholders: Basic and diluted $ 0.03 $ 0.06 $ 0.09 $ 0.09 March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Revenues $ 167,271 $ 178,529 $ 186,402 $ 199,309 Operating income $ 34,164 $ 49,665 $ 48,538 $ 58,490 Net income $ 18,058 $ 30,184 $ 29,230 $ 39,781 Net income attributable to common unitholders $ 17,824 $ 29,950 $ 28,996 $ 39,547 Net income per share attributable to common unitholders: Basic and diluted $ 0.06 $ 0.10 $ 0.10 $ 0.13

Description of Business and O_2

Description of Business and Organization - Narrative (Details) ft² in Millions	12 Months Ended
	Dec. 31, 2020ft²entityoffice_and_propertyparcel$ / shares
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	10.1
Number of entities to be treated as taxable REIT subsidiary of ESRT | entity	2
Empire State Realty Trust | Empire State Realty OP
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
OP units owned by the Company (as a percent)	60.10%
ESRT | Empire State Realty Trust | Empire State Realty OP
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
OP units owned by the Company (as a percent)	60.10%
Common Class A | ESRT
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Par value (in dollars per share) | $ / shares	$ 0.01
Office Building
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	9.4
Number of properties | office_and_property	14
Office Building | Manhattan
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	7.6
Number of properties | office_and_property	9
Office Building | Fairfield County, Connecticut and Westchester County, New York
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	1.8
Number of properties | office_and_property	5
Development Parcel
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of properties | parcel	3
Retail | Manhattan and Westport, Connecticut
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	0.2
Retail | Manhattan
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	0.5
Number of properties | office_and_property	4
Retail | Westport, Connecticut
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of properties | office_and_property	2
Other Property | Stamford, Connecticut
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in sqft)	0.4

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jun. 30, 2020
Accounting Policies [Line Items]
Deferred revenue	$ 0.8	$ 2.7
Advertising and marketing expense	7.4	9.7	$ 8.9
Capitalized interest	$ 0	$ 1.4	$ 1.6
Number of reportable segments | segment	2
Observatory Reporting Unit
Accounting Policies [Line Items]
Fair value in excess of carrying value (less than) (as a percent)				5.00%
Building and Building Improvements
Accounting Policies [Line Items]
Useful life (in years)	39 years
Corporate Equipment | Minimum
Accounting Policies [Line Items]
Useful life (in years)	3 years
Corporate Equipment | Maximum
Accounting Policies [Line Items]
Useful life (in years)	7 years

Deferred Costs, Acquired Leas_3

Deferred Costs, Acquired Lease Intangibles and Goodwill - Schedule of Deferred Costs, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs [Line Items]
Leasing costs	$ 203,905	$ 199,033
Total deferred costs, gross	425,639	448,542
Less: accumulated amortization	(223,918)	(224,598)
Total deferred costs, net, excluding net deferred financing costs	201,721	223,944
Acquired in-place lease value and deferred leasing costs
Deferred Costs [Line Items]
Acquired intangible assets, gross	181,336	200,296
Acquired above-market leases
Deferred Costs [Line Items]
Acquired intangible assets, gross	$ 40,398	$ 49,213

Deferred Costs, Acquired Leas_4

Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2020	Dec. 31, 2013
Deferred Costs [Line Items]
Amortization of deferred leasing and acquired deferred leasing costs	$ 24,800	$ 24,500
Amortization of deferred leasing and acquired deferred leasing costs			$ 26,300
Amortization of acquired above and below-market leases, net	3,627	7,311	6,120
Goodwill	491,479	491,479
Observatory Reporting Unit
Deferred Costs [Line Items]
Fair value in excess of carrying value (less than) (as a percent)				5.00%
Empire State Building observatory operations
Deferred Costs [Line Items]
Goodwill					$ 227,500
Empire State Building
Deferred Costs [Line Items]
Goodwill					250,800
501 Seventh Avenue
Deferred Costs [Line Items]
Goodwill					$ 13,200
Lease agreements
Deferred Costs [Line Items]
Amortization expense related to acquired lease intangibles	$ 7,600	10,900	$ 12,100
Ground lease
Deferred Costs [Line Items]
Weighted-average amortization period (in years)	23 years 7 months 6 days
In-place leases and deferred leasing costs
Deferred Costs [Line Items]
Weighted-average amortization period (in years)	3 years 10 months 24 days
Above-market leases
Deferred Costs [Line Items]
Weighted-average amortization period (in years)	3 years 7 months 6 days
Below-market Lease
Deferred Costs [Line Items]
Weighted-average amortization period (in years)	3 years 8 months 12 days
Unsecured revolving credit facility | Revolving Credit Facility
Deferred Costs [Line Items]
Net deferred financing costs	$ 2,100	$ 4,200

Deferred Costs, Acquired Leas_5

Deferred Costs, Acquired Lease Intangibles and Goodwill - Acquired Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Acquired below-market ground leases	$ 396,916	$ 396,916
Less: accumulated amortization	(52,181)	(44,350)
Acquired below-market ground leases, net	344,735	352,566
Acquired below-market leases	(78,451)	(100,472)
Less: accumulated amortization	46,746	60,793
Acquired below-market leases, net	$ (31,705)	$ (39,679)

Deferred Costs, Acquired Leas_6

Deferred Costs, Acquired Lease Intangibles and Goodwill - Future Amortization Expense and Rental Revenue (Details) $ in Thousands	Dec. 31, 2020USD ($)
Future Rental Revenue [Abstract]
2020	$ 2,850
2021	3,169
2022	3,129
2023	2,566
2024	2,558
Thereafter	4,082
Future Rental Revenue	18,354
Ground lease
Future Amortization Expense [Abstract]
2020	7,831
2021	7,831
2022	7,831
2023	7,831
2024	7,831
Thereafter	305,580
Future Amortization Expense	344,735
Lease agreements
Future Amortization Expense [Abstract]
2020	10,977
2021	10,175
2022	9,622
2023	7,757
2024	6,652
Thereafter	16,740
Future Amortization Expense	$ 61,923

Debt - Schedule of Long term De

Debt - Schedule of Long term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Nov. 30, 2020	Mar. 17, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Unsecured revolving credit facility	$ 0			$ 0
Total principal	2,151,884,000
Deferred financing costs, net	(17,367,000)			(11,452,000)
Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate debt	786,884,000			610,821,000
Fixed rate mortgage debt | Metro Center
Debt Instrument [Line Items]
Fixed rate debt	$ 87,382,000			89,650,000
Stated Rate (as a percent)	3.59%
Effective Rate (as a percent)	3.68%
Fixed rate mortgage debt | 10 Union Square
Debt Instrument [Line Items]
Fixed rate debt	$ 50,000,000			50,000,000
Stated Rate (as a percent)	3.70%
Effective Rate (as a percent)	3.97%
Fixed rate mortgage debt | 1542 Third Avenue
Debt Instrument [Line Items]
Fixed rate debt	$ 30,000,000			30,000,000
Stated Rate (as a percent)	4.29%
Effective Rate (as a percent)	4.53%
Fixed rate mortgage debt | First Stamford Place
Debt Instrument [Line Items]
Fixed rate debt	$ 180,000,000			180,000,000
Stated Rate (as a percent)	4.28%
Effective Rate (as a percent)	4.78%
Fixed rate mortgage debt | First Stamford Place - First Lien
Debt Instrument [Line Items]
Stated Rate (as a percent)	4.09%
Face amount	$ 164,000,000
Fixed rate mortgage debt | First Stamford Place - Second Lien
Debt Instrument [Line Items]
Stated Rate (as a percent)	6.25%
Face amount	$ 16,000,000
Fixed rate mortgage debt | 1010 Third Avenue and 77 West 55th Street
Debt Instrument [Line Items]
Fixed rate debt	$ 37,477,000			38,251,000
Stated Rate (as a percent)	4.01%
Effective Rate (as a percent)	4.23%
Fixed rate mortgage debt | 250 West 57th Street
Debt Instrument [Line Items]
Fixed rate debt	$ 180,000,000	$ 180,000,000		0
Stated Rate (as a percent)	2.83%	2.83%
Effective Rate (as a percent)	3.27%
Fixed rate mortgage debt | 10 Bank Street
Debt Instrument [Line Items]
Fixed rate debt	$ 32,025,000			32,920,000
Stated Rate (as a percent)	4.23%
Effective Rate (as a percent)	4.36%
Fixed rate mortgage debt | 383 Main Avenue
Debt Instrument [Line Items]
Fixed rate debt	$ 30,000,000			30,000,000
Stated Rate (as a percent)	4.44%
Effective Rate (as a percent)	4.55%
Fixed rate mortgage debt | 1333 Broadway
Debt Instrument [Line Items]
Fixed rate debt	$ 160,000,000			160,000,000
Stated Rate (as a percent)	4.21%
Effective Rate (as a percent)	4.29%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series A
Debt Instrument [Line Items]
Total	$ 100,000,000			100,000,000
Stated Rate (as a percent)	3.93%
Effective Rate (as a percent)	3.96%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series B
Debt Instrument [Line Items]
Total	$ 125,000,000			125,000,000
Stated Rate (as a percent)	4.09%
Effective Rate (as a percent)	4.12%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series C
Debt Instrument [Line Items]
Total	$ 125,000,000			125,000,000
Stated Rate (as a percent)	4.18%
Effective Rate (as a percent)	4.21%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series D
Debt Instrument [Line Items]
Total	$ 115,000,000			115,000,000
Stated Rate (as a percent)	4.08%
Effective Rate (as a percent)	4.11%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series E
Debt Instrument [Line Items]
Total	$ 160,000,000			160,000,000
Stated Rate (as a percent)	4.26%
Effective Rate (as a percent)	4.27%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series F
Debt Instrument [Line Items]
Total	$ 175,000,000			175,000,000
Stated Rate (as a percent)	4.44%
Effective Rate (as a percent)	4.45%
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series G
Debt Instrument [Line Items]
Total	$ 100,000,000			0
Stated Rate (as a percent)	3.61%		3.61%
Effective Rate (as a percent)	4.89%
Face amount			$ 100,000,000
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Series H
Debt Instrument [Line Items]
Total	$ 75,000,000			0
Stated Rate (as a percent)	3.73%		3.73%
Effective Rate (as a percent)	5.00%
Face amount			$ 75,000,000
Mortgages, senior notes, and unsecured term loan facilities, not including unsecured revolving credit facility
Debt Instrument [Line Items]
Total principal	$ 2,151,884,000			1,675,821,000
Deferred financing costs, net	(15,235,000)			(7,247,000)
Total	2,136,649,000			1,668,574,000
Revolving Credit Facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Unsecured revolving credit facility	$ 0			0
Effective Rate (as a percent)	0.00%
Revolving Credit Facility | Unsecured revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.10%
Revolving Credit Facility | Unsecured term loan facility
Debt Instrument [Line Items]
Unsecured revolving credit facility	$ 215,000,000			265,000,000
Effective Rate (as a percent)	3.84%
Revolving Credit Facility | Unsecured term loan facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.20%
Revolving Credit Facility | Unsecured term loan facility
Debt Instrument [Line Items]
Unsecured revolving credit facility	$ 175,000,000			$ 0
Effective Rate (as a percent)	3.04%
Revolving Credit Facility | Unsecured term loan facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.50%

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Long-term Debt (Details) $ in Thousands	Dec. 31, 2020USD ($)
Amortization
2021	$ 4,090
2022	5,628
2023	7,876
2024	7,958
2025	5,826
Thereafter	20,084
Total principal maturities	51,462
Maturities
2021	0
2022	0
2023	0
2024	77,675
2025	315,000
Thereafter	1,707,747
Total principal maturities	2,100,422
Total
2021	4,090
2022	5,628
2023	7,876
2024	85,633
2025	320,826
Thereafter	1,727,831
Total principal maturities	$ 2,151,884

Debt - Schedule of Deferred Fin

Debt - Schedule of Deferred Financing Costs, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Financing costs	$ 35,365	$ 25,315
Less: accumulated amortization	(17,998)	(13,863)
Total deferred financing costs, net	17,367	11,452
Amortization expense related to deferred financing costs	4,100	3,800	$ 4,100
Revolving Credit Facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Net deferred financing costs	$ 2,100	$ 4,200

Debt - Mortgage Debt (Details)

Debt - Mortgage Debt (Details) - Fixed rate mortgage debt - USD ($) $ in Thousands	Dec. 31, 2020	Nov. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Fixed rate debt	$ 786,884		$ 610,821
250 West 57th Street
Debt Instrument [Line Items]
Fixed rate debt	$ 180,000	$ 180,000	$ 0
Stated interest rate (as a percent)	2.83%	2.83%

Debt - Unsecured Revolving Cred

Debt - Unsecured Revolving Credit and Term Loan Facilities (Details)	Mar. 19, 2020USD ($)option	Dec. 31, 2021	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Outstanding borrowings			$ 0	$ 0
Unsecured term loan facility | Unsecured revolving credit facility and term loan
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,315,000,000
Unsecured revolving credit facility higher borrowing capacity option	1,750,000,000
Unsecured term loan facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,100,000,000
Outstanding borrowings			0	0
Number of options to extend maturity | option	2
Extension period (in months)	6 months
Unsecured term loan facility | Term loan facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 215,000,000
Outstanding borrowings			215,000,000	265,000,000
Unsecured term loan facility | Unsecured term loan facility
Debt Instrument [Line Items]
Maximum borrowing capacity	175,000,000
Unsecured revolving credit facility higher borrowing capacity option	$ 225,000,000
Outstanding borrowings			$ 175,000,000	$ 0
Prepayment fee, as a percent of principal amount prepaid			2.00%
Unsecured term loan facility | Unsecured term loan facility | Forecast
Debt Instrument [Line Items]
Prepayment fee, as a percent of principal amount prepaid		1.00%
Minimum | Unsecured term loan facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Extension fee, as a percent of outstanding commitments under revolving credit facility	0.0625%
Maximum | Unsecured term loan facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Extension fee, as a percent of outstanding commitments under revolving credit facility	0.075%

Debt - Senior Unsecured Notes E

Debt - Senior Unsecured Notes Exchangeable (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2014
Debt Instrument [Line Items]
Interest expense	$ 89,907,000	$ 79,246,000	$ 79,623,000
Amortization of deferred financing costs	$ 4,100,000	3,800,000	4,100,000
Senior unsecured notes - exchangeable | Senior unsecured notes - exchangeable
Debt Instrument [Line Items]
Face amount				$ 250,000,000
Stated interest rate (as a percent)				2.625%
Interest expense on note		6,100,000	9,900,000
Interest expense		4,100,000	6,600,000
Accretion of debt discount		1,600,000	2,700,000
Amortization of deferred financing costs		$ 400,000	$ 600,000

Debt - Senior Unsecured Notes (

Debt - Senior Unsecured Notes (Details) - Senior unsecured notes - USD ($)	Mar. 17, 2020	Dec. 31, 2020
Series G and Series H senior unsecured notes
Line of Credit Facility [Line Items]
Face amount	$ 175,000,000
Issue price, as a percent of aggregate principal amount	100.00%
Series G
Line of Credit Facility [Line Items]
Face amount	$ 100,000,000
Stated interest rate (as a percent)	3.61%	3.61%
Series H
Line of Credit Facility [Line Items]
Face amount	$ 75,000,000
Stated interest rate (as a percent)	3.73%	3.73%

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued capital expenditures	$ 58,057	$ 90,910
Accounts payable and accrued expenses	32,309	35,084
Interest rate swap agreements liability	8,849	13,330
Accrued interest payable	3,219	3,699
Due to affiliated companies	769	763
Total accounts payable and accrued expenses	$ 103,203	$ 143,786

Financial Instruments and Fai_3

Financial Instruments and Fair Values - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Interest rate swap agreements liability	$ 8,849,000	$ 13,330,000
Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements liability	8,900,000
Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Unrealized loss on valuation of interest rate swap agreements		20,600,000
Loss expected to be reclassified within twelve months	11,500,000
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Aggregate notional value	265,000,000	390,000,000
Unrealized loss on valuation of interest rate swap agreements	10,500,000
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap, Three Month LIBOR, 2.9580%, Swap | LIBOR
Derivative [Line Items]
Notional amount	125,000,000
Payment of termination settlement fee	20,300,000
Accounts payable and accrued expenses | Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements liability	$ 8,800,000	$ 13,300,000

Financial Instruments and Fai_4

Financial Instruments and Fair Values - Terms of Agreements and Fair Value (Details) - Cash Flow Hedging - Designated as Hedging Instrument - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Asset	$ 0	$ 0
Liability	(8,849,000)	(13,330,000)
LIBOR | Interest Rate Swap, One Month LIBOR, 2.1485%
Derivatives, Fair Value [Line Items]
Notional Amount	$ 265,000,000
Pay Rate	2.1485%
Asset	$ 0	0
Liability	(8,849,000)	(4,247,000)
LIBOR | Interest Rate Swap, Three Month LIBOR, 2.9580%, Swap
Derivatives, Fair Value [Line Items]
Notional Amount	$ 125,000,000
Pay Rate	2.958%
Asset	$ 0	0
Liability	$ 0	$ (9,083,000)

Financial Instruments and Fai_5

Financial Instruments and Fair Values - Gain and Loss of Cash Flow Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (19,322)	$ (21,813)	$ (2,721)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(8,870)	(1,231)	(1,845)
Interest expense	(89,907)	(79,246)	(79,623)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	(19,322)	(21,813)	(2,721)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(8,870)	(1,231)	(1,845)
Accumulated other comprehensive income (loss) | Interest rate swaps | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (8,870)	$ (1,231)	$ (1,845)

Financial Instruments and Fai_6

Financial Instruments and Fair Values - Schedule of the aggregate carrying value of debt and estimates of fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	$ 8,849	$ 13,330
Mortgage notes payable | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	775,929	605,542
Mortgage notes payable | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	808,294	629,609
Mortgage notes payable | Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Mortgage notes payable | Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Mortgage notes payable | Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	808,294	629,609
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	973,159	798,392
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,039,857	843,394
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,039,857	843,394
Revolving Credit Facility | Unsecured term loan facility | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	387,561	264,640
Revolving Credit Facility | Unsecured term loan facility | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	390,000	265,000
Revolving Credit Facility | Unsecured term loan facility | Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Revolving Credit Facility | Unsecured term loan facility | Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Revolving Credit Facility | Unsecured term loan facility | Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	390,000	265,000
Interest rate swaps
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	8,900
Interest rate swaps | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	8,849	13,330
Interest rate swaps | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	8,849	13,330
Interest rate swaps | Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	0	0
Interest rate swaps | Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	8,849	13,330
Interest rate swaps | Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	$ 0	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	Dec. 31, 2020USD ($)property	Dec. 31, 2019USD ($)
Lessor, Lease, Description [Line Items]
Number of properties subject to ground leases | property	3
Operating lease, right-of-use assets	$ 29,104	$ 29,307
Ground lease liabilities	$ 29,104	$ 29,307
Weighted average discount rate (as a percent)	4.50%
Weighted average remaining lease term (in years)	49 years 3 months 18 days
Minimum
Lessor, Lease, Description [Line Items]
Term of contract, lessor (in years)	1 year
Maximum
Lessor, Lease, Description [Line Items]
Term of contract, lessor (in years)	21 years

Leases - Components of Rental R

Leases - Components of Rental Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Fixed payments	$ 496,515	$ 510,799
Variable payments	66,556	75,615
Total rental revenue	$ 563,071	$ 586,414

Leases - Future Contractual Min

Leases - Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received, Current Year (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 492,574
2022	489,185
2023	468,877
2024	431,204
2025	391,228
Thereafter	1,846,423
Total future minimum lease payments on non-cancellable operating leases to be received	$ 4,119,491

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments on Ground Leases, Current Year (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 1,518
2022	1,518
2023	1,518
2024	1,518
2025	1,518
Thereafter	65,262
Total undiscounted lease payments	72,852
Present value discount	(43,748)
Ground lease liabilities	$ 29,104	$ 29,307

Commitments and Contingencies -

Commitments and Contingencies - Litigation (Details) $ in Thousands	Aug. 26, 2020USD ($)	Oct. 31, 2014participant	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Loss Contingencies [Line Items]
IPO litigation expense				$ 1,165	$ 0	$ 0
New York State Supreme Court, New York County
Loss Contingencies [Line Items]
Number of plaintiffs opting out of settlement (participant) | participant		12
Amount awarded to claimants	$ 1,200
Interest period (in years)	7 years
IPO litigation expense			$ 1,200

Commitments and Contingencies_2

Commitments and Contingencies - Unfunded Capital Expenditures (Details) $ in Millions	Dec. 31, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Unfunded capital expenditures	$ 121.9

Commitments and Contingencies_3

Commitments and Contingencies - Major Customers and Other Concentrations (Details) - Customer concentration risk - Rental revenue - office_and_property	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Number of properties	6	6	6
Empire State Building
Concentration Risk [Line Items]
Concentration risk percentage	32.80%	32.90%	31.90%
One Grand Central Place
Concentration Risk [Line Items]
Concentration risk percentage	12.40%	12.30%	12.80%
111 West 33rd Street
Concentration Risk [Line Items]
Concentration risk percentage	10.50%	9.90%	9.30%
1400 Broadway
Concentration Risk [Line Items]
Concentration risk percentage	8.00%	7.10%	7.10%
First Stamford Place
Concentration Risk [Line Items]
Concentration risk percentage	5.70%	5.50%	5.20%
250 West 57th Street
Concentration Risk [Line Items]
Concentration risk percentage	5.40%	5.40%	5.90%
Tenant 1
Concentration Risk [Line Items]
Concentration risk percentage	6.90%	6.80%	6.00%
Tenant 2
Concentration Risk [Line Items]
Concentration risk percentage	3.50%	3.20%	3.10%
Tenant 3
Concentration Risk [Line Items]
Concentration risk percentage		3.20%	2.90%
Tenant 4
Concentration Risk [Line Items]
Concentration risk percentage			2.00%
Tenant 5
Concentration Risk [Line Items]
Concentration risk percentage			2.00%

Commitments and Contingencies_4

Commitments and Contingencies - Multiemployer Pension and Defined Contribution Plans Narrative (Details) - Building Service 32BJ - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Pension Plans
Multiemployer Plans [Line Items]
Plan contributions	$ 291.3	$ 290.1	$ 272.3
Health Plans
Multiemployer Plans [Line Items]
Plan contributions	$ 1,600	$ 1,500	$ 1,400

Commitments and Contingencies_5

Commitments and Contingencies - Schedule of Contributions made to Multiemployer Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plans [Line Items]
Contributions	$ 9,672	$ 14,114	$ 13,514
Pension Plans
Multiemployer Plans [Line Items]
Contributions	2,383	3,418	3,327
Contributions, insignificant	800	1,000	1,000
Health Plans
Multiemployer Plans [Line Items]
Contributions	6,873	10,055	9,373
Contributions, insignificant	1,400	1,800	1,600
Other
Multiemployer Plans [Line Items]
Contributions	416	641	814
Contributions, insignificant	$ 300	$ 400	$ 200

Capital - Shares and Units and

Capital - Shares and Units and Private Perpetual Preferred Units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	May 16, 2019
Shares and Units [Abstract]
OP units outstanding (in shares)	285,300,000
OP units owned by the Company (in shares)	171,600,000
OP units not owned by the Company (in shares)	113,700,000
Percentage of dividends on common stock received until performance criteria met for LTIP units	10.00%
Percentage of dividends on common stock received after performance criteria met for LTIP units	90.00%
Percentage of dividends on common stock received in periods after performance criteria met for LTIP units	100.00%
2019 Plan
Shares and Units [Abstract]
Number of shares authorized under the plan (in shares)	11,000,000		11,000,000
Empire State Realty OP | Empire State Realty Trust
Shares and Units [Abstract]
OP units owned by the Company (as a percent)	60.10%
Empire State Realty OP | Other partners, certain directors, member of senior management and other employees
Shares and Units [Abstract]
OP units not owned by the Company (as a percent)	39.90%
Private Perpetual Preferred Units, Series 2019
Shares and Units [Abstract]
Private perpetual preferred units, issued (in shares)	4,664,038	4,610,383
Private perpetual preferred units, liquidation preference per share (in dollars per share)	$ 13.52	$ 13.52
Cumulative cash distributions (in dollars per share)	$ 0.70
Private Perpetual Preferred Units, Series 2014
Shares and Units [Abstract]
Private perpetual preferred units, issued (in shares)	1,560,360	1,560,360
Private perpetual preferred units (in shares)	1,560,360
Private perpetual preferred units, liquidation preference per share (in dollars per share)	$ 16.62	$ 16.62
Dividend declared (in dollars per share)	$ 0.60

Capital - Equity Securities Rep

Capital - Equity Securities Repurchased (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 11, 2020	Dec. 31, 2019
Equity [Abstract]
Stock repurchase authorized amount		$ 500,000,000	$ 500,000,000
Total Number of Shares Purchased (in shares)	17,279,252
Average Price Paid Per Share (in dollars per share)	$ 8.32
Maximum Approximate Dollar Value Available for Future Purchase	$ 356,287,000

Capital - Distributions (Detail

Capital - Distributions (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Dividends declared and paid on operating partnership units (in dollars per share)	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105	$ 0.105
Distributions paid to OP unit holders											$ 65	$ 127.8	$ 126.5

Capital - Incentive and Share-b

Capital - Incentive and Share-based Compensation (Details) $ / shares in Units, $ in Millions

Jul. 13, 2020

Jun. 30, 2020USD ($)shares

May 31, 2020USD ($)vesting_installmentshares

Mar. 31, 2020USD ($)vesting_installmentshares

Mar. 31, 2019USD ($)vesting_installmentshares

Mar. 31, 2020

Dec. 31, 2020USD ($)shares

Jul. 12, 2020

Oct. 31, 2019USD ($)shares

Dec. 31, 2020USD ($)$ / sharesshares

Dec. 31, 2019USD ($)$ / shares

Dec. 31, 2018USD ($)$ / shares

May 16, 2019shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Retirement age (in years)

65 years

60 years

60 years

Expected volatility rate look-back period (in years)

6 years

Weighted-average per unit or share fair value (in dollars per share) | $ / shares

$ 5.44

Period of service, upon completion of which, grantee's LTIP unit and restricted stock awards will immediately vest (in years)

10 years

Awards that Meet Age and Service Requirements for Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Noncash share-based compensation expense recognized | $

$ 2.6

$ 2

$ 1.8

Unrecognized compensation expense | $

$ 1.4

$ 1.4

Unrecognized compensation expense, period for recognition (in years)

2 years 1 month 6 days

Awards that Do Not Meet Age and Service Requirements for Vesting

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Noncash share-based compensation expense recognized | $

$ 22.9

18.8

17

Unrecognized compensation expense | $

$ 26.5

$ 26.5

Unrecognized compensation expense, period for recognition (in years)

2 years 2 months 12 days

Long-Term Incentive Plan Units and Restricted Stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fair value of share-based awards granted in period | $

$ 28.3

$ 27.9

$ 23.6

Weighted-average per unit or share fair value (in dollars per share) | $ / shares

$ 5.44

$ 9.56

$ 8.54

Expected term (in terms)

2 years 9 months 18 days

Dividend rate (as a percent)

3.70%

2.40%

2.30%

Risk free interest rate, minimum (as a percent)

0.16%

Risk free interest rate, maximum (as a percent)

0.50%

Expected price volatility, minimum (as a percent)

19.00%

Expected price volatility, maximum (as a percent)

26.00%

Risk free interest rate (as a percent)

2.50%

Expected volatility rate (as a percent)

20.00%

Fair value vested in period | $

$ 15.6

$ 10.1

$ 7.7

Time Based Long-Tern Incentive Plan Unit

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Threshold of continuous service for retirement eligibility (in years)

10 years

Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

63,229

113,971

Fair value of share-based awards granted in period | $

$ 0.4

$ 2.3

Award vesting period (in years)

4 years

Number of vesting installments | vesting_installment

3

Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

61,432

Fair value of share-based awards granted in period | $

$ 2

Award vesting period (in years)

4 years

Number of vesting installments | vesting_installment

3

Market Based Long-Term Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

502,475

Fair value of share-based awards granted in period | $

$ 2.3

Award vesting period (in years)

3 years

3 years

Number of vesting installments | vesting_installment

2

2

Market Based Long-Term Incentive Plan Unit | 2013 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

113,383

Fair value of share-based awards granted in period | $

$ 0.9

Award vesting period (in years)

3 years

Number of vesting installments | vesting_installment

2

Time Restricted Shares | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

158,806

Time Restricted Shares | 2013 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

69,358

Director | Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

171,153

31,117

76,718

Fair value of share-based awards granted in period | $

$ 1.1

$ 0.2

$ 1.1

Award vesting period (in years)

3 years

Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

82,199

745,155

Fair value of share-based awards granted in period | $

$ 0.5

$ 5.6

Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units, Connected With Bonus Program

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

624,380

Fair value of share-based awards granted in period | $

$ 4.4

Award vesting period (in years)

3 years

Award vesting percentage of award face amount (as a percent)

125.00%

125.00%

Executive Officer | Time Based Long-Tern Incentive Plan Unit | Vest immediately

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

23,049

26,056

Executive Officer | Time Based Long-Tern Incentive Plan Unit | Vest over three years

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

601,331

308,896

Award vesting period (in years)

3 years

3 years

Executive Officer | Time Based Long-Tern Incentive Plan Unit | Vest in two equal installments

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of vesting installments | vesting_installment

2

2

Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

461,693

Fair value of share-based awards granted in period | $

$ 6.4

Executive Officer | Time Based Long-Tern Incentive Plan Unit | 2013 Plan Units, Connected With Bonus Program

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

334,952

Fair value of share-based awards granted in period | $

$ 4.6

Executive Officer | Market Based Long-Term Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

116,927

3,358,767

Fair value of share-based awards granted in period | $

$ 0.5

$ 14

Reduction of grants (in shares) | shares

666,933

Fair value of reduction of share-based awards granted in period | $

$ 2.8

Executive Officer | Market Based Long-Term Incentive Plan Unit | 2013 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares granted (in shares) | shares

1,806,520

Fair value of share-based awards granted in period | $

$ 12.8

Certain Other Employees | Market Based Long-Term Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reduction of grants (in shares) | shares

99,630

Fair value of reduction of share-based awards granted in period | $

$ 0.5

2019 Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of shares authorized under the plan (in shares) | shares

11,000,000

11,000,000

11,000,000

Number of shares that remain available for future issuance (in shares) | shares

8,500,000

8,500,000

Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Age of grantee at which LTIP unit and restricted stock awards immediately vest (in years)

60 years

Minimum | Long-Term Incentive Plan Units and Restricted Stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected term (in terms)

2 years

2 years

Risk free interest rate (as a percent)

2.48%

Expected volatility rate (as a percent)

17.00%

Minimum | Time Based Long-Tern Incentive Plan Unit

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award vesting period (in years)

3 years

Minimum | Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award vesting period (in years)

3 years

Number of vesting installments | vesting_installment

2

Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Age of grantee at which LTIP unit and restricted stock awards immediately vest (in years)

65 years

Maximum | Long-Term Incentive Plan Units and Restricted Stock

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected term (in terms)

5 years 6 months

5 years 3 months 18 days

Risk free interest rate (as a percent)

2.63%

Expected volatility rate (as a percent)

22.00%

Maximum | Time Based Long-Tern Incentive Plan Unit

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award vesting period (in years)

4 years

Maximum | Time Based Long-Tern Incentive Plan Unit | 2019 Plan Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award vesting period (in years)

4 years

Number of vesting installments | vesting_installment

3

Capital - Summary of ESRT restr

Capital - Summary of ESRT restricted stock and LTIP unit activity (Details)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Weighted Average Grant Fair Value
Unvested, beginning balance (in dollars per share) | $ / shares	$ 9.73
Vested (in dollars per share) | $ / shares	14.04
Granted (in dollars per share) | $ / shares	5.44
Forfeited or unearned (in dollars per share) | $ / shares	7.55
Unvested, ending balance (in dollars per share) | $ / shares	$ 6.94
Restricted Stock
Restricted Stock and LTIP Units
Unvested, beginning balance (in shares)	118,918
Vested (in shares)	(58,326)
Granted (in shares)	161,449
Forfeited or unearned (in shares)	(4,341)
Unvested, ending balance (in shares)	217,700
Long-Term Incentive Plan Unit
Restricted Stock and LTIP Units
Unvested, beginning balance (in shares)	5,986,569
Vested (in shares)	(1,052,692)
Granted (in shares)	5,042,810
Forfeited or unearned (in shares)	(2,226,403)
Unvested, ending balance (in shares)	7,750,284

Capital - Earnings Per Unit (De

Capital - Earnings Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income	$ 710	$ (12,269)	$ (19,618)	$ 8,288	$ 28,720	$ 26,784	$ 18,930	$ 9,856	$ 39,781	$ 29,230	$ 30,184	$ 18,058	$ (22,889)	$ 84,290	$ 117,253
Private perpetual preferred unit distributions													(4,197)	(1,743)	(936)
Earnings allocated to unvested shares													(985)	(885)	(851)
Net income (loss) attributable to common unitholders - basic and diluted													$ (28,071)	$ 81,662	$ 115,466
Denominator:
Weighted average units outstanding - basic and diluted (in shares)													283,826,000	297,798,000	297,258,000
Effect of dilutive securities, stock-based compensation plans (in shares)													11,000	0	1,000
Weighted average shares outstanding - diluted (in shares)													283,837,000	297,798,000	297,259,000
Earnings per unit - basic and diluted (in dollars per share)	$ 0	$ (0.05)	$ (0.07)	$ 0.02	$ 0.09	$ 0.09	$ 0.06	$ 0.03	$ 0.13	$ 0.10	$ 0.10	$ 0.06	$ (0.10)	$ 0.27	$ 0.39
Antidilutive shares and LTIP units (in shares)													307,536	416,492	485,865

Related Party Transactions - Ta

Related Party Transactions - Tax Protection Agreements (Details) $ in Millions	Oct. 07, 2013USD ($)	Dec. 31, 2013property	Aug. 23, 2016
Malkin Group
Related Party Transaction [Line Items]
Number of properties protected | property		4
Aggregate number of operating partnership units and common stock threshold during tax protection period	50.00%
Bottom dollar guarantee of aggregate indebtedness during tax protection period | $	$ 160
Q REIT Holding LLC
Related Party Transaction [Line Items]
Threshold to indemnify			10.00%

Related Party Transactions - Re

Related Party Transactions - Registration Rights (Details) - Registration rights agreement	12 Months Ended
	Dec. 31, 2020USD ($)underwritten_offering
Related Party Transaction [Line Items]
Number of underwritten offerings, maximum, during 12-month period following shelf effective date | underwritten_offering	2
Primary shares cutback value, minimum	$ 25,000,000
Payments for fees and registration per underwritten offering, maximum	25,000
Certain persons receiving common stock or operating partnership units in formation transactions
Related Party Transaction [Line Items]
Registrable shares market value, minimum	$ 150,000,000
Number of underwritten offerings, maximum | underwritten_offering	4

Related Party Transactions - Ex

Related Party Transactions - Excluded Properties and Businesses (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)office_and_propertyinterestproperty	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Retail | Manhattan
Related Party Transaction [Line Items]
Number of properties | office_and_property	4
Office Building
Related Party Transaction [Line Items]
Number of properties | office_and_property	14
Office Building | Manhattan
Related Party Transaction [Line Items]
Number of properties | office_and_property	9
Malkin Group | Mezzanine and Senior Equity Funds
Related Party Transaction [Line Items]
Number of interests owned | interest	1
Malkin Group | Residential Property Manager
Related Party Transaction [Line Items]
Number of properties | interest	5
Number of interests owned | interest	5
Malkin Group | Multi-family Property | Greenwich, Connecticut
Related Party Transaction [Line Items]
Number of properties	9
Malkin Group | Retail | Greenwich, Connecticut
Related Party Transaction [Line Items]
Number of properties	5
Malkin Group | Retail | Manhattan
Related Party Transaction [Line Items]
Number of properties	2
Malkin Group | Former Post Office | Greenwich, Connecticut
Related Party Transaction [Line Items]
Number of properties	1
Malkin Group | Office Building | Manhattan
Related Party Transaction [Line Items]
Number of properties	1
Supervisory fee revenue | Third party management and other fees | Affiliated Entity
Related Party Transaction [Line Items]
Revenue from related parties | $	$ 0.9	$ 0.9	$ 1.1
Property management fee revenue | Third party management and other fees | Affiliated Entity
Related Party Transaction [Line Items]
Revenue from related parties | $	$ 0.3	$ 0.3	$ 0.3

Related Party Transactions - Ot

Related Party Transactions - Other (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)ft²property	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Area of real estate property (in sqft)	10,100,000
Undivided Interest
Related Party Transaction [Line Items]
Area of real estate property (in sqft)	5,447
Chairman emeritus | Leased space rental
Related Party Transaction [Line Items]
Number of properties | property	1
Lease cancellation, period of notice (in days)	90 days
Percentage of lease space occupied by Chairman emeritus and employee	15.00%
Revenue from related parties, net of payment for pro rata share of leased space | $	$ 0.3	$ 0.3	$ 0.3

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 4,932	$ (1,077)	$ (2,389)
State and local	2,699	(872)	(2,253)
Total current	7,631	(1,949)	(4,642)
Deferred:
Federal	(340)	(248)	0
State and local	(320)	(232)	0
Total deferred	(660)	(480)	0
Income tax benefit (expense)	$ 6,971	$ (2,429)	$ (4,642)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Effective income tax rate (as a percent)	47.00%	34.00%	34.00%
Valuation allowance	$ 0	$ 0	$ 0
Unrecognized tax benefits	0	$ 0	$ 0
Empire State Realty Trust
Operating Loss Carryforwards [Line Items]
NOL carryforwards	$ 67,900,000
Observatory | Operating Segments
Operating Loss Carryforwards [Line Items]
Increase of U.S. corporation income tax benefit as a result of NOL carryback from CARES Act (as a percent)	13.00%
NOL carryforwards	$ 3,800,000
Income tax receivable	$ 8,100,000

Income Taxes - Schedule of Actu

Income Taxes - Schedule of Actual Tax Provision Differed From Federal Statutory Corporate Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal tax benefit (expense) at statutory rate	$ 2,544	$ (1,575)	$ (2,844)
State income tax benefit (expense), net of federal benefit	2,379	(854)	(1,798)
Corporate income tax rate adjustment	2,048	0	0
Income tax benefit (expense)	$ 6,971	$ (2,429)	$ (4,642)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Deferred revenue on unredeemed observatory admission ticket sales	$ 256	$ 916	$ 1,396
New York City net operating loss carryforward credit	334	0	0
Deferred tax assets	$ 590	$ 916	$ 1,396

Segment Reporting - Narrative (

Segment Reporting - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Impairment charges			$ 6,204	$ 0	$ 0
Real Estate
Segment Reporting Information [Line Items]
Impairment charges	$ 2,100	$ 4,100	$ 6,200

Segment Reporting - Segment Rev

Segment Reporting - Segment Revenue and Profit or Loss Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Rental revenue													$ 563,071	$ 586,414
Rental revenue															$ 493,231
Intercompany rental revenue													0	0	0
Tenant expense reimbursement													0	0	72,372
Observatory revenue													29,057	128,769	131,227
Lease termination fees													9,416	4,352	20,847
Third-party management and other fees													1,225	1,254	1,440
Other revenue and fees													6,459	10,554	12,394
Total revenues	$ 151,399	$ 146,575	$ 141,030	$ 170,224	$ 194,933	$ 192,873	$ 176,244	$ 167,293	$ 199,309	$ 186,402	$ 178,529	$ 167,271	609,228	731,343	731,511
Operating expenses:
Property operating expenses													136,141	174,977	167,379
Intercompany rent expense													0	0	0
Ground rent expense													9,326	9,326	9,326
General and administrative expenses													62,244	61,063	52,674
Observatory expenses													23,723	33,767	32,767
Real estate taxes													121,923	115,916	110,000
Impairment charges													6,204	0	0
Depreciation and amortization													191,006	181,588	168,508
Total operating expenses													550,567	576,637	540,654
Total operating income	19,426	11,928	334	26,973	47,112	45,279	36,239	26,076	58,490	48,538	49,665	34,164	58,661	154,706	190,857
Other income (expense):
Interest income													2,637	11,259	10,661
Interest expense													(89,907)	(79,246)	(79,623)
Loss on early extinguishment of debt													(86)	0	0
IPO litigation expense													(1,165)	0	0
Income (loss) before income taxes													(29,860)	86,719	121,895
Income tax benefit (expense)													6,971	(2,429)	(4,642)
Net income (loss)	710	(12,269)	(19,618)	$ 8,288	28,720	$ 26,784	$ 18,930	$ 9,856	39,781	$ 29,230	$ 30,184	$ 18,058	(22,889)	84,290	117,253
Segment assets	4,150,695				3,931,834				4,195,780				4,150,695	3,931,834	4,195,780
Expenditures for segment assets													104,060	255,924	256,496
Intersegment Elimination
Revenues:
Intercompany rental revenue													(17,827)	(82,469)	(79,954)
Observatory revenue															0
Total revenues													(17,827)	(82,469)	(79,954)
Operating expenses:
Intercompany rent expense													(17,827)	(82,469)	(79,954)
General and administrative expenses													0	0	0
Impairment charges													0
Depreciation and amortization													0	0	0
Total operating expenses													(17,827)	(82,469)	(79,954)
Total operating income													0	0	0
Other income (expense):
Interest income													0	0	0
Interest expense													0	0	0
Loss on early extinguishment of debt													0
IPO litigation expense													0
Income (loss) before income taxes													0	0	0
Income tax benefit (expense)													0	0	0
Net income (loss)													0	0	0
Segment assets	0				0				0				0	0	0
Expenditures for segment assets													0	0	0
Real Estate
Operating expenses:
Impairment charges		$ 2,100	$ 4,100										6,200
Real Estate | Operating Segments
Revenues:
Rental revenue													563,071	586,414
Rental revenue															493,231
Intercompany rental revenue													17,827	82,469	79,954
Tenant expense reimbursement															72,372
Observatory revenue															0
Lease termination fees													9,416	4,352	20,847
Third-party management and other fees													1,225	1,254	1,440
Other revenue and fees													6,459	10,554	12,394
Total revenues													597,998	685,043	680,238
Operating expenses:
Property operating expenses													136,141	174,977	167,379
Intercompany rent expense													0	0	0
Ground rent expense													9,326	9,326	9,326
General and administrative expenses													62,244	61,063	52,674
Real estate taxes													121,923	115,916	110,000
Impairment charges													6,204
Depreciation and amortization													190,863	181,558	168,430
Total operating expenses													526,701	542,840	507,809
Total operating income													71,297	142,203	172,429
Other income (expense):
Interest income													2,542	11,259	10,661
Interest expense													(89,907)	(79,246)	(79,623)
Loss on early extinguishment of debt													(86)
IPO litigation expense													(1,165)
Income (loss) before income taxes													(17,319)	74,216	103,467
Income tax benefit (expense)													(843)	(896)	(1,114)
Net income (loss)													(18,162)	73,320	102,353
Segment assets	3,903,884				3,671,211				3,930,330				3,903,884	3,671,211	3,930,330
Expenditures for segment assets													101,306	191,630	201,685
Observatory | Operating Segments
Revenues:
Intercompany rental revenue													0	0	0
Observatory revenue													29,057	128,769	131,227
Total revenues													29,057	128,769	131,227
Operating expenses:
Intercompany rent expense													17,827	82,469	79,954
General and administrative expenses													0	0	0
Observatory expenses													23,723	33,767	32,767
Impairment charges													0
Depreciation and amortization													143	30	78
Total operating expenses													41,693	116,266	112,799
Total operating income													(12,636)	12,503	18,428
Other income (expense):
Interest income													95	0	0
Interest expense													0	0	0
Loss on early extinguishment of debt													0
IPO litigation expense													0
Income (loss) before income taxes													(12,541)	12,503	18,428
Income tax benefit (expense)													7,814	(1,533)	(3,528)
Net income (loss)													(4,727)	10,970	14,900
Segment assets	$ 246,811				$ 260,623				$ 265,450				246,811	260,623	265,450
Expenditures for segment assets													$ 2,754	$ 64,294	$ 54,811

Summary of Quarterly Financia_3

Summary of Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 151,399	$ 146,575	$ 141,030	$ 170,224	$ 194,933	$ 192,873	$ 176,244	$ 167,293	$ 199,309	$ 186,402	$ 178,529	$ 167,271	$ 609,228	$ 731,343	$ 731,511
Operating income	19,426	11,928	334	26,973	47,112	45,279	36,239	26,076	58,490	48,538	49,665	34,164	58,661	154,706	190,857
Net income (loss)	710	(12,269)	(19,618)	8,288	28,720	26,784	18,930	9,856	39,781	29,230	30,184	18,058	$ (22,889)	$ 84,290	$ 117,253
Net income (loss) attributable to common stockholders	$ (340)	$ (13,319)	$ (20,665)	$ 7,238	$ 27,679	$ 26,550	$ 18,696	$ 9,622	$ 39,547	$ 28,996	$ 29,950	$ 17,824
Basic and diluted net income per share attributable to common unitholders (in dollars per share)	$ 0	$ (0.05)	$ (0.07)	$ 0.02	$ 0.09	$ 0.09	$ 0.06	$ 0.03	$ 0.13	$ 0.10	$ 0.10	$ 0.06	$ (0.10)	$ 0.27	$ 0.39

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance At Beginning of Year	$ 1,607
Additions Charged Against Operations	(811)
Uncollectible Accounts Written-Off	(289)
Balance at End of Year	$ 507

Schedule III - Real Estate an_2

Schedule III - Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 775,929
Initial Cost to the Company
Land and Development Costs	199,287
Building & Improvements	918,018
Cost Capitalized Subsequent to Acquisition
Improvements	2,016,661
Gross Amount at which Carried
Land and Development Costs	209,162
Buildings & Improvements	2,924,804
Total	3,133,966	$ 3,109,433	$ 2,884,486	$ 2,667,655
Accumulated Depreciation	941,612	$ 862,534	$ 747,304	$ 656,900
111 West 33rd Street, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	13,630
Building & Improvements	244,461
Cost Capitalized Subsequent to Acquisition
Improvements	125,514
Gross Amount at which Carried
Land and Development Costs	13,630
Buildings & Improvements	369,975
Total	383,605
Accumulated Depreciation	70,495
1400 Broadway | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	0
Building & Improvements	96,338
Cost Capitalized Subsequent to Acquisition
Improvements	86,939
Gross Amount at which Carried
Land and Development Costs	0
Buildings & Improvements	183,277
Total	183,277
Accumulated Depreciation	46,694
1333 Broadway, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	158,676
Initial Cost to the Company
Land and Development Costs	91,435
Building & Improvements	120,190
Cost Capitalized Subsequent to Acquisition
Improvements	10,469
Gross Amount at which Carried
Land and Development Costs	91,435
Buildings & Improvements	130,659
Total	222,094
Accumulated Depreciation	29,285
1350 Broadway, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	0
Building & Improvements	102,518
Cost Capitalized Subsequent to Acquisition
Improvements	38,180
Gross Amount at which Carried
Land and Development Costs	0
Buildings & Improvements	140,698
Total	140,698
Accumulated Depreciation	38,967
250 West 57th Street, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	173,835
Initial Cost to the Company
Land and Development Costs	2,117
Building & Improvements	5,041
Cost Capitalized Subsequent to Acquisition
Improvements	163,843
Gross Amount at which Carried
Land and Development Costs	2,117
Buildings & Improvements	168,884
Total	171,001
Accumulated Depreciation	49,958
501 Seventh Avenue, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	1,100
Building & Improvements	2,600
Cost Capitalized Subsequent to Acquisition
Improvements	96,842
Gross Amount at which Carried
Land and Development Costs	1,100
Buildings & Improvements	99,442
Total	100,542
Accumulated Depreciation	45,220
1359 Broadway, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	1,233
Building & Improvements	1,809
Cost Capitalized Subsequent to Acquisition
Improvements	63,075
Gross Amount at which Carried
Land and Development Costs	1,233
Buildings & Improvements	64,884
Total	66,117
Accumulated Depreciation	32,420
350 Fifth Avenue (Empire State Building), New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	21,551
Building & Improvements	38,934
Cost Capitalized Subsequent to Acquisition
Improvements	970,966
Gross Amount at which Carried
Land and Development Costs	21,551
Buildings & Improvements	1,009,900
Total	1,031,451
Accumulated Depreciation	275,648
One Grand Central Place, New York, NY | office/ retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	7,240
Building & Improvements	17,490
Cost Capitalized Subsequent to Acquisition
Improvements	268,333
Gross Amount at which Carried
Land and Development Costs	7,222
Buildings & Improvements	285,841
Total	293,063
Accumulated Depreciation	123,509
First Stamford Place, Stamford, CT | office
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	178,943
Initial Cost to the Company
Land and Development Costs	22,952
Building & Improvements	122,739
Cost Capitalized Subsequent to Acquisition
Improvements	75,458
Gross Amount at which Carried
Land and Development Costs	24,861
Buildings & Improvements	196,288
Total	221,149
Accumulated Depreciation	91,678
One Station Place, Stamford, CT (Metro Center) | office
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	87,236
Initial Cost to the Company
Land and Development Costs	5,313
Building & Improvements	28,602
Cost Capitalized Subsequent to Acquisition
Improvements	19,581
Gross Amount at which Carried
Land and Development Costs	5,313
Buildings & Improvements	48,183
Total	53,496
Accumulated Depreciation	31,903
383 Main Avenue, Norwalk, CT | office
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	29,668
Initial Cost to the Company
Land and Development Costs	2,262
Building & Improvements	12,820
Cost Capitalized Subsequent to Acquisition
Improvements	30,878
Gross Amount at which Carried
Land and Development Costs	2,262
Buildings & Improvements	43,698
Total	45,960
Accumulated Depreciation	15,901
500 Mamaroneck Avenue, Harrison, NY | office
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	4,571
Building & Improvements	25,915
Cost Capitalized Subsequent to Acquisition
Improvements	26,708
Gross Amount at which Carried
Land and Development Costs	4,571
Buildings & Improvements	52,623
Total	57,194
Accumulated Depreciation	26,760
10 Bank Street, White Plains, NY | office
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	31,624
Initial Cost to the Company
Land and Development Costs	5,612
Building & Improvements	31,803
Cost Capitalized Subsequent to Acquisition
Improvements	20,833
Gross Amount at which Carried
Land and Development Costs	5,612
Buildings & Improvements	52,636
Total	58,248
Accumulated Depreciation	25,537
10 Union Square, New York, NY | retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	49,365
Initial Cost to the Company
Land and Development Costs	5,003
Building & Improvements	12,866
Cost Capitalized Subsequent to Acquisition
Improvements	2,579
Gross Amount at which Carried
Land and Development Costs	5,003
Buildings & Improvements	15,445
Total	20,448
Accumulated Depreciation	8,687
1542 Third Avenue, New York, NY | retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	29,592
Initial Cost to the Company
Land and Development Costs	2,239
Building & Improvements	15,266
Cost Capitalized Subsequent to Acquisition
Improvements	464
Gross Amount at which Carried
Land and Development Costs	2,239
Buildings & Improvements	15,730
Total	17,969
Accumulated Depreciation	8,644
1010 Third Avenue, New York, NY and 77 West 55th Street, New York, NY | retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	36,990
Initial Cost to the Company
Land and Development Costs	4,462
Building & Improvements	15,817
Cost Capitalized Subsequent to Acquisition
Improvements	1,251
Gross Amount at which Carried
Land and Development Costs	4,463
Buildings & Improvements	17,067
Total	21,530
Accumulated Depreciation	9,500
69-97 Main Street, Westport, CT | retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	2,782
Building & Improvements	15,766
Cost Capitalized Subsequent to Acquisition
Improvements	6,317
Gross Amount at which Carried
Land and Development Costs	2,782
Buildings & Improvements	22,083
Total	24,865
Accumulated Depreciation	8,052
103-107 Main Street, Westport, CT | retail
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	1,243
Building & Improvements	7,043
Cost Capitalized Subsequent to Acquisition
Improvements	360
Gross Amount at which Carried
Land and Development Costs	1,260
Buildings & Improvements	7,386
Total	8,646
Accumulated Depreciation	2,754
Property for development at the Transportation Hub in Stamford, CT | land
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost to the Company
Land and Development Costs	4,542
Building & Improvements	0
Cost Capitalized Subsequent to Acquisition
Improvements	8,071
Gross Amount at which Carried
Land and Development Costs	12,508
Buildings & Improvements	105
Total	12,613
Accumulated Depreciation	$ 0

Schedule III - Real Estate an_3

Schedule III - Real Estate and Accumulated Depreciation Reconciliation of Investment Properties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Balance, beginning of year	$ 3,109,433	$ 2,884,486	$ 2,667,655
Acquisition of new properties	0	0	0
Improvements	104,060	255,924	256,496
Disposals	(79,527)	(30,977)	(39,665)
Balance, end of year	3,133,966	$ 3,109,433	$ 2,884,486
Aggregate cost of investment properties for federal income tax purpose	$ 2,800,000

Schedule III - Real Estate an_4

Schedule III - Real Estate and Accumulated Depreciation Reconciliation of Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward]
Balance, beginning of year	$ 862,534	$ 747,304	$ 656,900
Depreciation expense	158,605	146,207	130,069
Disposals	(79,527)	(30,977)	(39,665)
Balance, end of year	$ 941,612	$ 862,534	$ 747,304

Schedule III - Real Estate an_5

Schedule III - Real Estate and Accumulated Depreciation Schedule of Estimated Useful Lives of Investment Properties (Details)	12 Months Ended
	Dec. 31, 2020
Buildings
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Estimated original useful lives (in years)	39 years
Building improvements
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Estimated original useful lives (in years)	39 years

Uncategorized Items - esrt-2020

Label	Element	Value
Derivative Financial Instruments Included in Accounts Payable and Accrued Expense	esrt_DerivativeFinancialInstrumentsIncludedinAccountsPayableandAccruedExpense	$ 13,330,000
Derivative Financial Instruments Included in Accounts Payable and Accrued Expense	esrt_DerivativeFinancialInstrumentsIncludedinAccountsPayableandAccruedExpense	8,849,000
Derivative Financial Instruments Included in Accounts Payable and Accrued Expense	esrt_DerivativeFinancialInstrumentsIncludedinAccountsPayableandAccruedExpense	5,243,000
Derivative Financial Instruments Included in Prepaid Expenses and Other Assets	esrt_DerivativeFinancialInstrumentsIncludedinPrepaidExpensesandOtherAssets	0
Derivative Financial Instruments Included in Prepaid Expenses and Other Assets	esrt_DerivativeFinancialInstrumentsIncludedinPrepaidExpensesandOtherAssets	0
Derivative Financial Instruments Included in Prepaid Expenses and Other Assets	esrt_DerivativeFinancialInstrumentsIncludedinPrepaidExpensesandOtherAssets	$ 2,536,000