Empire State Realty OP (FISK) 10-Q 5 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001553079
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Series ES operating partnership units
Title of 12(b) Security	Series ES operating partnership units
Trading Symbol	ESBA
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		23,961,924
Series 60 operating partnership units
Title of 12(b) Security	Series 60 operating partnership units
Trading Symbol	OGCP
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		6,581,181
Series 250 operating partnership units
Title of 12(b) Security	Series 250 operating partnership units
Trading Symbol	FISK
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		3,350,293

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Commercial real estate properties, at cost:
Land	$ 201,196	$ 201,196
Development costs	7,938	7,989
Building and improvements	2,925,532	2,900,248
Commercial real estate properties, at cost	3,134,666	3,109,433
Less: accumulated depreciation	(927,517)	(862,534)
Commercial real estate properties, net	2,207,149	2,246,899
Cash and cash equivalents	373,088	233,946
Restricted cash	54,865	37,651
Tenant and other receivables	25,853	25,423
Deferred rent receivables	223,886	220,960
Prepaid expenses and other assets	50,773	65,453
Deferred costs, net	207,774	228,150
Acquired below-market ground leases, net	346,693	352,566
Right of use assets	29,154	29,307
Goodwill	491,479	491,479
Total assets	4,010,714	3,931,834
Liabilities:
Mortgage notes payable, net	603,178	605,542
Senior unsecured notes, net	973,106	798,392
Unsecured term loan facilities, net	387,309	264,640
Unsecured revolving credit facility, net	0	0
Accounts payable and accrued expenses	111,918	143,786
Acquired below-market leases, net	33,405	39,679
Ground lease liabilities	29,154	29,307
Deferred revenue and other liabilities	77,572	72,015
Tenants’ security deposits	51,257	30,560
Total liabilities	2,266,899	1,983,921
Commitments and contingencies
Capital:
Total capital	1,743,815	1,947,913
Total liabilities and capital	4,010,714	3,931,834
Private Perpetual Preferred Units, Series 2019
Capital:
Private perpetual preferred units	21,936	21,147
Private Perpetual Preferred Units, Series 2014
Capital:
Private perpetual preferred units	8,004	8,004
Series PR Operating Partnership Units
Capital:
ESRT partner's capital (2,883,759 and 2,996,520 general partner operating partnership units and 170,108,330 and 178,897,876 limited partner operating partnership units outstanding in 2020 and 2019, respectively)	1,069,269	1,228,520
Limited partner operating partnership units	647,465	680,580
Series ES operating partnership units
Capital:
Limited partner operating partnership units	(1,637)	7,262
Series 60 operating partnership units
Capital:
Limited partner operating partnership units	(819)	1,593
Series 250 operating partnership units
Capital:
Limited partner operating partnership units	$ (403)	$ 807

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Private Perpetual Preferred Units, Series 2019
Capital
Private perpetual preferred units, liquidation preference (in USD 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 (in USD 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)	81,140,140	81,387,763
Series ES operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	24,253,763	25,809,604
Series 60 operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	6,639,664	7,025,089
Series 250 operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	3,350,293	3,535,197
ESRT | Series PR Operating Partnership Units
Capital
General partner operating partnership units, outstanding (in shares)	2,883,759	2,996,520
Limited partner operating partnership units, outstanding (in shares)	170,108,330	178,897,876

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Rental revenue	$ 139,909	$ 150,225	$ 426,021	$ 434,713
Observatory revenue	4,419	37,575	24,049	91,039
Lease termination fees	331	2,361	1,575	3,112
Third-party management and other fees	283	304	930	955
Other revenue and fees	1,633	2,408	5,254	6,591
Total revenues	146,575	192,873	457,829	536,410
Operating expenses:
Property operating expenses	33,836	47,894	105,054	131,076
Ground rent expenses	2,331	2,331	6,994	6,994
General and administrative expenses	14,517	14,421	48,617	44,445
Observatory expenses	5,931	9,089	18,087	25,024
Real estate taxes	31,196	29,599	90,029	86,098
Impairment charges	2,103	0	6,204	0
Depreciation and amortization	44,733	44,260	143,609	135,179
Total operating expenses	134,647	147,594	418,594	428,816
Total operating income	11,928	45,279	39,235	107,594
Other income (expense):
Interest income	366	2,269	2,529	9,907
Interest expense	(23,360)	(19,426)	(66,906)	(60,712)
Loss on early extinguishment of debt	0	0	(86)	0
IPO litigation expense	(1,165)	0	(1,165)	0
Income (loss) before income taxes	(12,231)	28,122	(26,393)	56,789
Income tax benefit (expense)	(38)	(1,338)	2,794	(1,219)
Net income (loss)	(12,269)	26,784	(23,599)	55,570
Private perpetual preferred unit distributions	(1,050)	(234)	(3,147)	(702)
Net income (loss) attributable to common unitholders	$ (13,319)	$ 26,550	$ (26,746)	$ 54,868
Total weighted average units:
Basic (in units)	280,940	298,151	285,640	298,117
Diluted (in units)	280,940	298,151	285,640	298,117
Earnings per unit attributable to common unitholders:
Basic (in USD per unit)	$ (0.05)	$ 0.09	$ (0.10)	$ 0.18
Diluted (in USD per unit)	(0.05)	0.09	(0.10)	0.18
Dividends per unit (in USD per unit)	$ 0	$ 0.105	$ 0.210	$ 0.315

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (12,269)	$ 26,784	$ (23,599)	$ 55,570
Other comprehensive income (loss):
Unrealized gain (loss) on valuation of interest rate swap agreements	64	(6,256)	(19,340)	(25,992)
Less: amount reclassified into interest expense	2,873	319	5,986	637
Other comprehensive income (loss)	2,937	(5,937)	(13,354)	(25,355)
Comprehensive income (loss)	$ (9,332)	$ 20,847	$ (36,953)	$ 30,215

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Capital - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2020	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance		$ 1,756,038	$ 1,756,038	$ 1,948,032	$ 1,947,913	$ 1,991,109
Issuance of private perpetual preferred in exchange for common units					0
Conversion of operating partnership units to ESRT Partner's Capital			0	0	0	0
Repurchases of common units (in units)	(477,620)	(656,318)
Repurchases of common units			(7,345)		(121,950)
Equity compensation			5,504	3,647	20,174	15,392
Distributions			(1,050)	(32,180)	(65,369)	(96,370)
Net income (loss)			(12,269)	26,784	(23,599)	55,570
Other comprehensive income (loss)			2,937	(5,937)	(13,354)	(25,355)
Ending balance	$ 1,743,815		$ 1,743,815	$ 1,940,346	$ 1,743,815	$ 1,940,346
General Partner | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		173,347,000	173,347,000	178,021,000	181,894,000	174,912,000
Beginning balance		$ 1,080,221	$ 1,080,221	$ 1,215,647	$ 1,228,520	$ 1,238,482
Conversion of operating partnership units to ESRT Partner's Capital (in units)			779,000	2,130,000	5,155,000	5,185,000
Conversion of operating partnership units to ESRT Partner's Capital			$ 2,386	$ 12,796	$ 23,903	$ 21,654
Repurchases of common units (in units)			(1,134,000)		(14,205,000)
Repurchases of common units			$ (7,345)		$ (121,950)
Equity compensation (in units)				(1,000)	148,000	53,000
Equity compensation			334	$ 191	$ 719	$ 421
Distributions				(18,907)	(37,181)	(56,098)
Net income (loss)			(8,204)	15,882	(16,502)	32,646
Other comprehensive income (loss)			$ 1,877	$ (3,590)	$ (8,240)	$ (15,086)
Ending balance (in units)	172,992,000		172,992,000	180,150,000	172,992,000	180,150,000
Ending balance	$ 1,069,269		$ 1,069,269	$ 1,222,019	$ 1,069,269	$ 1,222,019
Limited Partners | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		82,766,000	82,766,000	86,749,000	81,388,000	86,202,000
Beginning balance		$ 647,520	$ 647,520	$ 713,039	$ 680,580	$ 725,108
Issuance of private perpetual preferred in exchange for common units (in units)					(97,000)
Issuance of private perpetual preferred in exchange for common units					$ (800)
Conversion of operating partnership units to ESRT Partner's Capital (in units)			(313,000)	(1,554,000)	(2,986,000)	(2,517,000)
Conversion of operating partnership units to ESRT Partner's Capital			$ (2,435)	$ (12,672)	$ (23,726)	$ (20,655)
Equity compensation (in units)			(1,313,000)	(634,000)	2,835,000	876,000
Equity compensation			$ 5,170	$ 3,456	$ 19,455	$ 14,971
Distributions				(8,880)	(17,619)	(26,884)
Net income (loss)			(3,490)	7,114	(6,954)	14,760
Other comprehensive income (loss)			$ 700	$ (1,578)	$ (3,471)	$ (6,821)
Ending balance (in units)	81,140,000		81,140,000	84,561,000	81,140,000	84,561,000
Ending balance	$ 647,465		$ 647,465	$ 700,479	$ 647,465	$ 700,479
Limited Partners | Series ES Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		24,529,000	24,529,000	28,518,000	25,810,000	30,129,000
Beginning balance		$ (770)	$ (770)	$ 8,508	$ 7,262	$ 14,399
Issuance of private perpetual preferred in exchange for common units (in units)					43,000
Issuance of private perpetual preferred in exchange for common units					$ 11
Conversion of operating partnership units to ESRT Partner's Capital (in units)			(275,000)	(358,000)	(1,599,000)	(1,969,000)
Conversion of operating partnership units to ESRT Partner's Capital			$ 23	$ (85)	$ (157)	$ (788)
Distributions				(2,960)	(5,264)	(9,020)
Net income (loss)			(1,145)	2,547	(2,327)	5,322
Other comprehensive income (loss)			$ 255	$ (556)	$ (1,162)	$ (2,459)
Ending balance (in units)	24,254,000		24,254,000	28,160,000	24,254,000	28,160,000
Ending balance	$ (1,637)		$ (1,637)	$ 7,454	$ (1,637)	$ 7,454
Limited Partners | Series 60 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		6,776,000	6,776,000	7,686,000	7,025,000	8,020,000
Beginning balance		$ (588)	$ (588)	$ 1,871	$ 1,593	$ 3,385
Conversion of operating partnership units to ESRT Partner's Capital (in units)			(136,000)	(142,000)	(385,000)	(476,000)
Conversion of operating partnership units to ESRT Partner's Capital			$ 19	$ (25)	$ (14)	$ (143)
Distributions				(794)	(1,435)	(2,431)
Net income (loss)			(320)	662	(642)	1,427
Other comprehensive income (loss)			$ 70	$ (135)	$ (321)	$ (659)
Ending balance (in units)	6,640,000		6,640,000	7,544,000	6,640,000	7,544,000
Ending balance	$ (819)		$ (819)	$ 1,579	$ (819)	$ 1,579
Limited Partners | Series 250 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		3,405,000	3,405,000	3,917,000	3,535,000	4,064,000
Beginning balance		$ (285)	$ (285)	$ 963	$ 807	$ 1,731
Conversion of operating partnership units to ESRT Partner's Capital (in units)			(55,000)	(75,000)	(185,000)	(222,000)
Conversion of operating partnership units to ESRT Partner's Capital			$ 7	$ (14)	$ (6)	$ (68)
Distributions				(405)	(723)	(1,235)
Net income (loss)			(160)	345	(321)	713
Other comprehensive income (loss)			$ 35	$ (78)	$ (160)	$ (330)
Ending balance (in units)	3,350,000		3,350,000	3,842,000	3,350,000	3,842,000
Ending balance	$ (403)		$ (403)	$ 811	$ (403)	$ 811
Private Perpetual Preferred Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		6,224,000	6,224,000	1,560,000	6,170,000	1,560,000
Beginning balance		$ 29,940	$ 29,940	$ 8,004	$ 29,151	$ 8,004
Issuance of private perpetual preferred in exchange for common units (in units)					54,000
Issuance of private perpetual preferred in exchange for common units					$ 789
Distributions			(1,050)	(234)	(3,147)	(702)
Net income (loss)			$ 1,050	$ 234	$ 3,147	$ 702
Ending balance (in units)	6,224,000		6,224,000	1,560,000	6,224,000	1,560,000
Ending balance	$ 29,940		$ 29,940	$ 8,004	$ 29,940	$ 8,004

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities
Net income (loss)	$ (23,599)	$ 55,570
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	143,609	135,179
Impairment charges	6,204	0
Amortization of non-cash items within interest expense	6,803	5,400
Amortization of acquired above- and below-market leases, net	(2,953)	(5,780)
Amortization of acquired below-market ground leases	5,873	5,873
Straight-lining of rental revenue	(5,878)	(13,781)
Equity based compensation	20,174	15,392
Settlement of derivative contract	(20,281)	0
Loss on early extinguishment of debt	86	0
Increase (decrease) in cash flows due to changes in operating assets and liabilities:
Security deposits	20,697	(25,961)
Tenant and other receivables	(431)	149
Deferred leasing costs	(8,241)	(14,513)
Prepaid expenses and other assets	14,680	19,883
Accounts payable and accrued expenses	(1,699)	(2,970)
Deferred revenue and other liabilities	8,509	23,932
Net cash provided by operating activities	163,553	198,373
Cash Flows From Investing Activities
Short-term investments	0	400,000
Development costs	(1,336)	(2)
Additions to building and improvements	(112,018)	(189,666)
Net cash (used in) provided by investing activities	(113,354)	210,332
Cash Flows From Financing Activities
Repayment of mortgage notes payable	(2,939)	(2,829)
Proceeds from unsecured senior notes	175,000	0
Repayment of unsecured senior notes	0	(250,000)
Proceeds from unsecured term loan	175,000	0
Repayment of unsecured term loan	(50,000)	0
Proceeds from unsecured revolving credit facility	550,000	0
Repayment of unsecured revolving credit facility	(550,000)	0
Deferred financing costs	(3,585)	0
Repurchases of common units	(121,950)	0
Distributions	(65,369)	(96,370)
Net cash provided by (used in) financing activities	106,157	(349,199)
Net increase in cash and cash equivalents and restricted cash	156,356	59,506
Cash and cash equivalents and restricted cash—beginning of period	271,597	270,813
Cash and cash equivalents and restricted cash—end of period	427,953	330,319
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	233,946	204,981
Restricted cash at beginning of period	37,651	65,832
Cash and cash equivalents at end of period	373,088	293,710
Restricted cash at end of period	54,865	36,609
Cash and cash equivalents and restricted cash	427,953	330,319
Supplemental disclosures of cash flow information:
Cash paid for interest	57,170	59,173
Cash paid for income taxes	1,197	1,589
Non-cash investing and financing activities:
Building and improvements included in accounts payable and accrued expenses	63,984	77,142
Write-off of fully depreciated assets	54,992	26,516
Derivative instruments at fair values included in accounts payable and accrued expenses	10,222	28,850
Conversion of limited partners' operating partnership units to ESRT partner's capital	23,903	21,654
Issuance of Series 2019 private perpetual preferred in exchange for common units	789	0
Right of use assets	0	29,452
Ground lease liabilities	$ 0	$ 29,452

Description of Business and Org

Description of Business and Organization	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Organization	Description of Business and Organization As used in these condensed 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. (the "Operating Partnership") is the entity through which Empire State Realty Trust, Inc. (“ESRT”), a self-administered and self-managed real estate investment trust ("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. As of September 30, 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 interests) encompassing approximately 9.4 million rentable square feet of office space. Nine of these properties are located in the midtown Manhattan market and 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 approximately 0.5 million rentable square feet of retail space on their ground floor and/or contiguous 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. As of September 30, 2020 , our portfolio included four standalone retail properties located in Manhattan and two standalone retail properties located in the city center of Westport, Connecticut, encompassing approximately 0.2 million rentable square feet in the aggregate. We were organized as a Delaware limited partnership on November 28, 2011 and operations commenced upon completion of the initial public offering of ESRT’s Class A common stock and related formation transactions on October 7, 2013. ESRT, as the sole general partner in our company, has responsibility and discretion in the management and control of 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 September 30, 2020 , ESRT owned approximately 60.0% of our operating partnership units.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies There have been no material changes to the summary of significant accounting policies included in the section entitled "Summary of Significant Accounting Policies" in our December 31, 2019 Annual Report on Form 10-K. Basis of Quarterly Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), for interim financial information, and with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments and eliminations (including intercompany balances and transactions), consisting of normal recurring adjustments, considered necessary for the fair presentation of the financial statements have been included. The results of operations for the periods presented are not necessarily indicative of the results that may be expected for the corresponding full years. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the financial statements for the year ended December 31, 2019 contained in our Annual Report on Form 10-K. We do not consider our business to be subject to material seasonal fluctuations, except that our observatory business is subject to tourism seasonality and currently impacted by the COVID-19 pandemic. Historically, approximately 16.0% to 18.0% of our annual observatory revenue was realized in the first quarter, 26.0% to 28.0% was realized in the second quarter, 31.0% to 33.0% was realized in the third quarter and 23.0% to 25.0% was realized in the fourth quarter. We consolidate entities in which we have a controlling financial interest. In determining whether we have a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, we consider factors such as ownership interest, board representation, management representation, authority to make decisions, and contractual and substantive participating rights of the partners/members. For variable interest entities ("VIE"), we consolidate the entity if we are deemed to have a variable interest in the entity and through that interest we are deemed the primary beneficiary. The primary beneficiary of a VIE is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. The primary beneficiary is required to consolidate the VIE. We had no VIEs as of September 30, 2020 and December 31, 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 condensed consolidated balance sheets and in the condensed consolidated statements of operations by requiring earnings and other comprehensive income to be attributed to controlling and non-controlling interests. Accounting Estimates The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to use estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Significant items subject to such estimates and assumptions include allocation of the purchase price of acquired real estate properties among tangible and intangible assets, determination of the useful life of real estate properties and other long-lived assets, valuation and impairment analysis of commercial real estate properties, right of use assets and other long-lived and indefinite 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 term loan and revolving credit facilities, and equity based compensation. These estimates are prepared using management’s best judgment, after considering past, current, and expected events and economic conditions. Actual results could differ from those estimates. Revenue Recognition 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. 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 Lease

Deferred Costs, Acquired Lease Intangibles and Goodwill	9 Months Ended
	Sep. 30, 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 as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Leasing costs $ 200,684 $ 199,033 Acquired in-place lease value and deferred leasing costs 186,766 200,296 Acquired above-market leases 44,449 49,213 431,899 448,542 Less: accumulated amortization (226,802 ) (224,598 ) Total deferred costs, net, excluding net deferred financing costs $ 205,097 $ 223,944 At September 30, 2020 and December 31, 2019, $2.7 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 condensed consolidated balance sheet. Amortization expense related to deferred leasing costs and acquired deferred leasing costs was $5.4 million and $6.2 million for the three months ended September 30, 2020 and 2019, respectively, and $17.7 million and $18.3 million for the nine months ended September 30, 2020 and 2019, respectively. Amortization expense related to acquired lease intangibles was $1.5 million and $2.4 million for the three months ended September 30, 2020 and 2019, respectively, and $5.9 million and $8.2 million for the nine months ended September 30, 2020 and 2019, respectively. Amortizing acquired intangible assets and liabilities consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (50,223 ) (44,350 ) Acquired below-market ground leases, net $ 346,693 $ 352,566 September 30, 2020 December 31, 2019 Acquired below-market leases $ (82,891 ) $ (100,472 ) Less: accumulated amortization 49,486 60,793 Acquired below-market leases, net $ (33,405 ) $ (39,679 ) Rental revenue related to the amortization of below-market leases, net of above-market leases, was $0.7 million and $1.7 million for the three months ended September 30, 2020 and 2019, respectively, and $3.0 million and $5.8 million for the nine months ended September 30, 2020 and 2019, respectively. As of September 30, 2020 , we had goodwill of $491.5 million . Goodwill was allocated $227.5 million to the observatory reportable segment and $264.0 million to the real estate segment. 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. 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.

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): Principal Balance As of September 30, 2020 September 30, 2020 December 31, 2019 Stated Effective (1) Maturity (2) Mortgage debt collateralized by: Fixed rate mortgage debt Metro Center $ 87,957 $ 89,650 3.59 % 3.67 % 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 % 4.77 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,673 38,251 4.01 % 4.21 % 1/5/2028 10 Bank Street 32,252 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 607,882 610,821 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% 2.03 % 8/29/2021 Unsecured term loan facility (4) 215,000 265,000 LIBOR plus 1.20% 3.77 % 3/19/2025 Unsecured term loan facility (4) 175,000 — LIBOR plus 1.50% 2.99 % 12/31/2026 Total principal 1,972,882 1,675,821 Deferred financing costs, net (9,289 ) (7,247 ) Total $ 1,963,593 $ 1,668,574 ______________ (1) The effective rate is the yield as of September 30, 2020 and includes the stated interest rate, deferred financing cost amortization and interest associated with variable to fixed interest rate swap agreements. (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 at 4.09% and a $16 million loan bearing interest at 6.25% . (4) At September 30, 2020 , we were in compliance with all debt covenants. Principal Payments Aggregate required principal payments at September 30, 2020 are as follows (amounts in thousands): Year Amortization Maturities Total 2020 $ 998 $ — $ 998 2021 4,090 — 4,090 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 Thereafter 25,909 1,842,748 1,868,657 Total $ 52,459 $ 1,920,423 $ 1,972,882 Deferred Financing Costs Deferred financing costs, net, consisted of the following at September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Financing costs $ 28,814 $ 25,315 Less: accumulated amortization (16,848 ) (13,863 ) Total deferred financing costs, net $ 11,966 $ 11,452 At September 30, 2020 and December 31, 2019, $2.7 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 condensed consolidated balance sheet. Amortization expense related to deferred financing costs was $1.0 million and $0.9 million for the three months ended September 30, 2020 and 2019, respectively, and $3.0 million and $2.9 million for the nine months ended September 30, 2020 and 2019, respectively. 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 September 30, 2020 , we had no borrowings under the revolving credit facility and $215.0 million 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. T he 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 September 30, 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 September 30, 2020 , we were in compliance with the covenants under the Credit Facility and the Term Loan Facility. 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 G and H Notes agreement 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 transactions and loss of real estate investment trust qualification. As of September 30, 2020 , we were in compliance with the covenants under the outstanding senior unsecured notes.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts Payable and Accrued Expenses Accounts payable and accrued expenses consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Accrued capital expenditures $ 63,984 $ 90,910 Accounts payable and accrued expenses 34,114 35,084 Interest rate swap agreements liability 10,222 13,330 Accrued interest payable 2,792 3,699 Due to affiliated companies 806 763 Total accounts payable and accrued expenses $ 111,918 $ 143,786

Financial Instruments and Fair

Financial Instruments and Fair Values	9 Months Ended
	Sep. 30, 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 September 30, 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 $10.3 million . If we had breached any of these provisions at September 30, 2020 , we could have been required to settle our obligations under the agreements at their termination value of $10.3 million . As of September 30, 2020 and December 31, 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 September 30, 2020 and December 31, 2019, the fair value of our derivative instruments amounted to $(10.2) million and $(13.3) million , respectively, which is included in accounts payable and accrued expenses on the condensed consolidated balance sheets. 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 September 30, 2020 and 2019, our cash flow hedges are deemed highly effective and a net unrealized gain (loss) of $2.9 million and $(5.9) million for the three months ended September 30, 2020 and 2019, respectively, and a net unrealized gain (loss) of $(13.4) million and $(25.4) million for the nine months ended September 30, 2020 and 2019, respectively, relating to both active and terminated hedges of interest rate risk, are reflected in the condensed consolidated statements of comprehensive income. 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 income (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 September 30, 2020 and December 31, 2019 (dollar amounts in thousands): September 30, 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 $ — $ (10,222 ) $ — $ (4,247 ) Interest rate swap 125,000 3 Month LIBOR 2.9580% July 1, 2019 N/A — — — (9,083 ) $ — $ (10,222 ) $ — $ (13,330 ) During the nine months ended September 30, 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 three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended Nine Months Ended Effects of Cash Flow Hedges September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Amount of gain (loss) recognized in other comprehensive income (loss) $ 64 $ (6,256 ) $ (19,340 ) $ (25,992 ) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (2,873 ) (319 ) (5,986 ) (637 ) The table below shows the effect of our derivative financial instruments designated as cash flow hedges on the condensed consolidated statements of operations for the three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended Nine Months Ended Effects of Cash Flow Hedges September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Total interest (expense) presented in the condensed consolidated statements of operations in which the effects of cash flow hedges are recorded $ (23,360 ) $ (19,426 ) $ (66,906 ) $ (60,712 ) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (2,873 ) (319 ) (5,986 ) (637 ) Fair Valuation The estimated fair values at September 30, 2020 and December 31, 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 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, unsecured term loan facilities, unsecured revolving credit facility and ground lease liabilities 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. The following tables summarize the carrying and estimated fair values of our financial instruments as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses $ 10,222 $ 10,222 $ — $ 10,222 $ — Mortgage notes payable 603,178 636,032 — — 636,032 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,106 1,055,971 — — 1,055,971 Unsecured term loan facilities 387,309 390,000 — — 390,000 December 31, 2019 Estimated Fair Value Carrying 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 Disclosure about the fair value of financial instruments is based on pertinent information available to us as of September 30, 2020

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one to 21 years. Certain leases have renewal options for additional terms. The leases provide for base monthly rentals and reimbursements for real estate taxes, escalations linked to the consumer price index or common area maintenance known as operating expense escalation. Operating expense reimbursements are reflected in our September 30, 2020 and 2019 condensed consolidated statements of operations as rental revenue. 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 three and nine months ended September 30, 2020 and 2019 are as follows (amounts in thousands): Three Months Ended Nine Months Ended Rental revenue September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Fixed payments $ 122,976 $ 129,030 $ 375,882 $ 380,647 Variable payments 16,933 21,195 50,139 54,066 Total rental revenue $ 139,909 $ 150,225 $ 426,021 $ 434,713 As of September 30, 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): Remainder of 2020 $ 126,997 2021 502,160 2022 484,131 2023 459,992 2024 423,039 Thereafter 2,139,096 $ 4,135,415 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 $29.2 million and lease liabilities of $29.2 million in our consolidated balance sheet as of September 30, 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 September 30, 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 September 30, 2020 was 49.6 years. As of September 30, 2020 , the following table summarizes our future minimum lease payments discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): Remainder of 2020 $ 380 2021 1,518 2022 1,518 2023 1,518 2024 1,518 Thereafter 66,780 Total undiscounted cash flows 73,232 Present value discount (44,078 ) Ground lease liabilities $ 29,154
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one to 21 years. Certain leases have renewal options for additional terms. The leases provide for base monthly rentals and reimbursements for real estate taxes, escalations linked to the consumer price index or common area maintenance known as operating expense escalation. Operating expense reimbursements are reflected in our September 30, 2020 and 2019 condensed consolidated statements of operations as rental revenue. 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 three and nine months ended September 30, 2020 and 2019 are as follows (amounts in thousands): Three Months Ended Nine Months Ended Rental revenue September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Fixed payments $ 122,976 $ 129,030 $ 375,882 $ 380,647 Variable payments 16,933 21,195 50,139 54,066 Total rental revenue $ 139,909 $ 150,225 $ 426,021 $ 434,713 As of September 30, 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): Remainder of 2020 $ 126,997 2021 502,160 2022 484,131 2023 459,992 2024 423,039 Thereafter 2,139,096 $ 4,135,415 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 $29.2 million and lease liabilities of $29.2 million in our consolidated balance sheet as of September 30, 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 September 30, 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 September 30, 2020 was 49.6 years. As of September 30, 2020 , the following table summarizes our future minimum lease payments discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): Remainder of 2020 $ 380 2021 1,518 2022 1,518 2023 1,518 2024 1,518 Thereafter 66,780 Total undiscounted cash flows 73,232 Present value discount (44,078 ) Ground lease liabilities $ 29,154

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings Except as described below, as of September 30, 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 condensed 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. Respondents believe that such award in favor of the Claimants is entirely without merit, and are in active discussion about their next steps. 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 September 30, 2020 , we estimate that we will incur approximately $130.1 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 September 30, 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. 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 September 30, 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 September 30, 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 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

Capital

Capital	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Capital	Capital As of September 30, 2020 , there were 288,375,949 operating partnership units outstanding, of which 172,992,089 , or 60.0% , were owned by ESRT and 115,383,860 , or 40.0% , 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 ESRT and the 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 ESRT common stock is 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 Series PR 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 operating partnership 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 ESRT's Board of Directors reauthorized the repurchase of up to $500 million of ESRT Class A common stock and the Operating Partnership’s Series ES, Series 250 and Series 60 operating partnership units through December 31, 2020. Under the program, ESRT may purchase ESRT Class A common stock and we may purchase our 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 ESRT and us at our discretion and will be subject to stock price, availability, trading volume and general market conditions. The authorization does not obligate ESRT or us to acquire any particular amount of securities, and the program may be suspended or discontinued at ESRT and our discretion without prior notice. The following table summarizes ESRT's purchases of equity securities in each of the three months ended September 30, 2020 and the month of October 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) July 2020 656,318 $ 6.72 656,318 $ 380,982 August 2020 — $ — — $ 380,982 September 2020 477,620 $ 6.14 477,620 $ 378,050 October 2020 1,952,013 $ 6.21 1,952,013 $ 365,934 Private Perpetual Preferred Units As of September 30, 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 Total distributions paid to OP unitholders were $0.0 million and $62.2 million for the three and nine months ended September 30, 2020 , respectively, and $31.9 million and $95.7 million for the three and nine months ended September 30, 2019, respectively. Total distributions paid to preferred unitholders were $1.1 million and $3.1 million for the three and nine months ended September 30, 2020 , respectively, and $0.2 million and $0.7 million for the three and nine months ended September 30, 2019, 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 is authorized for issuance under awards granted pursuant to the 2019 Plan, and as of September 30, 2020 , 8.5 million shares of ESRT common stock remain available for future issuance. 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 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 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. Our named executive officers can 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. 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 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 or four years from the date of grant, subject generally to the grantee's continued employment. The first installment vests on the respective grant dates in May 2021 and the remainder will vest thereafter in two or 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 May 7, 2020. 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 May 7, 2023 and the second installment vesting on May 7, 2024, subject generally to the grantee's continued employment on those dates. In August 2020, we granted R. Paige Hood, our new non-employee director, a total of 25,242 LTIP units that are subject to time-based vesting with a fair market value of $0.2 million . These awards vest ratably over three years from the date of the grant, subject generally to his continued service on our Board of Directors. 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 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. Our named executive officers can 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. 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. In October 2019 and May 2019, we made grants of LTIP units to our non-employee directors under the 2019 Plan. In the aggregate, 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 May 17, 2019, subject generally to the director's continued service on our Board of Directors. The first installment vests on May 17, 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 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 and (ii) the date on which the employee has first completed ten years of continuous service with us or our affiliates. During the second quarter of 2020, the Board approved changing the definition of retirement age from 60 to 65 starting with the grant awards issued in March 2020 under the 2019 Plan. 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 three or four years depending on retirement eligibility. For the market-based LTIP units, the fair value of the awards was estimated using a Monte Carlo Simulation model and 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. 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 nine months ended September 30, 2020 were valued at $28.1 million . The weighted average per unit or share fair value was $5.43 for grants issued in 2020. 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% . No other stock options, dividend equivalents, or stock appreciation rights were issued or outstanding in 2020. The following is a summary of ESRT restricted stock and LTIP unit activity for the nine months ended September 30, 2020 : Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2019 118,918 5,986,569 $ 9.73 Vested (57,599 ) (1,052,692 ) 14.04 Granted 161,449 5,011,693 5.43 Forfeited or unearned (1,136 ) (2,201,453 ) 7.57 Unvested balance at September 30, 2020 221,632 7,744,117 $ 6.93 The LTIP unit and ESRT restricted stock awards are treated for accounting purposes as immediately vested upon the later of (i) the date the grantee attains the age of 60 or 65 , as applicable, and (ii) the date on which 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 performance-based awards, and accordingly, we recognized $0.4 million and $2.3 million for the three and nine months ended September 30, 2020 , respectively, and $0.3 million and $1.8 million for the three and nine months ended September 30, 2019, respectively. Unrecognized compensation expense was $1.7 million at September 30, 2020 , which will be recognized over a weighted average period of 2.3 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 noncash compensation expense of $5.1 million and $17.9 million for the three and nine months ended September 30, 2020 , respectively, and $3.4 million and $13.6 million for the three and nine months ended September 30, 2019, respectively. Unrecognized compensation expense was $31.4 million at September 30, 2020 , which will be recognized over a weighted average period of 2.3 years. Earnings Per Unit Earnings per unit for the three and nine months ended September 30, 2020 and 2019 is computed as follows (amounts in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Numerator: Net income (loss) $ (12,269 ) $ 26,784 $ (23,599 ) $ 55,570 Private perpetual preferred unit distributions (1,050 ) (234 ) (3,147 ) (702 ) Earnings allocated to unvested units (342 ) (243 ) (985 ) (646 ) Net income (loss) attributable to common unitholders - basic and diluted $ (13,661 ) $ 26,307 $ (27,731 ) $ 54,222 Denominator: Weighted average units outstanding - basic 280,940 298,151 285,640 298,117 Effect of dilutive securities: Stock-based compensation plans — — — — Weighted average units outstanding - diluted 280,940 298,151 285,640 298,117 Earnings per share: Basic $ (0.05 ) $ 0.09 $ (0.10 ) $ 0.18 Diluted $ (0.05 ) $ 0.09 $ (0.10 ) $ 0.18 There were zero and 169,848 antidilutive shares and LTIP units for the three and nine months ended September 30, 2020 , respectively, and 452,457 and 288,053 antidilutive shares and LTIP units for the three and nine months ended September 30, 2019, respectively.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Supervisory Fee Revenue We earned supervisory fees from entities affiliated with Anthony E. Malkin, our Chairman and Chief Executive Officer, of $0.2 million and $0.2 million for the three months ended September 30, 2020 and 2019, respectively, and $0.7 million and $0.7 million for the nine months ended September 30, 2020 and 2019, respectively. These fees are included within third-party management and other fees. Property Management Fee Revenue We earned property management fees from entities affiliated with Anthony E. Malkin of $0.1 million and $0.1 million for the three months ended September 30, 2020 and 2019, respectively, and $0.2 million and $0.2 million for the nine months ended September 30, 2020 and 2019, respectively. These fees are included within third-party management and other fees. Other We receive rent generally at market rental rate for 5,447 square feet of leased space from entities affiliated with Anthony E. Malkin at one of our properties. Under the lease, the tenant has the right to cancel such lease without special payment on 90 days’ notice. We also have a shared use agreement with such tenant, to occupy a portion of the leased premises as the office location for Peter L. Malkin, our chairman emeritus and employee, utilizing approximately 15% of the space, for which we pay to such tenant an allocable pro rata share of the cost. We also have agreements with these entities and excluded properties and businesses to provide them with general computer-related support services. Total revenue aggregated $0.1 million and $0.1 million for the three months ended September 30, 2020 and 2019, respectively, and $0.2 million and $0.2 million for the nine months ended September 30, 2020 and 2019, respectively.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 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, redevelopment, repositioning and disposition of our traditional real estate assets. Our observatory segment includes the operation of 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 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. The following tables provide components of segment profit for each segment for the three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended September 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 139,909 $ — $ — $ 139,909 Intercompany rental revenue (2,233 ) — 2,233 — Observatory revenue — 4,419 — 4,419 Lease termination fees 331 — — 331 Third-party management and other fees 283 — — 283 Other revenue and fees 1,633 — — 1,633 Total revenues 139,923 4,419 2,233 146,575 Operating expenses: Property operating expenses 33,836 — — 33,836 Intercompany rent expense — (2,233 ) 2,233 — Ground rent expense 2,331 — — 2,331 General and administrative expenses 14,517 — — 14,517 Observatory expenses — 5,931 — 5,931 Real estate taxes 31,196 — — 31,196 Impairment charge 2,103 — — 2,103 Depreciation and amortization 44,679 54 — 44,733 Total operating expenses 128,662 3,752 2,233 134,647 Total operating income (loss) 11,261 667 — 11,928 Other income (expense): Interest income 360 6 — 366 Interest expense (23,360 ) — — (23,360 ) Loss on early extinguishment of debt — — — — IPO litigation expense (1,165 ) — — (1,165 ) Income (loss) before income taxes (12,904 ) 673 — (12,231 ) Income tax (expense) benefit (196 ) 158 — (38 ) Net income (loss) $ (13,100 ) $ 831 $ — $ (12,269 ) Segment assets $ 3,771,476 $ 239,238 $ — $ 4,010,714 Expenditures for segment assets $ 30,831 $ 516 $ — $ 31,347 Three Months Ended September 30, 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 150,225 $ — $ — $ 150,225 Intercompany rental revenue 23,242 — (23,242 ) — Observatory revenue — 37,575 — 37,575 Lease termination fees 2,361 — — 2,361 Third-party management and other fees 304 — — 304 Other revenue and fees 2,408 — — 2,408 Total revenues 178,540 37,575 (23,242 ) 192,873 Operating expenses: Property operating expenses 47,894 — — 47,894 Intercompany rent expense — 23,242 (23,242 ) — Ground rent expense 2,331 — — 2,331 General and administrative expenses 14,421 — — 14,421 Observatory expenses — 9,089 — 9,089 Real estate taxes 29,599 — — 29,599 Depreciation and amortization 44,253 7 — 44,260 Total operating expenses 138,498 32,338 (23,242 ) 147,594 Total operating income 40,042 5,237 — 45,279 Other income (expense): Interest income 2,269 — — 2,269 Interest expense (19,426 ) — — (19,426 ) Income before income taxes 22,885 5,237 — 28,122 Income tax expense (267 ) (1,071 ) — (1,338 ) Net income $ 22,618 $ 4,166 $ — $ 26,784 Segment assets $ 3,659,592 $ 265,725 $ — $ 3,925,317 Expenditures for segment assets $ 42,901 $ 18,375 $ — $ 61,276 Nine Months Ended September 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 426,021 $ — $ — $ 426,021 Intercompany rental revenue 13,356 — (13,356 ) — Observatory revenue — 24,049 — 24,049 Lease termination fees 1,575 — — 1,575 Third-party management and other fees 930 — — 930 Other revenue and fees 5,254 — — 5,254 Total revenues 447,136 24,049 (13,356 ) 457,829 Operating expenses: Property operating expenses 105,054 — — 105,054 Intercompany rent expense — 13,356 (13,356 ) — Ground rent expense 6,994 — — 6,994 General and administrative expenses 48,617 — — 48,617 Observatory expenses — 18,087 — 18,087 Real estate taxes 90,029 — — 90,029 Impairment charges 6,204 — — 6,204 Depreciation and amortization 143,522 87 — 143,609 Total operating expenses 400,420 31,530 (13,356 ) 418,594 Total operating income (loss) 46,716 (7,481 ) — 39,235 Other income (expense): Interest income 2,438 91 — 2,529 Interest expense (66,906 ) — — (66,906 ) Loss on early extinguishment of debt (86 ) — — (86 ) IPO litigation expense (1,165 ) — — (1,165 ) Loss before income taxes (19,003 ) (7,390 ) — (26,393 ) Income tax (expense) benefit (692 ) 3,486 — 2,794 Net loss $ (19,695 ) $ (3,904 ) $ — $ (23,599 ) Expenditures for segment assets $ 77,503 $ 2,748 $ — $ 80,251 Nine Months Ended September 30, 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 434,713 $ — $ — $ 434,713 Intercompany rental revenue 58,754 — (58,754 ) — Observatory revenue — 91,039 — 91,039 Lease termination fees 3,112 — — 3,112 Third-party management and other fees 955 — — 955 Other revenue and fees 6,591 — — 6,591 Total revenues 504,125 91,039 (58,754 ) 536,410 Operating expenses: Property operating expenses 131,076 — — 131,076 Intercompany rent expense — 58,754 (58,754 ) — Ground rent expense 6,994 — — 6,994 General and administrative expenses 44,445 — — 44,445 Observatory expenses — 25,024 — 25,024 Real estate taxes 86,098 — — 86,098 Depreciation and amortization 135,157 22 — 135,179 Total operating expenses 403,770 83,800 (58,754 ) 428,816 Total operating income 100,355 7,239 — 107,594 Other income (expense): Interest income 9,907 — — 9,907 Interest expense (60,712 ) — — (60,712 ) Income before income taxes 49,550 7,239 — 56,789 Income tax expense (762 ) (457 ) — (1,219 ) Net income $ 48,788 $ 6,782 $ — $ 55,570 Expenditures for segment assets $ 134,865 $ 46,703 $ — $ 181,568 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 2020, we also wrote off $2.1 million of prior expenditures on a build-to-suit development project in our real estate segment that was halted due to reconsideration by the user driven by the COVID-19 pandemic. For the nine months ended September 30, 2020, the total $6.2 million write-off is shown as Impairment charge in the condensed consolidated statements of operations.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events None.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Quarterly Presentation	The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), for interim financial information, and with the rules and regulations of the Securities and Exchange Commission (the "SEC"). Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments and eliminations (including intercompany balances and transactions), consisting of normal recurring adjustments, considered necessary for the fair presentation of the financial statements have been included.
Principles of Consolidation	The results of operations for the periods presented are not necessarily indicative of the results that may be expected for the corresponding full years. These financial statements should be read in conjunction with the financial statements and accompanying notes included in the financial statements for the year ended December 31, 2019 contained in our Annual Report on Form 10-K. We do not consider our business to be subject to material seasonal fluctuations, except that our observatory business is subject to tourism seasonality and currently impacted by the COVID-19
Principles of Consolidation for Variable Interest Entities	We consolidate entities in which we have a controlling financial interest. In determining whether we have a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, we consider factors such as ownership interest, board representation, management representation, authority to make decisions, and contractual and substantive participating rights of the partners/members. For variable interest entities ("VIE"), we consolidate the entity if we are deemed to have a variable interest in the entity and through that interest we are deemed the primary beneficiary. The primary beneficiary of a VIE is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. The primary beneficiary is required to consolidate the VIE. We had no VIEs as of September 30, 2020 and December 31, 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 condensed consolidated balance sheets and in the condensed consolidated statements of operations by requiring earnings and other comprehensive income to be attributed to controlling and non-controlling interests.
Accounting Estimates	The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to use estimates and assumptions that in certain circumstances affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. Significant items subject to such estimates and assumptions include allocation of the purchase price of acquired real estate properties among tangible and intangible assets, determination of the useful life of real estate properties and other long-lived assets, valuation and impairment analysis of commercial real estate properties, right of use assets and other long-lived and indefinite 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 term loan and revolving credit facilities, and equity based compensation. These estimates are prepared using management’s best judgment, after considering past, current, and expected events and economic conditions. Actual results could differ from those estimates.
Revenue Recognition	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.
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)	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs, Net	Deferred costs, net, consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Leasing costs $ 200,684 $ 199,033 Acquired in-place lease value and deferred leasing costs 186,766 200,296 Acquired above-market leases 44,449 49,213 431,899 448,542 Less: accumulated amortization (226,802 ) (224,598 ) Total deferred costs, net, excluding net deferred financing costs $ 205,097 $ 223,944 Deferred financing costs, net, consisted of the following at September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Financing costs $ 28,814 $ 25,315 Less: accumulated amortization (16,848 ) (13,863 ) Total deferred financing costs, net $ 11,966 $ 11,452
Amortizing Acquired Intangible Assets and Liabilities	Amortizing acquired intangible assets and liabilities consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (50,223 ) (44,350 ) Acquired below-market ground leases, net $ 346,693 $ 352,566 September 30, 2020 December 31, 2019 Acquired below-market leases $ (82,891 ) $ (100,472 ) Less: accumulated amortization 49,486 60,793 Acquired below-market leases, net $ (33,405 ) $ (39,679 )

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Debt consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): Principal Balance As of September 30, 2020 September 30, 2020 December 31, 2019 Stated Effective (1) Maturity (2) Mortgage debt collateralized by: Fixed rate mortgage debt Metro Center $ 87,957 $ 89,650 3.59 % 3.67 % 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 % 4.77 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,673 38,251 4.01 % 4.21 % 1/5/2028 10 Bank Street 32,252 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 607,882 610,821 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% 2.03 % 8/29/2021 Unsecured term loan facility (4) 215,000 265,000 LIBOR plus 1.20% 3.77 % 3/19/2025 Unsecured term loan facility (4) 175,000 — LIBOR plus 1.50% 2.99 % 12/31/2026 Total principal 1,972,882 1,675,821 Deferred financing costs, net (9,289 ) (7,247 ) Total $ 1,963,593 $ 1,668,574 ______________ (1) The effective rate is the yield as of September 30, 2020 and includes the stated interest rate, deferred financing cost amortization and interest associated with variable to fixed interest rate swap agreements. (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 at 4.09% and a $16 million loan bearing interest at 6.25% . (4) At September 30, 2020 , we were in compliance with all debt covenants.
Aggregate Required Principal Payments	Aggregate required principal payments at September 30, 2020 are as follows (amounts in thousands): Year Amortization Maturities Total 2020 $ 998 $ — $ 998 2021 4,090 — 4,090 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 Thereafter 25,909 1,842,748 1,868,657 Total $ 52,459 $ 1,920,423 $ 1,972,882
Deferred Costs, Net	Deferred costs, net, consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Leasing costs $ 200,684 $ 199,033 Acquired in-place lease value and deferred leasing costs 186,766 200,296 Acquired above-market leases 44,449 49,213 431,899 448,542 Less: accumulated amortization (226,802 ) (224,598 ) Total deferred costs, net, excluding net deferred financing costs $ 205,097 $ 223,944 Deferred financing costs, net, consisted of the following at September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Financing costs $ 28,814 $ 25,315 Less: accumulated amortization (16,848 ) (13,863 ) Total deferred financing costs, net $ 11,966 $ 11,452

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 December 31, 2019 Accrued capital expenditures $ 63,984 $ 90,910 Accounts payable and accrued expenses 34,114 35,084 Interest rate swap agreements liability 10,222 13,330 Accrued interest payable 2,792 3,699 Due to affiliated companies 806 763 Total accounts payable and accrued expenses $ 111,918 $ 143,786

Financial Instruments and Fai_2

Financial Instruments and Fair Values (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Summary of the Terms of Agreements and the Fair Value of Derivative Financial Instruments	The table below summarizes the terms of agreements and the fair values of our derivative financial instruments as of September 30, 2020 and December 31, 2019 (dollar amounts in thousands): September 30, 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 $ — $ (10,222 ) $ — $ (4,247 ) Interest rate swap 125,000 3 Month LIBOR 2.9580% July 1, 2019 N/A — — — (9,083 ) $ — $ (10,222 ) $ — $ (13,330 )
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 three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended Nine Months Ended Effects of Cash Flow Hedges September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Amount of gain (loss) recognized in other comprehensive income (loss) $ 64 $ (6,256 ) $ (19,340 ) $ (25,992 ) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (2,873 ) (319 ) (5,986 ) (637 ) The table below shows the effect of our derivative financial instruments designated as cash flow hedges on the condensed consolidated statements of operations for the three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended Nine Months Ended Effects of Cash Flow Hedges September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Total interest (expense) presented in the condensed consolidated statements of operations in which the effects of cash flow hedges are recorded $ (23,360 ) $ (19,426 ) $ (66,906 ) $ (60,712 ) Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense (2,873 ) (319 ) (5,986 ) (637 )
Summary of the Carrying and Estimated Fair Values of Financial Instruments	The following tables summarize the carrying and estimated fair values of our financial instruments as of September 30, 2020 and December 31, 2019 (amounts in thousands): September 30, 2020 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swaps included in accounts payable and accrued expenses $ 10,222 $ 10,222 $ — $ 10,222 $ — Mortgage notes payable 603,178 636,032 — — 636,032 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,106 1,055,971 — — 1,055,971 Unsecured term loan facilities 387,309 390,000 — — 390,000 December 31, 2019 Estimated Fair Value Carrying 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 (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Schedule of Components of Rental Revenue	The components of rental revenue for the three and nine months ended September 30, 2020 and 2019 are as follows (amounts in thousands): Three Months Ended Nine Months Ended Rental revenue September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Fixed payments $ 122,976 $ 129,030 $ 375,882 $ 380,647 Variable payments 16,933 21,195 50,139 54,066 Total rental revenue $ 139,909 $ 150,225 $ 426,021 $ 434,713
Schedule of Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received	As of September 30, 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): Remainder of 2020 $ 126,997 2021 502,160 2022 484,131 2023 459,992 2024 423,039 Thereafter 2,139,096 $ 4,135,415
Schedule of Future Minimum Lease Payments	As of September 30, 2020 , the following table summarizes our future minimum lease payments discounted by our incremental borrowing rates to calculate the lease liabilities of our leases (amounts in thousands): Remainder of 2020 $ 380 2021 1,518 2022 1,518 2023 1,518 2024 1,518 Thereafter 66,780 Total undiscounted cash flows 73,232 Present value discount (44,078 ) Ground lease liabilities $ 29,154

Capital (Tables)

Capital (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Schedule of Equity Securities Repurchased	The following table summarizes ESRT's purchases of equity securities in each of the three months ended September 30, 2020 and the month of October 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) July 2020 656,318 $ 6.72 656,318 $ 380,982 August 2020 — $ — — $ 380,982 September 2020 477,620 $ 6.14 477,620 $ 378,050 October 2020 1,952,013 $ 6.21 1,952,013 $ 365,934
Summary of ERST Restricted Stock and LTIP Unit	The following is a summary of ESRT restricted stock and LTIP unit activity for the nine months ended September 30, 2020 : Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2019 118,918 5,986,569 $ 9.73 Vested (57,599 ) (1,052,692 ) 14.04 Granted 161,449 5,011,693 5.43 Forfeited or unearned (1,136 ) (2,201,453 ) 7.57 Unvested balance at September 30, 2020 221,632 7,744,117 $ 6.93
Earnings Per Unit	Earnings per unit for the three and nine months ended September 30, 2020 and 2019 is computed as follows (amounts in thousands, except per share amounts): Three Months Ended Nine Months Ended September 30, 2020 September 30, 2019 September 30, 2020 September 30, 2019 Numerator: Net income (loss) $ (12,269 ) $ 26,784 $ (23,599 ) $ 55,570 Private perpetual preferred unit distributions (1,050 ) (234 ) (3,147 ) (702 ) Earnings allocated to unvested units (342 ) (243 ) (985 ) (646 ) Net income (loss) attributable to common unitholders - basic and diluted $ (13,661 ) $ 26,307 $ (27,731 ) $ 54,222 Denominator: Weighted average units outstanding - basic 280,940 298,151 285,640 298,117 Effect of dilutive securities: Stock-based compensation plans — — — — Weighted average units outstanding - diluted 280,940 298,151 285,640 298,117 Earnings per share: Basic $ (0.05 ) $ 0.09 $ (0.10 ) $ 0.18 Diluted $ (0.05 ) $ 0.09 $ (0.10 ) $ 0.18

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Components of Segment Profit for Each Segment	The following tables provide components of segment profit for each segment for the three and nine months ended September 30, 2020 and 2019 (amounts in thousands): Three Months Ended September 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 139,909 $ — $ — $ 139,909 Intercompany rental revenue (2,233 ) — 2,233 — Observatory revenue — 4,419 — 4,419 Lease termination fees 331 — — 331 Third-party management and other fees 283 — — 283 Other revenue and fees 1,633 — — 1,633 Total revenues 139,923 4,419 2,233 146,575 Operating expenses: Property operating expenses 33,836 — — 33,836 Intercompany rent expense — (2,233 ) 2,233 — Ground rent expense 2,331 — — 2,331 General and administrative expenses 14,517 — — 14,517 Observatory expenses — 5,931 — 5,931 Real estate taxes 31,196 — — 31,196 Impairment charge 2,103 — — 2,103 Depreciation and amortization 44,679 54 — 44,733 Total operating expenses 128,662 3,752 2,233 134,647 Total operating income (loss) 11,261 667 — 11,928 Other income (expense): Interest income 360 6 — 366 Interest expense (23,360 ) — — (23,360 ) Loss on early extinguishment of debt — — — — IPO litigation expense (1,165 ) — — (1,165 ) Income (loss) before income taxes (12,904 ) 673 — (12,231 ) Income tax (expense) benefit (196 ) 158 — (38 ) Net income (loss) $ (13,100 ) $ 831 $ — $ (12,269 ) Segment assets $ 3,771,476 $ 239,238 $ — $ 4,010,714 Expenditures for segment assets $ 30,831 $ 516 $ — $ 31,347 Three Months Ended September 30, 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 150,225 $ — $ — $ 150,225 Intercompany rental revenue 23,242 — (23,242 ) — Observatory revenue — 37,575 — 37,575 Lease termination fees 2,361 — — 2,361 Third-party management and other fees 304 — — 304 Other revenue and fees 2,408 — — 2,408 Total revenues 178,540 37,575 (23,242 ) 192,873 Operating expenses: Property operating expenses 47,894 — — 47,894 Intercompany rent expense — 23,242 (23,242 ) — Ground rent expense 2,331 — — 2,331 General and administrative expenses 14,421 — — 14,421 Observatory expenses — 9,089 — 9,089 Real estate taxes 29,599 — — 29,599 Depreciation and amortization 44,253 7 — 44,260 Total operating expenses 138,498 32,338 (23,242 ) 147,594 Total operating income 40,042 5,237 — 45,279 Other income (expense): Interest income 2,269 — — 2,269 Interest expense (19,426 ) — — (19,426 ) Income before income taxes 22,885 5,237 — 28,122 Income tax expense (267 ) (1,071 ) — (1,338 ) Net income $ 22,618 $ 4,166 $ — $ 26,784 Segment assets $ 3,659,592 $ 265,725 $ — $ 3,925,317 Expenditures for segment assets $ 42,901 $ 18,375 $ — $ 61,276 Nine Months Ended September 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 426,021 $ — $ — $ 426,021 Intercompany rental revenue 13,356 — (13,356 ) — Observatory revenue — 24,049 — 24,049 Lease termination fees 1,575 — — 1,575 Third-party management and other fees 930 — — 930 Other revenue and fees 5,254 — — 5,254 Total revenues 447,136 24,049 (13,356 ) 457,829 Operating expenses: Property operating expenses 105,054 — — 105,054 Intercompany rent expense — 13,356 (13,356 ) — Ground rent expense 6,994 — — 6,994 General and administrative expenses 48,617 — — 48,617 Observatory expenses — 18,087 — 18,087 Real estate taxes 90,029 — — 90,029 Impairment charges 6,204 — — 6,204 Depreciation and amortization 143,522 87 — 143,609 Total operating expenses 400,420 31,530 (13,356 ) 418,594 Total operating income (loss) 46,716 (7,481 ) — 39,235 Other income (expense): Interest income 2,438 91 — 2,529 Interest expense (66,906 ) — — (66,906 ) Loss on early extinguishment of debt (86 ) — — (86 ) IPO litigation expense (1,165 ) — — (1,165 ) Loss before income taxes (19,003 ) (7,390 ) — (26,393 ) Income tax (expense) benefit (692 ) 3,486 — 2,794 Net loss $ (19,695 ) $ (3,904 ) $ — $ (23,599 ) Expenditures for segment assets $ 77,503 $ 2,748 $ — $ 80,251 Nine Months Ended September 30, 2019 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 434,713 $ — $ — $ 434,713 Intercompany rental revenue 58,754 — (58,754 ) — Observatory revenue — 91,039 — 91,039 Lease termination fees 3,112 — — 3,112 Third-party management and other fees 955 — — 955 Other revenue and fees 6,591 — — 6,591 Total revenues 504,125 91,039 (58,754 ) 536,410 Operating expenses: Property operating expenses 131,076 — — 131,076 Intercompany rent expense — 58,754 (58,754 ) — Ground rent expense 6,994 — — 6,994 General and administrative expenses 44,445 — — 44,445 Observatory expenses — 25,024 — 25,024 Real estate taxes 86,098 — — 86,098 Depreciation and amortization 135,157 22 — 135,179 Total operating expenses 403,770 83,800 (58,754 ) 428,816 Total operating income 100,355 7,239 — 107,594 Other income (expense): Interest income 9,907 — — 9,907 Interest expense (60,712 ) — — (60,712 ) Income before income taxes 49,550 7,239 — 56,789 Income tax expense (762 ) (457 ) — (1,219 ) Net income $ 48,788 $ 6,782 $ — $ 55,570 Expenditures for segment assets $ 134,865 $ 46,703 $ — $ 181,568 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 2020, we also wrote off $2.1 million of prior expenditures on a build-to-suit development project in our real estate segment that was halted due to reconsideration by the user driven by the COVID-19 pandemic. For the nine months ended September 30, 2020, the total $6.2 million write-off is shown as Impairment charge in the condensed consolidated statements of operations.

Description of Business and O_2

Description of Business and Organization (Details) ft² in Millions	9 Months Ended
	Sep. 30, 2020ft²parceloffice_and_property
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in square feet)	10.1
Office Building
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in square feet)	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 square feet)	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 square feet)	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 Site | Manhattan and Westport, Connecticut
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in square feet)	0.2
Retail Site | Manhattan
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in square feet)	0.5
Number of properties | office_and_property	4
Retail Site | 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 square feet)	0.4
Empire State Realty OP | Empire State Realty Trust
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
OP units owned by the Company (as a percent)	60.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	Sep. 30, 2020
Minimum
Accounting Policies [Line Items]
Observatory revenue realized during the first quarter, previous ten years (as a percent)	16.00%
Observatory revenue realized during the second quarter, previous ten years (as a percent)	26.00%
Observatory revenue realized during the third quarter, previous ten years (as a percent)	31.00%
Observatory revenue realized during the fourth quarter, previous ten years (as a percent)	23.00%
Maximum
Accounting Policies [Line Items]
Observatory revenue realized during the first quarter, previous ten years (as a percent)	18.00%
Observatory revenue realized during the second quarter, previous ten years (as a percent)	28.00%
Observatory revenue realized during the third quarter, previous ten years (as a percent)	33.00%
Observatory revenue realized during the fourth quarter, previous ten years (as a percent)	25.00%

Deferred Costs, Acquired Leas_3

Deferred Costs, Acquired Lease Intangibles and Goodwill - Deferred Costs, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Leasing costs	$ 200,684	$ 199,033
Deferred costs, gross	431,899	448,542
Less: accumulated amortization	(226,802)	(224,598)
Total deferred costs, net, excluding net deferred financing costs	205,097	223,944
Acquired in-place lease value and deferred leasing costs
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	186,766	200,296
Acquired above-market leases
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	$ 44,449	$ 49,213

Deferred Costs, Acquired Leas_4

Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Deferred Costs [Line Items]
Amortization expense related to deferred leasing costs	$ 5,400	$ 6,200	$ 17,700	$ 18,300
Rental revenue related to amortization of below-market leases, net of above-market leases	700	1,700	2,953	5,780
Goodwill	491,479		491,479			$ 491,479
Lease agreements
Deferred Costs [Line Items]
Amortization expense related to acquired lease intangibles	1,500	$ 2,400	5,900	$ 8,200
Observatory
Deferred Costs [Line Items]
Goodwill	227,500		227,500
Real estate
Deferred Costs [Line Items]
Goodwill	264,000		264,000
Revolving credit facility | Unsecured revolving credit facility
Deferred Costs [Line Items]
Net deferred financing costs	$ 2,700		$ 2,700			$ 4,200
Observatory
Deferred Costs [Line Items]
Fair value in excess of carrying value (less than) (as a percent)					5.00%

Deferred Costs, Acquired Leas_5

Deferred Costs, Acquired Lease Intangibles and Goodwill - Amortizing Acquired Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Acquired below-market ground leases
Acquired below-market ground leases, gross	$ 396,916	$ 396,916
Less: accumulated amortization	(50,223)	(44,350)
Acquired below-market ground leases, net	346,693	352,566
Acquired below-market leases
Acquired below-market leases, gross	(82,891)	(100,472)
Less: accumulated amortization	49,486	60,793
Acquired below-market leases, net	$ (33,405)	$ (39,679)

Debt - Long-Term Debt (Details)

Debt - Long-Term Debt (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Mar. 17, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Unsecured revolving credit facility, net	$ 0		$ 0
Total principal	1,972,882,000
Deferred financing costs, net	(11,966,000)		(11,452,000)
Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	607,882,000		610,821,000
Mortgages, senior notes, and unsecured term loan facilities, not including unsecured revolving credit facility
Debt Instrument [Line Items]
Total principal	1,972,882,000		1,675,821,000
Deferred financing costs, net	(9,289,000)		(7,247,000)
Total	1,963,593,000		1,668,574,000
Metro Center | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 87,957,000		89,650,000
Stated rate (as a percent)	3.59%
Effective Rate (as a percentage)	3.67%
10 Union Square | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 50,000,000		50,000,000
Stated rate (as a percent)	3.70%
Effective Rate (as a percentage)	3.97%
1542 Third Avenue | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 30,000,000		30,000,000
Stated rate (as a percent)	4.29%
Effective Rate (as a percentage)	4.53%
First Stamford Place | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 180,000,000		180,000,000
Stated rate (as a percent)	4.28%
Effective Rate (as a percentage)	4.77%
First Stamford Place - First Lien | Mortgages
Debt Instrument [Line Items]
Stated rate (as a percent)	4.09%
Face amount	$ 164,000,000
First Stamford Place - Second Lien | Mortgages
Debt Instrument [Line Items]
Stated rate (as a percent)	6.25%
Face amount	$ 16,000,000
1010 Third Avenue and 77 West 55th Street | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 37,673,000		38,251,000
Stated rate (as a percent)	4.01%
Effective Rate (as a percentage)	4.21%
10 Bank Street | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 32,252,000		32,920,000
Stated rate (as a percent)	4.23%
Effective Rate (as a percentage)	4.36%
383 Main Avenue | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 30,000,000		30,000,000
Stated rate (as a percent)	4.44%
Effective Rate (as a percentage)	4.55%
1333 Broadway | Mortgages
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 160,000,000		160,000,000
Stated rate (as a percent)	4.21%
Effective Rate (as a percentage)	4.29%
Senior unsecured notes, Series A | Senior notes
Debt Instrument [Line Items]
Total	$ 100,000,000		100,000,000
Stated rate (as a percent)	3.93%
Effective Rate (as a percentage)	3.96%
Senior unsecured notes, Series B | Senior notes
Debt Instrument [Line Items]
Total	$ 125,000,000		125,000,000
Stated rate (as a percent)	4.09%
Effective Rate (as a percentage)	4.12%
Senior unsecured notes, Series C | Senior notes
Debt Instrument [Line Items]
Total	$ 125,000,000		125,000,000
Stated rate (as a percent)	4.18%
Effective Rate (as a percentage)	4.21%
Senior unsecured notes, Series D | Senior notes
Debt Instrument [Line Items]
Total	$ 115,000,000		115,000,000
Stated rate (as a percent)	4.08%
Effective Rate (as a percentage)	4.11%
Senior unsecured notes, Series E | Senior notes
Debt Instrument [Line Items]
Total	$ 160,000,000		160,000,000
Stated rate (as a percent)	4.26%
Effective Rate (as a percentage)	4.27%
Senior unsecured notes, Series F | Senior notes
Debt Instrument [Line Items]
Total	$ 175,000,000		175,000,000
Stated rate (as a percent)	4.44%
Effective Rate (as a percentage)	4.45%
Senior unsecured notes, Series G | Senior notes
Debt Instrument [Line Items]
Total	$ 100,000,000		0
Stated rate (as a percent)	3.61%	3.61%
Effective Rate (as a percentage)	4.89%
Face amount		$ 100,000,000
Senior unsecured notes, Series H | Senior notes
Debt Instrument [Line Items]
Total	$ 75,000,000		0
Stated rate (as a percent)	3.73%	3.73%
Effective Rate (as a percentage)	5.00%
Face amount		$ 75,000,000
Unsecured revolving credit facility | Revolving credit facility
Debt Instrument [Line Items]
Unsecured revolving credit facility, net	$ 0		0
Effective Rate (as a percentage)	2.03%
Unsecured revolving credit facility | Revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percentage)	1.10%
Unsecured term loan facilities | Revolving credit facility
Debt Instrument [Line Items]
Unsecured revolving credit facility, net	$ 215,000,000		265,000,000
Effective Rate (as a percentage)	3.77%
Unsecured term loan facilities | Revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percentage)	1.20%
Unsecured term loan facility | Revolving credit facility
Debt Instrument [Line Items]
Unsecured revolving credit facility, net	$ 175,000,000		$ 0
Effective Rate (as a percentage)	2.99%
Unsecured term loan facility | Revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percentage)	1.50%

Debt - Aggregate Required Princ

Debt - Aggregate Required Principal Payments (Details) $ in Thousands	Sep. 30, 2020USD ($)
Amortization
2020	$ 998
2021	4,090
2022	5,628
2023	7,876
2024	7,958
Thereafter	25,909
Total	52,459
Maturities
2020	0
2021	0
2022	0
2023	0
2024	77,675
Thereafter	1,842,748
Total	1,920,423
Total
2020	998
2021	4,090
2022	5,628
2023	7,876
2024	85,633
Thereafter	1,868,657
Total	$ 1,972,882

Debt - Deferred Financing Costs

Debt - Deferred Financing Costs, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Debt Instrument [Line Items]
Financing costs	$ 28,814		$ 28,814		$ 25,315
Less: accumulated amortization	(16,848)		(16,848)		(13,863)
Total deferred financing costs, net	11,966		11,966		11,452
Amortization expense related to deferred financing costs	1,000	$ 900	3,000	$ 2,900
Revolving credit facility | Unsecured revolving credit facility
Debt Instrument [Line Items]
Net deferred financing costs	$ 2,700		$ 2,700		$ 4,200

Debt - Unsecured Revolving Cred

Debt - Unsecured Revolving Credit and Term Loan Facilities (Details)	Mar. 19, 2020USD ($)option	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowings				$ 0	$ 0
Unsecured Revolving Credit Facility and Term Loan | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,315,000,000
Unsecured revolving credit facility, higher borrowing capacity option	1,750,000,000
Unsecured revolving credit facility | Revolving Credit Facility
Line of Credit Facility [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
Term loan facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 215,000,000
Outstanding borrowings				215,000,000	265,000,000
Unsecured term loan facility | Revolving Credit Facility
Line of Credit Facility [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
Minimum | Unsecured revolving credit facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Extension fee, as a percent of outstanding commitments under revolving credit facility (percentage)	0.0625%
Maximum | Unsecured revolving credit facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Extension fee, as a percent of outstanding commitments under revolving credit facility (percentage)	0.075%
Forecast | Unsecured term loan facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Prepayment fee, percent of principal amount prepaid		1.00%	2.00%

Debt - Senior Unsecured Notes (

Debt - Senior Unsecured Notes (Details) - Senior notes - USD ($)	Mar. 17, 2020	Sep. 30, 2020
Series G and Series H Senior Unsecured Notes
Debt Instrument [Line Items]
Face amount	$ 175,000,000
Issue price, as a percent of aggregate principal amount	100.00%
Senior unsecured notes, Series G
Debt Instrument [Line Items]
Face amount	$ 100,000,000
Stated rate (as a percent)	3.61%	3.61%
Senior unsecured notes, Series H
Debt Instrument [Line Items]
Face amount	$ 75,000,000
Stated rate (as a percent)	3.73%	3.73%

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued capital expenditures	$ 63,984	$ 90,910
Accounts payable and accrued expenses	34,114	35,084
Interest rate swap agreements liability	10,222	13,330
Accrued interest payable	2,792	3,699
Due to affiliated companies	806	763
Total accounts payable and accrued expenses	$ 111,918	$ 143,786

Financial Instruments and Fai_3

Financial Instruments and Fair Values - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	$ 10,222,000		$ 10,222,000		$ 13,330,000
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	10,300,000		10,300,000
Designated as Hedging Instrument | Cash Flow Hedging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loss to be reclassified into interest expense within the next 12 months			(11,500,000)
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate notional value	265,000,000		265,000,000		390,000,000
Net unrealized gain (loss)	2,900,000	$ (5,900,000)	(13,400,000)	$ (25,400,000)
Accounts payable and accrued expenses | Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	10,200,000		10,200,000		$ 13,300,000
LIBOR | Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap, Three Month LIBOR, 2.9580%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount	$ 125,000,000		125,000,000
Payment of termination settlement fee			$ 20,300,000

Financial Instruments and Fai_4

Financial Instruments and Fair Values - Summary of the Terms of Agreements and the Fair Value of Derivative Financial Instruments (Details) - Cash Flow Hedging - Designated as Hedging Instrument - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Asset	$ 0	$ 0
Liability	(10,222,000)	(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	(10,222,000)	(4,247,000)
LIBOR | Interest Rate Swap, Three Month LIBOR, 2.9580%
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 - Effect of Derivative Financial Instruments Designated as Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ 64	$ (6,256)	$ (19,340)	$ (25,992)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(2,873)	(319)	(5,986)	(637)
Interest expense	(23,360)	(19,426)	(66,906)	(60,712)
Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	64	(6,256)	(19,340)	(25,992)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(2,873)	(319)	(5,986)	(637)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated other comprehensive income (loss) | Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (2,873)	$ (319)	$ (5,986)	$ (637)

Financial Instruments and Fai_6

Financial Instruments and Fair Values - Summary of the Carrying and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	$ 10,222	$ 13,330
Mortgages | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	603,178	605,542
Mortgages | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	636,032	629,609
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Senior notes | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	973,106
Senior unsecured notes - Series A, B, C, D, E, F, G and H | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,055,971
Senior unsecured notes - Series A, B, C, D, E and F | Senior notes | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		798,392
Senior unsecured notes - Series A, B, C, D, E and F | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		843,394
Fair Value, Inputs, Level 1 | Mortgages | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Fair Value, Inputs, Level 1 | Senior unsecured notes - Series A, B, C, D, E, F, G and H | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0
Fair Value, Inputs, Level 1 | Senior unsecured notes - Series A, B, C, D, E and F | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Fair Value, Inputs, Level 2 | Mortgages | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Fair Value, Inputs, Level 2 | Senior unsecured notes - Series A, B, C, D, E, F, G and H | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0
Fair Value, Inputs, Level 2 | Senior unsecured notes - Series A, B, C, D, E and F | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Fair Value, Inputs, Level 3 | Mortgages | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	636,032	629,609
Fair Value, Inputs, Level 3 | Senior unsecured notes - Series A, B, C, D, E, F, G and H | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,055,971
Fair Value, Inputs, Level 3 | Senior unsecured notes - Series A, B, C, D, E and F | Senior notes | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		843,394
Revolving Credit Facility | Unsecured term loan facilities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	387,309	264,640
Revolving Credit Facility | Unsecured term loan facilities | 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 | Fair Value, Inputs, Level 1 | Unsecured term loan facilities | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Revolving Credit Facility | Fair Value, Inputs, Level 2 | Unsecured term loan facilities | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Revolving Credit Facility | Fair Value, Inputs, Level 3 | Unsecured term loan facilities | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	390,000	265,000
Interest Rate Swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	10,300
Interest Rate Swap | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	10,222	13,330
Interest Rate Swap | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	10,222	13,330
Interest Rate Swap | Fair Value, Inputs, 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 Swap | Fair Value, Inputs, 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	10,222	13,330
Interest Rate Swap | Fair Value, Inputs, 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	Sep. 30, 2020USD ($)property	Dec. 31, 2019USD ($)
Operating Leases [Line Items]
Number of properties subject to ground leases | property	3
Right-of-use assets	$ 29,154	$ 29,307
Lease liabilities	$ 29,154	$ 29,307
Weighted average discount rate	4.50%
Weighted average remaining lease term (in years)	49 years 7 months 6 days
Minimum
Operating Leases [Line Items]
Term of lease	1 year
Maximum
Operating Leases [Line Items]
Term of lease	21 years

Leases - Components of Rental R

Leases - Components of Rental Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Fixed payments	$ 122,976	$ 129,030	$ 375,882	$ 380,647
Variable payments	16,933	21,195	50,139	54,066
Total rental revenue	$ 139,909	$ 150,225	$ 426,021	$ 434,713

Leases - Future Contractual Min

Leases - Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received (Details) $ in Thousands	Sep. 30, 2020USD ($)
Leases [Abstract]
Remainder of 2020	$ 126,997
2021	502,160
2022	484,131
2023	459,992
2024	423,039
Thereafter	2,139,096
Total future minimum lease payments on non-cancellable operating leases to be received	$ 4,135,415

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments on Ground Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Remainder of 2020	$ 380
2021	1,518
2022	1,518
2023	1,518
2024	1,518
Thereafter	66,780
Total undiscounted cash flows	73,232
Present value discount	(44,078)
Ground lease liabilities	$ 29,154	$ 29,307

Commitments and Contingencies

Commitments and Contingencies - Legal Proceedings (Details) - New York State Supreme Court, New York County $ in Millions	Aug. 26, 2020USD ($)	Oct. 31, 2014participant
Loss Contingencies [Line Items]
Number of participants opting out of settlement | participant		12
Amount awarded to claimants | $	$ 1.2
Interest period (in years)	7 years

Commitments and Contingencies_2

Commitments and Contingencies - Unfunded Capital Expenditures (Details) $ in Millions	Sep. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Estimated capital expenditures to be incurred	$ 130.1

Capital - Additional Informatio

Capital - Additional Information and Private Perpetual Preferred Units (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	May 16, 2019
Shares and Units [Abstract]
OP units outstanding (in shares)	288,375,949		288,375,949
Dividends on common stock received until performance criteria met for LTIP units (as a percent)	10.00%		10.00%
Dividends on common stock received after performance criteria met for LTIP units (as a percent)	90.00%		90.00%
Dividends on common stock received in periods after performance criteria met for LTIP units (as a percent)	100.00%		100.00%
Dividends declared (in USD per share)	$ 0	$ 0.105	$ 0.210	$ 0.315
2019 Plan
Shares and Units [Abstract]
Number of shares authorized under the plan (in shares)	11,000,000		11,000,000			11,000,000
Empire State Realty Trust
Shares and Units [Abstract]
OP units owned by the Company (in shares)	172,992,089		172,992,089
Other Partners, Certain Directors, Officers And Other Members Of Executive Management
Shares and Units [Abstract]
OP units not owned by the Company (in shares)	115,383,860		115,383,860
Empire State Realty OP | Empire State Realty Trust
Shares and Units [Abstract]
OP units owned by the Company (as a percent)			60.00%
Empire State Realty OP | Other Partners, Certain Directors, Officers And Other Members Of Executive Management
Shares and Units [Abstract]
OP units not owned by the Company (as a percent)			40.00%
Private Perpetual Preferred Units, Series 2019
Shares and Units [Abstract]
Private perpetual preferred units, issued (in shares)	4,664,038		4,664,038		4,610,383
Private perpetual preferred units, liquidation preference (in USD per share)	$ 13.52		$ 13.52		$ 13.52
Preferred units cumulative cash distributions (in USD per share)	$ 0.70		$ 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		1,560,360
Private perpetual preferred units issued during period (in shares)			1,560,360
Private perpetual preferred units, liquidation preference (in USD per share)	$ 16.62		$ 16.62		$ 16.62
Dividends declared (in USD per share)			$ 0.60

Capital - Equity Securities Rep

Capital - Equity Securities Repurchased (Details) - USD ($)	1 Months Ended
	Oct. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Jul. 31, 2020
Equity, Class of Treasury Stock [Line Items]
Stock repurchase authorized amount		$ 500,000,000
Total Number of Shares Purchased (in shares)		477,620	0	656,318
Average Price Paid per Share (in usd per share)		$ 6.14	$ 0	$ 6.72
Maximum Approximate Dollar Value Available for Future Purchase		$ 378,050,000	$ 380,982,000	$ 380,982,000
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased (in shares)	1,952,013
Average Price Paid per Share (in usd per share)	$ 6.21
Maximum Approximate Dollar Value Available for Future Purchase	$ 365,934,000

Capital - Distributions (Detail

Capital - Distributions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity [Abstract]
Distributions paid to OP unitholders	$ 0	$ 31.9	$ 62.2	$ 95.7
Distributions paid to preferred unitholders	$ 1.1	$ 0.2	$ 3.1	$ 0.7

Capital - Incentive and Share-b

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

1 Months Ended

3 Months Ended

6 Months Ended

9 Months Ended

Aug. 31, 2020USD ($)shares

Jun. 30, 2020USD ($)shares

May 31, 2020USD ($)vesting_installmentshares

Mar. 31, 2020USD ($)vesting_installmentshares

Mar. 31, 2019USD ($)vesting_installmentshares

Sep. 30, 2020USD ($)shares

Jun. 30, 2020

Mar. 31, 2020

Sep. 30, 2019USD ($)

Oct. 31, 2019USD ($)vesting_installmentshares

Sep. 30, 2020USD ($)$ / sharesshares

Sep. 30, 2019USD ($)

May 16, 2019shares

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

Retirement age

65 years

60 years

Expected volatility rate look-back period (in years)

6 years

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

$ 5.43

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 | $

$ 0.4

$ 0.3

$ 2.3

$ 1.8

Unrecognized compensation expense | $

1.7

$ 1.7

Unrecognized compensation expense, period for recognition

2 years 3 months 18 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 | $

5.1

$ 3.4

$ 17.9

$ 13.6

Unrecognized compensation expense | $

$ 31.4

$ 31.4

Unrecognized compensation expense, period for recognition

2 years 3 months 18 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 | $

$ 28.1

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

$ 5.43

Dividend rate (as a percent)

3.70%

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%

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]

Shares granted (in shares)

63,229

113,971

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

$ 0.4

$ 2.3

Award vesting period

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]

Shares granted (in shares)

61,432

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

$ 2

Award vesting period

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]

Shares granted (in shares)

502,475

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

$ 2.3

Award vesting period

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]

Shares granted (in shares)

113,383

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

$ 0.9

Award vesting period

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]

Shares granted (in shares)

158,806

Time Restricted Shares | 2013 Plan Units

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

Shares granted (in shares)

69,358

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

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

Shares granted (in 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]

Shares granted (in shares)

624,380

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

$ 4.4

Award vesting period

3 years

Vesting percentage of award face amount

125.00%

125.00%

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

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

Shares granted (in 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]

Shares granted (in shares)

334,952

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

$ 4.6

Award vesting period

3 years

Vesting percentage of award face amount

125.00%

125.00%

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

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

Shares granted (in shares)

23,049

26,056

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

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

Shares granted (in shares)

601,331

308,896

Award vesting period

3 years

3 years

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

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

Number of vesting installments | vesting_installment

2

2

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

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

Shares granted (in shares)

116,927

3,358,767

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

$ 0.5

$ 14

Reduction of grants (in 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]

Shares granted (in shares)

1,806,520

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

$ 12.8

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

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

Shares granted (in shares)

25,242

171,153

76,718

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

$ 0.2

$ 1.1

$ 1.1

Award vesting period

3 years

3 years

Number of vesting installments | vesting_installment

2

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)

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)

11,000,000

11,000,000

11,000,000

Number of shares that remain available for future issuance (in 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

60 years

Minimum | Long-Term Incentive Plan Units and Restricted Stock

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

Expected term

2 years

Minimum | Time Based Long-Tern Incentive Plan Unit

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

Award vesting period

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

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

65 years

Maximum | Long-Term Incentive Plan Units and Restricted Stock

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

Expected term

5 years 6 months

Maximum | Time Based Long-Tern Incentive Plan Unit

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

Award vesting period

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

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)	9 Months Ended
	Sep. 30, 2020$ / sharesshares
Weighted Average Grant Fair Value
Beginning balance, Unvested (in USD per share) | $ / shares	$ 9.73
Vested (in USD per share) | $ / shares	14.04
Granted (in USD per share) | $ / shares	5.43
Forfeited or unearned (in USD per share) | $ / shares	7.57
Ending balance, Unvested (in USD per share) | $ / shares	$ 6.93
Restricted Stock
Restricted Stock and LTIP Units
Beginning balance, Unvested (in shares)	118,918
Vested (in shares)	(57,599)
Granted (in shares)	161,449
Forfeited or unearned (in shares)	(1,136)
Ending balance, Unvested (in shares)	221,632
LTIP Units
Restricted Stock and LTIP Units
Beginning balance, Unvested (in shares)	5,986,569
Vested (in shares)	(1,052,692)
Granted (in shares)	5,011,693
Forfeited or unearned (in shares)	(2,201,453)
Ending balance, Unvested (in shares)	7,744,117

Capital - Earnings Per Unit (De

Capital - Earnings Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income (loss)	$ (12,269)	$ 26,784	$ (23,599)	$ 55,570
Private perpetual preferred unit distributions	(1,050)	(234)	(3,147)	(702)
Earnings allocated to unvested units	(342)	(243)	(985)	(646)
Net income (loss) attributable to common unitholders - basic and diluted	$ (13,661)	$ 26,307	$ (27,731)	$ 54,222
Denominator:
Weighted average units outstanding - basic (in units)	280,940,000	298,151,000	285,640,000	298,117,000
Effect of dilutive securities:
Stock-based compensation plans (in units)	0	0	0	0
Weighted average units outstanding - diluted (in units)	280,940,000	298,151,000	285,640,000	298,117,000
Earnings per share:
Basic (in USD per unit)	$ (0.05)	$ 0.09	$ (0.10)	$ 0.18
Diluted (in USD per unit)	$ (0.05)	$ 0.09	$ (0.10)	$ 0.18
Antidilutive securities (in units)	0	452,457	169,848	288,053

Related Party Transactions (Det

Related Party Transactions (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)ft²property	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²property	Sep. 30, 2019USD ($)
Related Party Transaction [Line Items]
Area of real estate property (in square feet) | ft²	10,100,000		10,100,000
Affliliated entity | Supervisory fee revenue
Related Party Transaction [Line Items]
Revenue from related parties	$ 0.2	$ 0.2	$ 0.7	$ 0.7
Affliliated entity | Property management fee revenue
Related Party Transaction [Line Items]
Revenue from related parties	0.1	0.1	0.2	0.2
Affliliated entity | Leased space rental
Related Party Transaction [Line Items]
Revenue from related parties	$ 0.1	$ 0.1	$ 0.2	$ 0.2
Number of properties | property	1		1
Lease cancellation, notice period (in days)			90 days
Undivided Interest
Related Party Transaction [Line Items]
Area of real estate property (in square feet) | ft²	5,447		5,447
Chairman emeritus | Leased space rental
Related Party Transaction [Line Items]
Percentage of lease space occupied by Chairman emeritus and employee			15.00%

Segment Reporting - Narrative

Segment Reporting - Narrative (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)segment	Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				2
Impairment charges	$ 2,103		$ 0	$ 6,204	$ 0
Real estate
Segment Reporting Information [Line Items]
Impairment charges	$ 2,100	$ 4,100		$ 6,200

Segment Reporting - Components

Segment Reporting - Components of Segment Profit for Each Segment (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenues:
Rental revenue	$ 139,909		$ 150,225	$ 426,021	$ 434,713
Intercompany rental revenue	0		0	0	0
Observatory revenue	4,419		37,575	24,049	91,039
Lease termination fees	331		2,361	1,575	3,112
Third-party management and other fees	283		304	930	955
Other revenue and fees	1,633		2,408	5,254	6,591
Total revenues	146,575		192,873	457,829	536,410
Operating expenses:
Property operating expenses	33,836		47,894	105,054	131,076
Intercompany rent expense	0		0	0	0
Ground rent expense	2,331		2,331	6,994	6,994
General and administrative expenses	14,517		14,421	48,617	44,445
Observatory expenses	5,931		9,089	18,087	25,024
Real estate taxes	31,196		29,599	90,029	86,098
Impairment charges	2,103		0	6,204	0
Depreciation and amortization	44,733		44,260	143,609	135,179
Total operating expenses	134,647		147,594	418,594	428,816
Total operating income	11,928		45,279	39,235	107,594
Other income (expense):
Interest income	366		2,269	2,529	9,907
Interest expense	(23,360)		(19,426)	(66,906)	(60,712)
Loss on early extinguishment of debt	0		0	(86)	0
IPO litigation expense	(1,165)		0	(1,165)	0
Income (loss) before income taxes	(12,231)		28,122	(26,393)	56,789
Income tax (expense) benefit	(38)		(1,338)	2,794	(1,219)
Net income (loss)	(12,269)		26,784	(23,599)	55,570
Segment assets	4,010,714		3,925,317	4,010,714	3,925,317	$ 3,931,834
Expenditures for segment assets	31,347		61,276	80,251	181,568
Real Estate
Operating expenses:
Impairment charges	2,100	$ 4,100		6,200
Operating Segments | Real Estate
Revenues:
Rental revenue	139,909		150,225	426,021	434,713
Intercompany rental revenue	(2,233)		23,242	13,356	58,754
Lease termination fees	331		2,361	1,575	3,112
Third-party management and other fees	283		304	930	955
Other revenue and fees	1,633		2,408	5,254	6,591
Total revenues	139,923		178,540	447,136	504,125
Operating expenses:
Property operating expenses	33,836		47,894	105,054	131,076
Ground rent expense	2,331		2,331	6,994	6,994
General and administrative expenses	14,517		14,421	48,617	44,445
Real estate taxes	31,196		29,599	90,029	86,098
Impairment charges	2,103			6,204
Depreciation and amortization	44,679		44,253	143,522	135,157
Total operating expenses	128,662		138,498	400,420	403,770
Total operating income	11,261		40,042	46,716	100,355
Other income (expense):
Interest income	360		2,269	2,438	9,907
Interest expense	(23,360)		(19,426)	(66,906)	(60,712)
Loss on early extinguishment of debt	0			(86)
IPO litigation expense	(1,165)			(1,165)
Income (loss) before income taxes	(12,904)		22,885	(19,003)	49,550
Income tax (expense) benefit	(196)		(267)	(692)	(762)
Net income (loss)	(13,100)		22,618	(19,695)	48,788
Segment assets	3,771,476		3,659,592	3,771,476	3,659,592
Expenditures for segment assets	30,831		42,901	77,503	134,865
Operating Segments | Observatory
Revenues:
Intercompany rental revenue	0		0	0	0
Observatory revenue	4,419		37,575	24,049	91,039
Total revenues	4,419		37,575	24,049	91,039
Operating expenses:
Intercompany rent expense	(2,233)		23,242	13,356	58,754
General and administrative expenses	0		0	0	0
Observatory expenses	5,931		9,089	18,087	25,024
Impairment charges	0			0
Depreciation and amortization	54		7	87	22
Total operating expenses	3,752		32,338	31,530	83,800
Total operating income	667		5,237	(7,481)	7,239
Other income (expense):
Interest income	6		0	91	0
Interest expense	0		0	0	0
Loss on early extinguishment of debt	0			0
IPO litigation expense	0			0
Income (loss) before income taxes	673		5,237	(7,390)	7,239
Income tax (expense) benefit	158		(1,071)	3,486	(457)
Net income (loss)	831		4,166	(3,904)	6,782
Segment assets	239,238		265,725	239,238	265,725
Expenditures for segment assets	516		18,375	2,748	46,703
Intersegment Elimination
Revenues:
Intercompany rental revenue	2,233		(23,242)	(13,356)	(58,754)
Total revenues	2,233		(23,242)	(13,356)	(58,754)
Operating expenses:
Intercompany rent expense	2,233		(23,242)	(13,356)	(58,754)
General and administrative expenses	0		0	0	0
Impairment charges	0			0
Depreciation and amortization	0		0	0	0
Total operating expenses	2,233		(23,242)	(13,356)	(58,754)
Total operating income	0		0	0	0
Other income (expense):
Interest income	0		0	0	0
Interest expense	0		0	0	0
Loss on early extinguishment of debt	0			0
IPO litigation expense	0			0
Income (loss) before income taxes	0		0	0	0
Income tax (expense) benefit	0		0	0	0
Net income (loss)	0		0	0	0
Segment assets	0		0	0	0
Expenditures for segment assets	$ 0		$ 0	$ 0	$ 0