Empire State Realty OP (FISK) 10-Q 5 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Jul. 28, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
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	850-2600
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	2021
Document Fiscal Period Focus	Q2
Series ES operating partnership units
Document Information [Line Items]
Title of 12(b) Security	Series ES operating partnership units
Trading Symbol	ESBA
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		22,913,843
Series 60 operating partnership units
Document Information [Line Items]
Title of 12(b) Security	Series 60 operating partnership units
Trading Symbol	OGCP
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		6,112,894
Series 250 operating partnership units
Document Information [Line Items]
Title of 12(b) Security	Series 250 operating partnership units
Trading Symbol	FISK
Security Exchange Name	NYSEArca
Entity Common Stock, Shares Outstanding		3,045,709

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Commercial real estate properties, at cost:
Land	$ 201,196	$ 201,196
Development costs	8,064	7,966
Building and improvements	2,959,259	2,924,804
Commercial real estate properties, at cost	3,168,519	3,133,966
Less: accumulated depreciation	(1,007,429)	(941,612)
Commercial real estate properties, net	2,161,090	2,192,354
Cash and cash equivalents	540,604	526,714
Restricted cash	37,966	41,225
Tenant and other receivables	19,238	21,541
Deferred rent receivables	231,143	222,508
Prepaid expenses and other assets	71,399	77,182
Deferred costs, net	200,735	203,853
Acquired below-market ground leases, net	340,820	344,735
Right of use assets	28,998	29,104
Goodwill	491,479	491,479
Total assets	4,123,472	4,150,695
Liabilities:
Mortgage notes payable, net	774,612	775,929
Senior unsecured notes, net	973,267	973,159
Unsecured term loan facilities, net	387,954	387,561
Unsecured revolving credit facility	0	0
Accounts payable and accrued expenses	89,254	103,203
Acquired below-market leases, net	28,532	31,705
Ground lease liabilities	28,998	29,104
Deferred revenue and other liabilities	81,762	88,319
Tenants’ security deposits	25,885	30,408
Total liabilities	2,390,264	2,419,388
Commitments and contingencies
Capital:
Total capital	1,733,208	1,731,307
Total liabilities and capital	4,123,472	4,150,695
Private perpetual preferred units, series 2019
Capital:
Private perpetual preferred units	21,936	21,936
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 (2,857 and 2,853 general partner operating partnership units and 170,543 and 168,713 limited partner operating partnership units outstanding in 2021 and 2020, respectively)	1,055,659	1,055,249
Limited partner operating partnership units	650,473	648,543
Series ES operating partnership units
Capital:
Limited partner operating partnership units	(1,692)	(1,348)
Series 60 operating partnership units
Capital:
Limited partner operating partnership units	(789)	(721)
Series 250 operating partnership units
Capital:
Limited partner operating partnership units	$ (383)	$ (356)

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
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	4,664,000
Private perpetual preferred units, outstanding (in shares)	4,664,000	4,664,000
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)	1,560,000	1,560,000
Private perpetual preferred units, outstanding (in shares)	1,560,000	1,560,000
Series PR Operating Partnership Units
Capital
Limited partner operating partnership units, outstanding (in shares)	80,241,000	80,355,000
Series ES operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	22,923,000	23,678,000
Series 60 operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	6,112,000	6,425,000
Series 250 operating partnership units
Capital
Limited partner operating partnership units, outstanding (in shares)	3,045,000	3,255,000
ESRT | Series PR Operating Partnership Units
Capital
General partner operating partnership units, outstanding (in shares)	2,857,000	2,853,000
Limited partner operating partnership units, outstanding (in shares)	170,543,000	168,713,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Rental revenue	$ 140,797	$ 137,999	$ 281,028	$ 286,112
Observatory revenue	8,359	86	10,962	19,630
Lease termination fees	3,339	1,033	4,628	1,244
Third-party management and other fees	327	301	603	647
Other revenue and fees	586	1,611	1,491	3,621
Total revenues	153,408	141,030	298,712	311,254
Operating expenses:
Property operating expenses	28,793	29,750	59,072	71,218
Ground rent expenses	2,332	2,332	4,663	4,663
General and administrative expenses	14,089	18,149	27,942	34,100
Observatory expenses	5,268	4,002	9,856	12,156
Real estate taxes	31,354	29,579	62,801	58,833
Impairment charges	0	4,101	0	4,101
Depreciation and amortization	45,088	52,783	89,545	98,876
Total operating expenses	126,924	140,696	253,879	283,947
Total operating income (loss)	26,484	334	44,833	27,307
Other income (expense):
Interest income	164	1,526	286	2,163
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Loss on early extinguishment of debt	0	0	(214)	(86)
Income (loss) before income taxes	3,226	(22,068)	(2,071)	(14,162)
Income tax benefit	1,185	2,450	3,291	2,832
Net income (loss)	4,411	(19,618)	1,220	(11,330)
Private perpetual preferred unit distributions	(1,051)	(1,047)	(2,101)	(2,097)
Net income (loss) attributable to common unitholders	$ 3,360	$ (20,665)	$ (881)	$ (13,427)
Total weighted average units:
Basic (in shares)	277,893	283,384	277,887	288,015
Diluted (in shares)	278,436	283,384	277,887	288,015
Earnings (loss) per unit attributable to common unitholders:
Basic (in USD per share)	$ 0.01	$ (0.07)	$ 0	$ (0.05)
Diluted (in USD per share)	0.01	(0.07)	0	(0.05)
Dividends per unit ((in USD per share)	$ 0.035	$ 0.105	$ 0.035	$ 0.210

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 4,411	$ (19,618)	$ 1,220	$ (11,330)
Other comprehensive income (loss):
Unrealized gain (loss) on valuation of interest rate swap agreements	(95)	(1,709)	(36)	(19,404)
Less: amount reclassified into interest expense	2,898	2,317	5,767	3,113
Other comprehensive income (loss)	2,803	608	5,731	(16,291)
Comprehensive income (loss)	$ 7,214	$ (19,010)	$ 6,951	$ (27,621)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Capital (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	$ 1,731,195	$ 1,849,876	$ 1,731,307	$ 1,947,913
Issuance of private perpetual preferred in exchange for common units	0	0	0	0
Conversion of operating partnership units to ESRT Partner's Capital	$ 0	0	0	0
Repurchases of common units (in shares)	0
Repurchases of common units	$ 0	(51,939)	(3,533)	(114,605)
Equity compensation	5,304	8,779	10,038	14,670
Distributions	(10,505)	(31,668)	(11,555)	(64,319)
Net income (loss)	4,411	(19,618)	1,220	(11,330)
Other comprehensive income (loss)	2,803	608	5,731	(16,291)
Ending balance	$ 1,733,208	$ 1,756,038	$ 1,733,208	$ 1,756,038
General Partner | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	172,332,000	177,128,000	171,565,000	181,894,000
Beginning balance	$ 1,053,495	$ 1,148,584	$ 1,055,249	$ 1,228,520
Conversion of operating partnership units to ESRT Partner's Capital (in shares)	1,074,000	2,717,000	2,140,000	4,376,000
Conversion of operating partnership units to ESRT Partner's Capital	$ 4,173	$ 13,955	$ 6,835	$ 21,517
Repurchases of common units (in shares)		(6,500,000)	(383,000)	(13,071,000)
Repurchases of common units		$ (51,939)	$ (3,533)	$ (114,605)
Equity compensation (in shares)	(6,000)	2,000	78,000	148,000
Equity compensation	$ 240	$ 231	$ 164	$ 385
Distributions	(6,063)	(18,194)	(6,063)	(37,181)
Net income (loss)	2,075	(12,793)	(546)	(8,298)
Other comprehensive income (loss)	$ 1,739	$ 377	$ 3,553	$ (10,117)
Ending balance (in shares)	173,400,000	173,347,000	173,400,000	173,347,000
Ending balance	$ 1,055,659	$ 1,080,221	$ 1,055,659	$ 1,080,221
Limited Partners | Series PR Operating Partnership Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	80,656,000	84,900,000	80,355,000	81,388,000
Beginning balance	$ 650,254	$ 666,778	$ 648,543	$ 680,580
Issuance of private perpetual preferred in exchange for common units (in shares)				(97,000)
Issuance of private perpetual preferred in exchange for common units				$ (800)
Conversion of operating partnership units to ESRT Partner's Capital (in shares)	(521,000)	(1,779,000)	(863,000)	(2,673,000)
Conversion of operating partnership units to ESRT Partner's Capital	$ (4,212)	$ (13,875)	$ (6,958)	$ (21,291)
Equity compensation (in shares)	106,000	(355,000)	749,000	4,148,000
Equity compensation	$ 5,064	$ 8,548	$ 9,874	$ 14,285
Distributions	(2,262)	(8,770)	(2,262)	(17,619)
Net income (loss)	887	(5,316)	(232)	(3,464)
Other comprehensive income (loss)	$ 742	$ 155	$ 1,508	$ (4,171)
Ending balance (in shares)	80,241,000	82,766,000	80,241,000	82,766,000
Ending balance	$ 650,473	$ 647,520	$ 650,473	$ 647,520
Limited Partners | Series ES Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	23,270,000	25,359,000	23,678,000	25,810,000
Beginning balance	$ (1,418)	$ 3,652	$ (1,348)	$ 7,262
Issuance of private perpetual preferred in exchange for common units (in shares)				43,000
Issuance of private perpetual preferred in exchange for common units				$ 11
Conversion of operating partnership units to ESRT Partner's Capital (in shares)	(347,000)	(830,000)	(755,000)	(1,324,000)
Conversion of operating partnership units to ESRT Partner's Capital	$ 17	$ (76)	$ 55	$ (180)
Distributions	(806)	(2,587)	(806)	(5,264)
Net income (loss)	282	(1,812)	(74)	(1,182)
Other comprehensive income (loss)	$ 233	$ 53	$ 481	$ (1,417)
Ending balance (in shares)	22,923,000	24,529,000	22,923,000	24,529,000
Ending balance	$ (1,692)	$ (770)	$ (1,692)	$ (770)
Limited Partners | Series 60 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	6,253,000	6,824,000	6,424,000	7,025,000
Beginning balance	$ (727)	$ 607	$ (721)	$ 1,593
Conversion of operating partnership units to ESRT Partner's Capital (in shares)	(141,000)	(48,000)	(312,000)	(249,000)
Conversion of operating partnership units to ESRT Partner's Capital	$ 15	$ (2)	$ 40	$ (33)
Distributions	(215)	(712)	(215)	(1,435)
Net income (loss)	79	(496)	(19)	(322)
Other comprehensive income (loss)	$ 59	$ 15	$ 126	$ (391)
Ending balance (in shares)	6,112,000	6,776,000	6,112,000	6,776,000
Ending balance	$ (789)	$ (588)	$ (789)	$ (588)
Limited Partners | Series 250 Operating Partnership Units Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	3,110,000	3,465,000	3,255,000	3,535,000
Beginning balance	$ (349)	$ 315	$ (356)	$ 807
Conversion of operating partnership units to ESRT Partner's Capital (in shares)	(65,000)	(60,000)	(210,000)	(130,000)
Conversion of operating partnership units to ESRT Partner's Capital	$ 7	$ (2)	$ 28	$ (13)
Distributions	(108)	(358)	(108)	(723)
Net income (loss)	37	(248)	(10)	(161)
Other comprehensive income (loss)	$ 30	$ 8	$ 63	$ (195)
Ending balance (in shares)	3,045,000	3,405,000	3,045,000	3,405,000
Ending balance	$ (383)	$ (285)	$ (383)	$ (285)
Private Perpetual Preferred Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	6,224,000	6,224,000	6,224,000	6,170,000
Beginning balance	$ 29,940	$ 29,940	$ 29,940	$ 29,151
Issuance of private perpetual preferred in exchange for common units (in shares)				54,000
Issuance of private perpetual preferred in exchange for common units				$ 789
Distributions	(1,051)	(1,047)	(2,101)	(2,097)
Net income (loss)	$ 1,051	$ 1,047	$ 2,101	$ 2,097
Ending balance (in shares)	6,224,000	6,224,000	6,224,000	6,224,000
Ending balance	$ 29,940	$ 29,940	$ 29,940	$ 29,940

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash Flows From Operating Activities
Net income (loss)	$ 1,220	$ (11,330)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	89,545	98,876
Impairment charges	0	4,101
Amortization of non-cash items within interest expense	5,398	4,233
Amortization of acquired above- and below-market leases, net	(1,371)	(2,274)
Amortization of acquired below-market ground leases	3,916	3,916
Straight-lining of rental revenue	(10,110)	(5,483)
Equity based compensation	10,038	14,670
Settlement of derivative contract	0	(20,281)
Loss on early extinguishment of debt	214	86
Increase (decrease) in cash flows due to changes in operating assets and liabilities:
Security deposits	(4,523)	20,570
Tenant and other receivables	2,303	(4,378)
Deferred leasing costs	(8,372)	(7,508)
Prepaid expenses and other assets	5,783	(2,657)
Accounts payable and accrued expenses	(5,232)	(9,099)
Deferred revenue and other liabilities	(5,080)	(9,019)
Net cash provided by operating activities	83,729	74,423
Cash Flows From Investing Activities
Development costs	(98)	(1,336)
Additions to building and improvements	(48,347)	(78,377)
Net cash used in investing activities	(48,445)	(79,713)
Cash Flows From Financing Activities
Repayment of mortgage notes payable	(2,026)	(1,950)
Proceeds from unsecured senior notes	0	175,000
Proceeds from unsecured term loan	0	175,000
Repayment of unsecured term loan	0	(50,000)
Proceeds from unsecured revolving credit facility	0	550,000
Deferred financing costs	(7,539)	(3,585)
Repurchases of common units	(3,533)	(114,605)
Distributions	(11,555)	(64,319)
Net cash (used in) provided by financing activities	(24,653)	665,541
Net increase in cash and cash equivalents and restricted cash	10,631	660,251
Cash and cash equivalents and restricted cash—beginning of period	567,939	271,597
Cash and cash equivalents and restricted cash—end of period	578,570	931,848
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	526,714	233,946
Restricted cash at beginning of period	41,225	37,651
Cash and cash equivalents at end of period	540,604	872,970
Restricted cash at end of period	37,966	58,878
Cash and cash equivalents and restricted cash	578,570	931,848
Supplemental disclosures of cash flow information:
Cash paid for interest	38,639	37,736
Cash paid for income taxes	299	910
Non-cash investing and financing activities:
Building and improvements included in accounts payable and accrued expenses	52,891	64,175
Write-off of fully depreciated assets	8,729	33,261
Derivative instruments at fair values included in accounts payable and accrued expenses	6,176	11,629
Conversion of limited partners' operating partnership units to ESRT partner's capital	6,835	21,517
Issuance of Series 2019 private perpetual preferred in exchange for common units	$ 0	$ 789

Description of Business and Org

Description of Business and Organization	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021, 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 June 30, 2021, 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 June 30, 2021, ESRT owned approximately 60.7% of our operating partnership units.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
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, 2020 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, 2020 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 Coronavirus 19 ("COVID-19") pandemic. Historically prior to the outbreak of the COVID-19 pandemic, 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 June 30, 2021 and December 31, 2020. 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. 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 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.

Deferred Costs, Acquired Lease

Deferred Costs, Acquired Lease Intangibles and Goodwill	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Leasing costs $ 205,599 $ 203,905 Acquired in-place lease value and deferred leasing costs 177,501 181,336 Acquired above-market leases 35,330 40,398 418,430 425,639 Less: accumulated amortization (226,021) (223,918) Total deferred costs, net, excluding net deferred financing costs $ 192,409 $ 201,721 At June 30, 2021 and December 31, 2020, $8.3 million and $2.1 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 sheets. Amortization expense related to deferred leasing costs and acquired deferred leasing costs was $6.1 million and $6.4 million for the three months ended June 30, 2021 and 2020, respectively, and $11.7 million and $12.3 million for the six months ended June 30, 2021 and 2020, respectively. Amortization expense related to acquired lease intangibles was $1.6 million and $2.4 million for the three months ended June 30, 2021 and 2020, respectively, and $3.3 million and $4.4 million for the six months ended June 30, 2021 and 2020, respectively. Amortizing acquired intangible assets and liabilities consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (56,096) (52,181) Acquired below-market ground leases, net $ 340,820 $ 344,735 June 30, 2021 December 31, 2020 Acquired below-market leases $ (75,082) $ (78,451) Less: accumulated amortization 46,550 46,746 Acquired below-market leases, net $ (28,532) $ (31,705) Rental revenue related to the amortization of below-market leases, net of above-market leases, was $0.7 million and $1.4 million for the three months ended June 30, 2021 and 2020, respectively, and $1.4 million and $2.3 million for the six months ended June 30, 2021 and 2020, respectively. As of June 30, 2021, 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 reportable 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. The analysis used a combination of the discounted cash flow method (a form of the income approach) utilizing Level 3 unobservable inputs and the guideline company method (a form of the market approach). Significant assumptions under the former included revenue and cost projections, weighted average cost of capital, long-term growth rate and income tax considerations while the latter included guideline company enterprise values, revenue multiples and control premium rates. Our methodology to review goodwill impairment, which included a significant amount of judgment and estimates, provided a reasonable basis to determine whether impairment had occurred. Based upon the results of the goodwill impairment test of the standalone Observatory reporting unit, which is after the intercompany rent expense paid to the Real Estate reporting unit, we

Debt

Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Debt	Debt Debt consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): Principal Balance As of June 30, 2021 June 30, 2021 December 31, 2020 Stated Effective (1) Maturity (2) Mortgage debt collateralized by: Fixed rate mortgage debt Metro Center $ 86,217 $ 87,382 3.59 % 3.66 % 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 % 4.73 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,078 37,477 4.01 % 4.21 % 1/5/2028 250 West 57th Street 180,000 180,000 2.83 % 3.21 % 12/1/2030 10 Bank Street 31,563 32,025 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 784,858 786,884 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 100,000 100,000 3.61 % 4.89 % 3/17/2032 Series H 75,000 75,000 3.73 % 5.00 % 3/17/2035 Unsecured term loan facility (4) 215,000 215,000 LIBOR plus 1.20% 3.57 % 3/19/2025 Unsecured revolving credit facility (4) — — LIBOR plus 1.30% — 3/31/2025 Unsecured term loan facility (4) 175,000 175,000 LIBOR plus 1.50% 3.63 % 12/31/2026 Total principal 2,149,858 2,151,884 Deferred financing costs, net (14,025) (15,235) Total $ 2,135,833 $ 2,136,649 ______________ (1) The effective rate is the yield as of June 30, 2021 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 June 30, 2021, we were in compliance with all debt covenants. Principal Payments Aggregate required principal payments at June 30, 2021 are as follows (amounts in thousands): Year Amortization Maturities Total 2021 $ 2,064 $ — $ 2,064 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 2025 5,826 315,000 320,826 Thereafter 20,084 1,707,747 1,727,831 Total $ 49,436 $ 2,100,422 $ 2,149,858 Deferred Financing Costs Deferred financing costs, net, consisted of the following at June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Financing costs $ 42,689 $ 35,365 Less: accumulated amortization (20,338) (17,998) Total deferred financing costs, net $ 22,351 $ 17,367 Amortization expense related to deferred financing costs was $1.1 million and $1.0 million for the three months ended June 30, 2021 and 2020, respectively, and $2.3 million and $2.0 million for the six months ended June 30, 2021 and 2020, respectively. Unsecured Revolving Credit and Term Loan Facilities As described more fully in our Form 10-Q for the quarterly period ended March 31, 2021 (the "Q1 2021 10-Q"), in Q1 2021,we entered into an amended senior unsecured credit facility (the "Credit Facility") with Bank of America, N.A., as administrative agent and the other lenders party thereto. The Credit Facility is in the initial maximum principal amount of up to $1.065 billion, which consists of $850.0 million revolving credit facility that matures on March 31, 2025, and a $215.0 million term loan facility that matures on March 19, 2025. As of June 30, 2021, we had no borrowings under the revolving credit facility and $215.0 million under the term loan facility. Additionally, as described more fully in the Q1 2021 10-Q, we have outstanding a senior unsecured term loan facility (the "Term Loan Facility") that we entered into on March 19, 2020 with Wells Fargo Bank, National Association, as administrative agent, and the other lenders party thereto. The Term loan Facility is in the original principal amount of $175.0 million and matures on December 31, 2026. As of June 30, 2021, our borrowings amounted to $175.0 million under the Term Loan Facility. 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. Both facilities also require 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 agreements governing both facilities also contain 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 June 30, 2021, we were in compliance with the covenants. Senior Unsecured Notes The terms of the senior unsecured notes 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 agreements also contain 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 June 30, 2021, we were in compliance with the covenants under the outstanding senior unsecured notes.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Accrued capital expenditures $ 52,891 $ 58,057 Accounts payable and accrued expenses 26,012 32,309 Interest rate swap agreements liability 6,176 8,849 Accrued interest payable 3,392 3,219 Due to affiliated companies 783 769 Total accounts payable and accrued expenses $ 89,254 $ 103,203

Financial Instruments and Fair

Financial Instruments and Fair Values	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021, the fair value of the derivative in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to the agreement was $6.2 million. If we had breached any of these provisions at June 30, 2021, we could have been required to settle our obligation under the agreement at its termination value of $6.2 million. As of June 30, 2021 and December 31, 2020, we had an interest rate LIBOR swap with an aggregate notional value of $265.0 million and $265.0 million, respectively. The notional value does not represent exposure to credit, interest rate or market risks. As of June 30, 2021 and December 31, 2020, the fair value of our derivative instrument amounted to $(6.2) million and $(8.8) million, respectively, which is included in accounts payable and accrued expenses on the condensed consolidated balance sheets. This interest rate swap has been designated as a cash flow hedge and hedges the variability in future cash flows associated with our existing variable-rate term loan facilities. As of June 30, 2021 and 2020, our cash flow hedge is deemed highly effective and a net unrealized gain (loss) of $2.8 million and $0.6 million for the three months ended June 30, 2021 and 2020, respectively, and a net unrealized gain (loss) of $5.7 million and $(16.3) million for the six months ended June 30, 2021 and 2020, respectively, relating to both active and terminated hedges of interest rate risk, are reflected in the condensed consolidated statements of comprehensive income (loss). 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 June 30, 2021 and December 31, 2020 (dollar amounts in thousands): June 30, 2021 December 31, 2020 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 $ — $ (6,176) $ — $ (8,849) 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 six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended Six Months Ended Effects of Cash Flow Hedges June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Amount of gain (loss) recognized in other comprehensive income (loss) $ (95) $ (1,709) $ (36) $ (19,404) Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense (2,898) (2,317) (5,767) (3,113) 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 six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended Six Months Ended Effects of Cash Flow Hedges June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Total interest (expense) presented in the condensed consolidated statements of operations in which the effects of cash flow hedges are recorded $ (23,422) $ (23,928) $ (46,976) $ (43,546) Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense (2,898) (2,317) (5,767) (3,113) Fair Valuation The estimated fair values at June 30, 2021 and December 31, 2020 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 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 and unsecured revolving credit facility 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 June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swap included in accounts payable and accrued expenses $ 6,176 $ 6,176 $ — $ 6,176 $ — Mortgage notes payable 774,612 791,438 — — 791,438 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,267 1,003,628 — — 1,003,628 Unsecured term loan facilities 387,954 390,000 — — 390,000 December 31, 2020 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swap included in accounts payable and accrued expenses $ 8,849 $ 8,849 $ — $ 8,849 $ — Mortgage notes payable 775,929 808,294 — — 808,294 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,159 1,039,857 — — 1,039,857 Unsecured term loan facilities 387,561 390,000 — — 390,000

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one Rental revenue includes fixed and variable payments. Fixed payments primarily relate to base rent and variable payments primarily relate to tenant expense reimbursements for certain property operating costs. The components of rental revenue for the three and six months ended June 30, 2021 and 2020 are as follows (amounts in thousands): Three Months Ended Six Months Ended Rental revenue June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Fixed payments $ 124,432 $ 122,393 $ 250,204 $ 252,906 Variable payments 16,365 15,606 30,824 33,206 Total rental revenue $ 140,797 $ 137,999 $ 281,028 $ 286,112 As of June 30, 2021, 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 2039 (amounts in thousands): Remainder of 2021 $ 247,138 2022 497,384 2023 482,236 2024 447,203 2025 408,032 Thereafter 1,950,949 $ 4,032,942 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 $29.0 million and lease liabilities of $29.0 million in our consolidated balance sheets as of June 30, 2021. 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 June 30, 2021 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 June 30, 2021 was 48.9 years. As of June 30, 2021, 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 2021 $ 759 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted cash flows 72,093 Present value discount (43,095) Ground lease liabilities $ 28,998
Leases	Leases Lessor We lease various spaces to tenants over terms ranging from one Rental revenue includes fixed and variable payments. Fixed payments primarily relate to base rent and variable payments primarily relate to tenant expense reimbursements for certain property operating costs. The components of rental revenue for the three and six months ended June 30, 2021 and 2020 are as follows (amounts in thousands): Three Months Ended Six Months Ended Rental revenue June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Fixed payments $ 124,432 $ 122,393 $ 250,204 $ 252,906 Variable payments 16,365 15,606 30,824 33,206 Total rental revenue $ 140,797 $ 137,999 $ 281,028 $ 286,112 As of June 30, 2021, 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 2039 (amounts in thousands): Remainder of 2021 $ 247,138 2022 497,384 2023 482,236 2024 447,203 2025 408,032 Thereafter 1,950,949 $ 4,032,942 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 $29.0 million and lease liabilities of $29.0 million in our consolidated balance sheets as of June 30, 2021. 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 June 30, 2021 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 June 30, 2021 was 48.9 years. As of June 30, 2021, 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 2021 $ 759 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted cash flows 72,093 Present value discount (43,095) Ground lease liabilities $ 28,998

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings Except as described below, as of June 30, 2021, 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. This amount was recorded as an IPO litigation expense in the consolidated statement of operations for the year ended December 31, 2020. Respondents believe that such award in favor of the Claimants is entirely without merit and have sought to vacate that portion of the award. In addition, certain of the Claimants in the federal court action sought to pursue claims in that case against Respondents. Respondents believe that any such claims are meritless. The magistrate judge assigned to the action has issued a Report and Recommendation rejecting Claimants’ claims; the district judge will decide whether to adopt the Report and Recommendation. 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 June 30, 2021, we estimate that we will incur approximately $89.1 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 June 30, 2021, 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 June 30, 2021, 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 June 30, 2021, 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	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Capital	Capital As of June 30, 2021, there were 285,722,956 common stock and operating partnership units outstanding, of which 173,400,552, or 60.7%, were owned by ESRT and 112,322,404, or 39.3%, 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. LTIP units subject to market-based vesting 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, 2021. 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. There were no purchases of equity securities during the three months ended June 30, 2021. Private Perpetual Preferred Units As of June 30, 2021, 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 $9.5 million and $9.5 million for the three and six months ended June 30, 2021, respectively, and $30.6 million and $62.2 million for the three and six months ended June 30, 2020, respectively. Total distributions paid to preferred unitholders were $1.1 million and $2.1 million for the three and six months ended June 30, 2021, respectively, and $1.0 million and $2.1 million for the three and six months ended June 30, 2020, 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 June 30, 2021, 7.7 million shares of ESRT common stock remain available for future issuance. Annually, we make grants of LTIP units to our non-employee directors under the 2019 Plan. In 2021, each of our directors received 60% of their $200,000 annual base retainer in the form of equity vesting ratably over four years, and could elect to receive the remaining 40% of such base retainer (i) in cash at the face value of the award, (ii) in immediately vesting equity at the face value of the award, or (iii) in equity vesting ratably over three years at 120% of the face amount. Each director could elect to receive any equity portion of the base retainer in either (i) LTIP units or (ii) restricted shares of our Class A common stock. In accordance with each director's election, we granted a total of 126,713 LTIP units that are subject to time-based vesting with fair market values of $1.4 million and no restricted shares. The LTIP units vest ratably over three In COVID-19 disrupted markets which created unusual volatility in our share price 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. Thus, 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. Such volatility was not material in 2021, and no such adjustment was needed in 2021. 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 four three 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, 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 six months ended June 30, 2021 were valued at $19.8 million. The weighted average per unit or share fair value was $8.55 for grants issued in 2021. The per unit or share granted in 2021 was estimated on the respective dates of grant using the following assumptions: an expected life from 2.0 to 5.3 years, a dividend rate of 2.60%, a risk-free interest rate from 0.12% to 0.32%, and an expected price volatility from 36.0% to 53.0%. No other stock options, dividend equivalents, or stock appreciation rights were issued or outstanding in 2021. The following is a summary of ESRT restricted stock and LTIP unit activity for the six months ended June 30, 2021: Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2020 217,700 7,750,284 $ 6.94 Vested (70,649) (991,380) 11.54 Granted 120,313 2,194,877 8.55 Forfeited or unearned (14,540) (1,445,621) 5.56 Unvested balance at June 30, 2021 252,824 7,508,160 $ 7.04 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 $1.4 million for the three and six months ended June 30, 2021, respectively, and $0.3 million and $1.9 million for the three and six months ended June 30, 2020, respectively. Unrecognized compensation expense was $2.3 million at June 30, 2021, which will be recognized over a weighted average period of 2.5 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 $4.8 million and $8.6 million for the three and six months ended June 30, 2021, respectively, and $8.5 million and $12.8 million for the three and six months ended June 30, 2020, respectively. Unrecognized compensation expense was $34.7 million at June 30, 2021, which will be recognized over a weighted average period of 2.5 years. Earnings Per Unit Earnings per unit for the three and six months ended June 30, 2021 and 2020 is computed as follows (amounts in thousands, except per share amounts): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Numerator: Net income (loss) $ 4,411 $ (19,618) $ 1,220 $ (11,330) Private perpetual preferred unit distributions (1,051) (1,047) (2,101) (2,097) Earnings allocated to unvested units (113) (386) (113) (643) Net income (loss) attributable to common unitholders – basic and diluted $ 3,247 $ (21,051) $ (994) $ (14,070) Denominator: Weighted average units outstanding – basic 277,893 283,384 277,887 288,015 Effect of dilutive securities: Stock-based compensation plans 543 — — — Weighted average units outstanding –- diluted 278,436 283,384 277,887 288,015 Earnings (loss) per share: Basic $ 0.01 $ (0.07) $ 0.00 $ (0.05) Diluted $ 0.01 $ (0.07) $ 0.00 $ (0.05)

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2021
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 $0.3 million and $0.2 million for the three months ended June 30, 2021 and 2020, respectively, and $0.5 million and $0.5 million for the six months ended June 30, 2021 and 2020, 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 June 30, 2021 and 2020, respectively, and $0.1 million and $0.2 million for the six months ended June 30, 2021 and 2020, respectively. These fees are included within third-party management and other fees. Other We receive rent generally at the 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 June 30, 2021 and 2020, respectively, and $0.2 million and $0.2 million for the six months ended June 30, 2021 and 2020, respectively.

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2021
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 net income (loss) for each segment for the three and six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended June 30, 2021 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 140,797 $ — $ — $ 140,797 Intercompany rental revenue 6,029 — (6,029) — Observatory revenue — 8,359 — 8,359 Lease termination fees 3,339 — — 3,339 Third-party management and other fees 327 — — 327 Other revenue and fees 586 — — 586 Total revenues 151,078 8,359 (6,029) 153,408 Operating expenses: Property operating expenses 28,793 — — 28,793 Intercompany rent expense — 6,029 (6,029) — Ground rent expense 2,332 — — 2,332 General and administrative expenses 14,089 — — 14,089 Observatory expenses — 5,268 — 5,268 Real estate taxes 31,354 — — 31,354 Depreciation and amortization 45,066 22 — 45,088 Total operating expenses 121,634 11,319 (6,029) 126,924 Total operating income (loss) 29,444 (2,960) — 26,484 Other income (expense): Interest income 163 1 — 164 Interest expense (23,422) — — (23,422) Income (loss) before income taxes 6,185 (2,959) — 3,226 Income tax (expense) benefit (135) 1,320 — 1,185 Net income (loss) $ 6,050 $ (1,639) $ — $ 4,411 Segment assets $ 3,880,853 $ 242,619 $ — $ 4,123,472 Expenditures for segment assets $ 19,975 $ — $ — $ 19,975 Three Months Ended June 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 137,999 $ — $ — $ 137,999 Intercompany rental revenue 4,053 — (4,053) — Observatory revenue — 86 — 86 Lease termination fees 1,033 — — 1,033 Third-party management and other fees 301 — — 301 Other revenue and fees 1,611 — — 1,611 Total revenues 144,997 86 (4,053) 141,030 Operating expenses: Property operating expenses 29,750 — — 29,750 Intercompany rent expense — 4,053 (4,053) — Ground rent expense 2,332 — — 2,332 General and administrative expenses 18,149 — — 18,149 Observatory expenses — 4,002 — 4,002 Real estate taxes 29,579 — — 29,579 Impairment charges 4,101 — — 4,101 Depreciation and amortization 52,758 25 — 52,783 Total operating expenses 136,669 8,080 (4,053) 140,696 Total operating income (loss) 8,328 (7,994) — 334 Other income (expense): Interest income 1,441 85 — 1,526 Interest expense (23,928) — — (23,928) Loss before income taxes (14,159) (7,909) — (22,068) Income tax (expense) benefit (269) 2,719 — 2,450 Net loss $ (14,428) $ (5,190) $ — $ (19,618) Segment assets $ 4,305,105 $ 245,290 $ — $ 4,550,395 Expenditures for segment assets $ 20,100 $ 995 $ — $ 21,095 Six Months Ended June 30, 2021 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 281,028 $ — $ — $ 281,028 Intercompany rental revenue 10,961 — (10,961) — Observatory revenue — 10,962 — 10,962 Lease termination fees 4,628 — — 4,628 Third-party management and other fees 603 — — 603 Other revenue and fees 1,491 — — 1,491 Total revenues 298,711 10,962 (10,961) 298,712 Operating expenses: Property operating expenses 59,072 — — 59,072 Intercompany rent expense — 10,961 (10,961) — Ground rent expense 4,663 — — 4,663 General and administrative expenses 27,942 — — 27,942 Observatory expenses — 9,856 — 9,856 Real estate taxes 62,801 — — 62,801 Depreciation and amortization 89,485 60 — 89,545 Total operating expenses 243,963 20,877 (10,961) 253,879 Total operating income (loss) 54,748 (9,915) — 44,833 Other income (expense): Interest income 283 3 — 286 Interest expense (46,976) — — (46,976) Loss on early extinguishment of debt (214) — — (214) Income (loss) before income taxes 7,841 (9,912) — (2,071) Income tax (expense) benefit (418) 3,709 — 3,291 Net income (loss) $ 7,423 $ (6,203) $ — $ 1,220 Expenditures for segment assets $ 43,307 $ 4 $ — $ 43,311 Six Months Ended June 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 286,112 $ — $ — $ 286,112 Intercompany rental revenue 15,589 — (15,589) — Observatory revenue — 19,630 — 19,630 Lease termination fees 1,244 — — 1,244 Third-party management and other fees 647 — — 647 Other revenue and fees 3,621 — — 3,621 Total revenues 307,213 19,630 (15,589) 311,254 Operating expenses: Property operating expenses 71,218 — — 71,218 Intercompany rent expense — 15,589 (15,589) — Ground rent expense 4,663 — — 4,663 General and administrative expenses 34,100 — — 34,100 Observatory expenses — 12,156 — 12,156 Real estate taxes 58,833 — — 58,833 Impairment charges 4,101 — — 4,101 Depreciation and amortization 98,843 33 — 98,876 Total operating expenses 271,758 27,778 (15,589) 283,947 Total operating income (loss) 35,455 (8,148) — 27,307 Other income (expense): Interest income 2,078 85 — 2,163 Interest expense (43,546) — — (43,546) Loss on early extinguishment of debt (86) — — (86) Loss before income taxes (6,099) (8,063) — (14,162) Income tax (expense) benefit (496) 3,328 — 2,832 Net loss $ (6,595) $ (4,735) $ — $ (11,330) Expenditures for segment assets $ 46,672 $ 2,232 $ — $ 48,904 During the second quarter 2020, we wrote off $4.1 million of prior expenditures on a Combined Heat Power/Redundancy onsite power generation project in our real estate segment that is rendered economically unviable due to New York City's Local Law 97 and from its measurement of carbon from natural gas combustion generates fines. For the three and six months ended June 30, 2020, the $4.1 million write-off is shown as an impairment charge in the condensed consolidated statements of operations.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 29, 2021, GBG USA Inc., an indirect wholly-owned subsidiary of Global Brands Group Holding Limited, announced that its North America wholesale business and certain subsidiaries and affiliates (collectively, “GBG USA”) filed for bankruptcy under Chapter 11. At the time of the filing, GBG USA leased 353,325 square feet of office space at 1333 Broadway and the Empire State Building, or 3.5%, of our total portfolio rentable square feet , representing approximately 3.6% of total portfolio annualized rent. Of that total, all but 191,000 square feet, or 1.9% of our total portfolio rentable square feet, has been sublet to tenants, where both GBG USA and the subtenant are liable for the rent, and we have the right to require the subtenant to pay directly to us. The sublets are for GBG USA’s entire premises at 1333 Broadway and have been in effect for several years. We have current discussions to convert the subtenants to direct tenants.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
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, 2020 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 Coronavirus 19 ("COVID-19") pandemic.
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 June 30, 2021 and December 31, 2020.    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.
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 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.
Fair Valuation	The estimated fair values at June 30, 2021 and December 31, 2020 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 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 and unsecured revolving credit facility 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.

Deferred Costs, Acquired Leas_2

Deferred Costs, Acquired Lease Intangibles and Goodwill (Tables)	6 Months Ended
	Jun. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs, Net	Deferred costs, net, consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Leasing costs $ 205,599 $ 203,905 Acquired in-place lease value and deferred leasing costs 177,501 181,336 Acquired above-market leases 35,330 40,398 418,430 425,639 Less: accumulated amortization (226,021) (223,918) Total deferred costs, net, excluding net deferred financing costs $ 192,409 $ 201,721 June 30, 2021 December 31, 2020 Financing costs $ 42,689 $ 35,365 Less: accumulated amortization (20,338) (17,998) Total deferred financing costs, net $ 22,351 $ 17,367
Amortizing Acquired Intangible Assets and Liabilities	Amortizing acquired intangible assets and liabilities consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Acquired below-market ground leases $ 396,916 $ 396,916 Less: accumulated amortization (56,096) (52,181) Acquired below-market ground leases, net $ 340,820 $ 344,735 June 30, 2021 December 31, 2020 Acquired below-market leases $ (75,082) $ (78,451) Less: accumulated amortization 46,550 46,746 Acquired below-market leases, net $ (28,532) $ (31,705)

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Debt consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): Principal Balance As of June 30, 2021 June 30, 2021 December 31, 2020 Stated Effective (1) Maturity (2) Mortgage debt collateralized by: Fixed rate mortgage debt Metro Center $ 86,217 $ 87,382 3.59 % 3.66 % 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 % 4.73 % 7/1/2027 1010 Third Avenue and 77 West 55th Street 37,078 37,477 4.01 % 4.21 % 1/5/2028 250 West 57th Street 180,000 180,000 2.83 % 3.21 % 12/1/2030 10 Bank Street 31,563 32,025 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 784,858 786,884 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 100,000 100,000 3.61 % 4.89 % 3/17/2032 Series H 75,000 75,000 3.73 % 5.00 % 3/17/2035 Unsecured term loan facility (4) 215,000 215,000 LIBOR plus 1.20% 3.57 % 3/19/2025 Unsecured revolving credit facility (4) — — LIBOR plus 1.30% — 3/31/2025 Unsecured term loan facility (4) 175,000 175,000 LIBOR plus 1.50% 3.63 % 12/31/2026 Total principal 2,149,858 2,151,884 Deferred financing costs, net (14,025) (15,235) Total $ 2,135,833 $ 2,136,649 ______________ (1) The effective rate is the yield as of June 30, 2021 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 June 30, 2021, we were in compliance with all debt covenants.
Aggregate Required Principal Payments	Aggregate required principal payments at June 30, 2021 are as follows (amounts in thousands): Year Amortization Maturities Total 2021 $ 2,064 $ — $ 2,064 2022 5,628 — 5,628 2023 7,876 — 7,876 2024 7,958 77,675 85,633 2025 5,826 315,000 320,826 Thereafter 20,084 1,707,747 1,727,831 Total $ 49,436 $ 2,100,422 $ 2,149,858
Deferred Financing Costs, Net	Deferred costs, net, consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Leasing costs $ 205,599 $ 203,905 Acquired in-place lease value and deferred leasing costs 177,501 181,336 Acquired above-market leases 35,330 40,398 418,430 425,639 Less: accumulated amortization (226,021) (223,918) Total deferred costs, net, excluding net deferred financing costs $ 192,409 $ 201,721 June 30, 2021 December 31, 2020 Financing costs $ 42,689 $ 35,365 Less: accumulated amortization (20,338) (17,998) Total deferred financing costs, net $ 22,351 $ 17,367

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2021
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following as of June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 December 31, 2020 Accrued capital expenditures $ 52,891 $ 58,057 Accounts payable and accrued expenses 26,012 32,309 Interest rate swap agreements liability 6,176 8,849 Accrued interest payable 3,392 3,219 Due to affiliated companies 783 769 Total accounts payable and accrued expenses $ 89,254 $ 103,203

Financial Instruments and Fai_2

Financial Instruments and Fair Values (Tables)	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021 and December 31, 2020 (dollar amounts in thousands): June 30, 2021 December 31, 2020 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 $ — $ (6,176) $ — $ (8,849)
Effect of Derivative Financial Instruments Designated as Cash Flow Hedges on Accumulated Other Comprehensive Income (Loss)	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 six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended Six Months Ended Effects of Cash Flow Hedges June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Amount of gain (loss) recognized in other comprehensive income (loss) $ (95) $ (1,709) $ (36) $ (19,404) Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense (2,898) (2,317) (5,767) (3,113) 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 six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended Six Months Ended Effects of Cash Flow Hedges June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Total interest (expense) presented in the condensed consolidated statements of operations in which the effects of cash flow hedges are recorded $ (23,422) $ (23,928) $ (46,976) $ (43,546) Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense (2,898) (2,317) (5,767) (3,113)
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 June 30, 2021 and December 31, 2020 (amounts in thousands): June 30, 2021 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swap included in accounts payable and accrued expenses $ 6,176 $ 6,176 $ — $ 6,176 $ — Mortgage notes payable 774,612 791,438 — — 791,438 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,267 1,003,628 — — 1,003,628 Unsecured term loan facilities 387,954 390,000 — — 390,000 December 31, 2020 Estimated Fair Value Carrying Total Level 1 Level 2 Level 3 Interest rate swap included in accounts payable and accrued expenses $ 8,849 $ 8,849 $ — $ 8,849 $ — Mortgage notes payable 775,929 808,294 — — 808,294 Senior unsecured notes - Series A, B, C, D, E, F, G and H 973,159 1,039,857 — — 1,039,857 Unsecured term loan facilities 387,561 390,000 — — 390,000

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Schedule of Components of Rental Revenue	The components of rental revenue for the three and six months ended June 30, 2021 and 2020 are as follows (amounts in thousands): Three Months Ended Six Months Ended Rental revenue June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Fixed payments $ 124,432 $ 122,393 $ 250,204 $ 252,906 Variable payments 16,365 15,606 30,824 33,206 Total rental revenue $ 140,797 $ 137,999 $ 281,028 $ 286,112
Schedule of Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received	As of June 30, 2021, 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 2039 (amounts in thousands): Remainder of 2021 $ 247,138 2022 497,384 2023 482,236 2024 447,203 2025 408,032 Thereafter 1,950,949 $ 4,032,942
Schedule of Future Minimum Lease Payments	As of June 30, 2021, 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 2021 $ 759 2022 1,518 2023 1,518 2024 1,518 2025 1,518 Thereafter 65,262 Total undiscounted cash flows 72,093 Present value discount (43,095) Ground lease liabilities $ 28,998

Capital (Tables)

Capital (Tables)	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Summary of ERST Restricted Stock and LTIP Unit Activity	The following is a summary of ESRT restricted stock and LTIP unit activity for the six months ended June 30, 2021: Restricted Stock LTIP Units Weighted Average Grant Fair Value Unvested balance at December 31, 2020 217,700 7,750,284 $ 6.94 Vested (70,649) (991,380) 11.54 Granted 120,313 2,194,877 8.55 Forfeited or unearned (14,540) (1,445,621) 5.56 Unvested balance at June 30, 2021 252,824 7,508,160 $ 7.04
Earnings Per Unit	Earnings per unit for the three and six months ended June 30, 2021 and 2020 is computed as follows (amounts in thousands, except per share amounts): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Numerator: Net income (loss) $ 4,411 $ (19,618) $ 1,220 $ (11,330) Private perpetual preferred unit distributions (1,051) (1,047) (2,101) (2,097) Earnings allocated to unvested units (113) (386) (113) (643) Net income (loss) attributable to common unitholders – basic and diluted $ 3,247 $ (21,051) $ (994) $ (14,070) Denominator: Weighted average units outstanding – basic 277,893 283,384 277,887 288,015 Effect of dilutive securities: Stock-based compensation plans 543 — — — Weighted average units outstanding –- diluted 278,436 283,384 277,887 288,015 Earnings (loss) per share: Basic $ 0.01 $ (0.07) $ 0.00 $ (0.05) Diluted $ 0.01 $ (0.07) $ 0.00 $ (0.05)

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Components of Segment Net Income (Loss) for Each Segment	The following tables provide components of segment net income (loss) for each segment for the three and six months ended June 30, 2021 and 2020 (amounts in thousands): Three Months Ended June 30, 2021 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 140,797 $ — $ — $ 140,797 Intercompany rental revenue 6,029 — (6,029) — Observatory revenue — 8,359 — 8,359 Lease termination fees 3,339 — — 3,339 Third-party management and other fees 327 — — 327 Other revenue and fees 586 — — 586 Total revenues 151,078 8,359 (6,029) 153,408 Operating expenses: Property operating expenses 28,793 — — 28,793 Intercompany rent expense — 6,029 (6,029) — Ground rent expense 2,332 — — 2,332 General and administrative expenses 14,089 — — 14,089 Observatory expenses — 5,268 — 5,268 Real estate taxes 31,354 — — 31,354 Depreciation and amortization 45,066 22 — 45,088 Total operating expenses 121,634 11,319 (6,029) 126,924 Total operating income (loss) 29,444 (2,960) — 26,484 Other income (expense): Interest income 163 1 — 164 Interest expense (23,422) — — (23,422) Income (loss) before income taxes 6,185 (2,959) — 3,226 Income tax (expense) benefit (135) 1,320 — 1,185 Net income (loss) $ 6,050 $ (1,639) $ — $ 4,411 Segment assets $ 3,880,853 $ 242,619 $ — $ 4,123,472 Expenditures for segment assets $ 19,975 $ — $ — $ 19,975 Three Months Ended June 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 137,999 $ — $ — $ 137,999 Intercompany rental revenue 4,053 — (4,053) — Observatory revenue — 86 — 86 Lease termination fees 1,033 — — 1,033 Third-party management and other fees 301 — — 301 Other revenue and fees 1,611 — — 1,611 Total revenues 144,997 86 (4,053) 141,030 Operating expenses: Property operating expenses 29,750 — — 29,750 Intercompany rent expense — 4,053 (4,053) — Ground rent expense 2,332 — — 2,332 General and administrative expenses 18,149 — — 18,149 Observatory expenses — 4,002 — 4,002 Real estate taxes 29,579 — — 29,579 Impairment charges 4,101 — — 4,101 Depreciation and amortization 52,758 25 — 52,783 Total operating expenses 136,669 8,080 (4,053) 140,696 Total operating income (loss) 8,328 (7,994) — 334 Other income (expense): Interest income 1,441 85 — 1,526 Interest expense (23,928) — — (23,928) Loss before income taxes (14,159) (7,909) — (22,068) Income tax (expense) benefit (269) 2,719 — 2,450 Net loss $ (14,428) $ (5,190) $ — $ (19,618) Segment assets $ 4,305,105 $ 245,290 $ — $ 4,550,395 Expenditures for segment assets $ 20,100 $ 995 $ — $ 21,095 Six Months Ended June 30, 2021 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 281,028 $ — $ — $ 281,028 Intercompany rental revenue 10,961 — (10,961) — Observatory revenue — 10,962 — 10,962 Lease termination fees 4,628 — — 4,628 Third-party management and other fees 603 — — 603 Other revenue and fees 1,491 — — 1,491 Total revenues 298,711 10,962 (10,961) 298,712 Operating expenses: Property operating expenses 59,072 — — 59,072 Intercompany rent expense — 10,961 (10,961) — Ground rent expense 4,663 — — 4,663 General and administrative expenses 27,942 — — 27,942 Observatory expenses — 9,856 — 9,856 Real estate taxes 62,801 — — 62,801 Depreciation and amortization 89,485 60 — 89,545 Total operating expenses 243,963 20,877 (10,961) 253,879 Total operating income (loss) 54,748 (9,915) — 44,833 Other income (expense): Interest income 283 3 — 286 Interest expense (46,976) — — (46,976) Loss on early extinguishment of debt (214) — — (214) Income (loss) before income taxes 7,841 (9,912) — (2,071) Income tax (expense) benefit (418) 3,709 — 3,291 Net income (loss) $ 7,423 $ (6,203) $ — $ 1,220 Expenditures for segment assets $ 43,307 $ 4 $ — $ 43,311 Six Months Ended June 30, 2020 Real Estate Observatory Intersegment Elimination Total Revenues: Rental revenue $ 286,112 $ — $ — $ 286,112 Intercompany rental revenue 15,589 — (15,589) — Observatory revenue — 19,630 — 19,630 Lease termination fees 1,244 — — 1,244 Third-party management and other fees 647 — — 647 Other revenue and fees 3,621 — — 3,621 Total revenues 307,213 19,630 (15,589) 311,254 Operating expenses: Property operating expenses 71,218 — — 71,218 Intercompany rent expense — 15,589 (15,589) — Ground rent expense 4,663 — — 4,663 General and administrative expenses 34,100 — — 34,100 Observatory expenses — 12,156 — 12,156 Real estate taxes 58,833 — — 58,833 Impairment charges 4,101 — — 4,101 Depreciation and amortization 98,843 33 — 98,876 Total operating expenses 271,758 27,778 (15,589) 283,947 Total operating income (loss) 35,455 (8,148) — 27,307 Other income (expense): Interest income 2,078 85 — 2,163 Interest expense (43,546) — — (43,546) Loss on early extinguishment of debt (86) — — (86) Loss before income taxes (6,099) (8,063) — (14,162) Income tax (expense) benefit (496) 3,328 — 2,832 Net loss $ (6,595) $ (4,735) $ — $ (11,330) Expenditures for segment assets $ 46,672 $ 2,232 $ — $ 48,904

Description of Business and O_2

Description of Business and Organization (Details) ft² in Millions	6 Months Ended
	Jun. 30, 2021ft²office_and_propertyparcel
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Area of real estate property (in square feet)	10.1
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)	60.70%
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

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	Jun. 30, 2021
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	Jun. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Leasing costs	$ 205,599	$ 203,905
Total deferred costs, gross amount	418,430	425,639
Less: accumulated amortization	(226,021)	(223,918)
Total deferred costs, net, excluding net deferred financing costs	192,409	201,721
Acquired in-place lease value and deferred leasing costs
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	177,501	181,336
Acquired above-market leases
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	$ 35,330	$ 40,398

Deferred Costs, Acquired Leas_4

Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Deferred Costs [Line Items]
Amortization expense related to deferred leasing costs	$ 6,100	$ 6,400	$ 11,700	$ 12,300
Amortization expense related to acquired lease intangibles			3,300	4,400
Rental revenue related to amortization of below-market leases, net of above-market leases	700	$ 1,400	1,371	$ 2,274
Goodwill	491,479		491,479		$ 491,479
Observatory
Deferred Costs [Line Items]
Fair value in excess of carrying value (less than) (as a percent)		15.00%		15.00%
Observatory
Deferred Costs [Line Items]
Goodwill	227,500		227,500
Real estate
Deferred Costs [Line Items]
Goodwill	264,000		264,000
Lease agreements
Deferred Costs [Line Items]
Amortization expense related to acquired lease intangibles	1,600	$ 2,400
Unsecured revolving credit facility | Revolving credit facility
Deferred Costs [Line Items]
Net deferred financing costs	$ 8,300		$ 8,300		$ 2,100

Deferred Costs, Acquired Leas_5

Deferred Costs, Acquired Lease Intangibles and Goodwill - Amortizing Acquired Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Acquired below-market ground leases, net
Acquired below-market ground leases	$ 396,916	$ 396,916
Less: accumulated amortization	(56,096)	(52,181)
Acquired below-market ground leases, net	340,820	344,735
Acquired below-market leases, net
Acquired below-market leases	(75,082)	(78,451)
Less: accumulated amortization	46,550	46,746
Acquired below-market leases, net	$ (28,532)	$ (31,705)

Debt - Long-Term Debt (Details)

Debt - Long-Term Debt (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Outstanding borrowings	$ 0	$ 0
Total principal	2,149,858,000
Deferred financing costs, net	(22,351,000)	(17,367,000)
Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	784,858,000	786,884,000
Mortgages, senior notes, and unsecured term loan facilities, not including unsecured revolving credit facility
Debt Instrument [Line Items]
Total principal	2,149,858,000	2,151,884,000
Deferred financing costs, net	(14,025,000)	(15,235,000)
Total	2,135,833,000	2,136,649,000
Metro Center | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 86,217,000	87,382,000
Stated Rate (as a percentage)	3.59%
Effective Rate (as a percentage)	3.66%
10 Union Square | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 50,000,000	50,000,000
Stated Rate (as a percentage)	3.70%
Effective Rate (as a percentage)	3.97%
1542 Third Avenue | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 30,000,000	30,000,000
Stated Rate (as a percentage)	4.29%
Effective Rate (as a percentage)	4.53%
First Stamford Place | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 180,000,000	180,000,000
Stated Rate (as a percentage)	4.28%
Effective Rate (as a percentage)	4.73%
First Stamford Place - First Lien | Fixed rate mortgage debt
Debt Instrument [Line Items]
Stated Rate (as a percentage)	4.09%
Face amount	$ 164,000,000
First Stamford Place - Second Lien | Fixed rate mortgage debt
Debt Instrument [Line Items]
Stated Rate (as a percentage)	6.25%
Face amount	$ 16,000,000
1010 Third Avenue and 77 West 55th Street | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 37,078,000	37,477,000
Stated Rate (as a percentage)	4.01%
Effective Rate (as a percentage)	4.21%
250 West 57th Street | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 180,000,000	180,000,000
Stated Rate (as a percentage)	2.83%
Effective Rate (as a percentage)	3.21%
10 Bank Street | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 31,563,000	32,025,000
Stated Rate (as a percentage)	4.23%
Effective Rate (as a percentage)	4.36%
383 Main Avenue | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 30,000,000	30,000,000
Stated Rate (as a percentage)	4.44%
Effective Rate (as a percentage)	4.55%
1333 Broadway | Fixed rate mortgage debt
Debt Instrument [Line Items]
Fixed rate mortgage debt	$ 160,000,000	160,000,000
Stated Rate (as a percentage)	4.21%
Effective Rate (as a percentage)	4.29%
Senior unsecured notes, Series A | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 100,000,000	100,000,000
Stated Rate (as a percentage)	3.93%
Effective Rate (as a percentage)	3.96%
Senior unsecured notes, Series B | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 125,000,000	125,000,000
Stated Rate (as a percentage)	4.09%
Effective Rate (as a percentage)	4.12%
Senior unsecured notes, Series C | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 125,000,000	125,000,000
Stated Rate (as a percentage)	4.18%
Effective Rate (as a percentage)	4.21%
Senior unsecured notes, Series D | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 115,000,000	115,000,000
Stated Rate (as a percentage)	4.08%
Effective Rate (as a percentage)	4.11%
Senior unsecured notes, Series E | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 160,000,000	160,000,000
Stated Rate (as a percentage)	4.26%
Effective Rate (as a percentage)	4.27%
Senior unsecured notes, Series F | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 175,000,000	175,000,000
Stated Rate (as a percentage)	4.44%
Effective Rate (as a percentage)	4.45%
Senior unsecured notes, Series G | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 100,000,000	100,000,000
Stated Rate (as a percentage)	3.61%
Effective Rate (as a percentage)	4.89%
Senior unsecured notes, Series H | Senior unsecured notes
Debt Instrument [Line Items]
Total	$ 75,000,000	75,000,000
Stated Rate (as a percentage)	3.73%
Effective Rate (as a percentage)	5.00%
Unsecured term loan facilities | Revolving credit facility
Debt Instrument [Line Items]
Outstanding borrowings	$ 215,000,000	215,000,000
Effective Rate (as a percentage)	3.57%
Unsecured term loan facilities | Revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percentage)	1.20%
Unsecured revolving credit facility | Revolving credit facility
Debt Instrument [Line Items]
Outstanding borrowings	$ 0	0
Effective Rate (as a percentage)	0.00%
Unsecured revolving credit facility | Revolving credit facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percentage)	1.30%
Unsecured term loan facility | Revolving credit facility
Debt Instrument [Line Items]
Outstanding borrowings	$ 175,000,000	$ 175,000,000
Effective Rate (as a percentage)	3.63%
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	Jun. 30, 2021USD ($)
Amortization
2021	$ 2,064
2022	5,628
2023	7,876
2024	7,958
2025	5,826
Thereafter	20,084
Total	49,436
Maturities
2021	0
2022	0
2023	0
2024	77,675
2025	315,000
Thereafter	1,707,747
Total	2,100,422
Total
2021	2,064
2022	5,628
2023	7,876
2024	85,633
2025	320,826
Thereafter	1,727,831
Total	$ 2,149,858

Debt - Deferred Financing Costs

Debt - Deferred Financing Costs, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Debt Disclosure [Abstract]
Financing costs	$ 42,689		$ 42,689		$ 35,365
Less: accumulated amortization	(20,338)		(20,338)		(17,998)
Total deferred financing costs, net	22,351		22,351		$ 17,367
Amortization expense related to deferred financing costs	$ 1,100	$ 1,000	$ 2,300	$ 2,000

Debt - Unsecured Revolving Cred

Debt - Unsecured Revolving Credit and Term Loan Facilities (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 0	$ 0
Revolving credit facility | Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	1,065,000,000
Revolving credit facility | Unsecured revolving credit facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	850,000,000
Outstanding borrowings	0	0
Revolving credit facility | Unsecured term loan facilities
Line of Credit Facility [Line Items]
Maximum borrowing capacity	215,000,000
Outstanding borrowings	215,000,000	215,000,000
Revolving credit facility | Unsecured term loan facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	175,000,000
Outstanding borrowings	$ 175,000,000	$ 175,000,000

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued capital expenditures	$ 52,891	$ 58,057
Accounts payable and accrued expenses	26,012	32,309
Interest rate swap agreements liability	6,176	8,849
Accrued interest payable	3,392	3,219
Due to affiliated companies	783	769
Total accounts payable and accrued expenses	$ 89,254	$ 103,203

Financial Instruments and Fai_3

Financial Instruments and Fair Values - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	$ 6,176,000		$ 6,176,000		$ 8,849,000
Net unrealized gain (loss)			5,700,000	$ (16,300,000)
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)
Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	6,200,000		6,200,000
Interest rate swap | Designated as hedging instrument | Cash flow hedging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate notional value	265,000,000		265,000,000		265,000,000
Net unrealized gain (loss)	2,800,000	$ 600,000
Interest rate swap | Designated as hedging instrument | Cash flow hedging | Accounts payable and accrued expenses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements liability	$ 6,200,000		$ 6,200,000		$ 8,800,000

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) - LIBOR - Cash flow hedging - Designated as hedging instrument - Interest Rate Swap, One Month LIBOR, 2.1485% - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Notional Amount	$ 265,000,000
Pay Rate	2.1485%
Asset	$ 0	$ 0
Liability	$ (6,176,000)	$ (8,849,000)

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (95)	$ (1,709)	$ (36)	$ (19,404)
Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense	(2,898)	(2,317)	(5,767)	(3,113)
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	(95)	(1,709)	(36)	(19,404)
Amount of gain (loss) reclassified from accumulated other comprehensive (loss) into interest expense	(2,898)	(2,317)	(5,767)	(3,113)
Interest rate swap | Reclassification out of accumulated other comprehensive income | Accumulated other comprehensive income (loss)
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (2,898)	$ (2,317)	$ (5,767)	$ (3,113)

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	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	$ 6,176	$ 8,849
Interest rate swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	6,200
Carrying Value | Mortgage notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	774,612	775,929
Carrying Value | Senior notes | Senior unsecured notes - Series A, B, C, D, E, F, G and H
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	973,267	973,159
Carrying Value | Revolving credit facility | Unsecured term loan facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	387,954	387,561
Carrying Value | Interest rate swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	6,176	8,849
Estimated Fair Value | Mortgage notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	791,438	808,294
Estimated Fair Value | Senior notes | Senior unsecured notes - Series A, B, C, D, E, F, G and H
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,003,628	1,039,857
Estimated Fair Value | Revolving credit facility | Unsecured term loan facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	390,000	390,000
Estimated Fair Value | Level 1 | Mortgage notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 1 | Senior notes | Senior unsecured notes - Series A, B, C, D, E, F, G and H
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 1 | Revolving credit facility | Unsecured term loan facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 2 | Mortgage notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 2 | Senior notes | Senior unsecured notes - Series A, B, C, D, E, F, G and H
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 2 | Revolving credit facility | Unsecured term loan facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Estimated Fair Value | Level 3 | Mortgage notes payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	791,438	808,294
Estimated Fair Value | Level 3 | Senior notes | Senior unsecured notes - Series A, B, C, D, E, F, G and H
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,003,628	1,039,857
Estimated Fair Value | Level 3 | Revolving credit facility | Unsecured term loan facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	390,000	390,000
Estimated Fair Value | Interest rate swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	6,176	8,849
Estimated Fair Value | Interest rate swap | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	0	0
Estimated Fair Value | Interest rate swap | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	6,176	8,849
Estimated Fair Value | Interest rate swap | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap included in accounts payable and accrued expenses	$ 0	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	Jun. 30, 2021USD ($)property	Dec. 31, 2020USD ($)
Operating Leases [Line Items]
Number of properties subject to ground leases | property	3
Right-of-use assets	$ 28,998	$ 29,104
Lease liabilities	$ 28,998	$ 29,104
Weighted average discount rate	4.50%
Weighted average remaining lease term (in years)	48 years 10 months 24 days
Minimum
Operating Leases [Line Items]
Term of lease (in years)	1 year
Maximum
Operating Leases [Line Items]
Term of lease (in years)	21 years

Leases - Components of Rental R

Leases - Components of Rental Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Fixed payments	$ 124,432	$ 122,393	$ 250,204	$ 252,906
Variable payments	16,365	15,606	30,824	33,206
Total rental revenue	$ 140,797	$ 137,999	$ 281,028	$ 286,112

Leases - Future Contractual Min

Leases - Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received (Details) $ in Thousands	Jun. 30, 2021USD ($)
Leases [Abstract]
Remainder of 2021	$ 247,138
2022	497,384
2023	482,236
2024	447,203
2025	408,032
Thereafter	1,950,949
Total future minimum lease payments on non-cancellable operating leases to be received	$ 4,032,942

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments on Ground Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Remainder of 2021	$ 759
2022	1,518
2023	1,518
2024	1,518
2025	1,518
Thereafter	65,262
Total undiscounted cash flows	72,093
Present value discount	(43,095)
Ground lease liabilities	$ 28,998	$ 29,104

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 plaintiffs opting out of settlement (participant) | 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	Jun. 30, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Estimated capital expenditures to be incurred	$ 89.1

Capital - Additional Informatio

Capital - Additional Information and Private Perpetual Preferred Units (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	May 16, 2019
Shares and Units [Abstract]
OP units outstanding (in shares)	285,722,956		285,722,956
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%
Stock repurchase authorized amount	$ 500,000,000		$ 500,000,000
Purchases of equity securities (shares)	0
Dividends declared (in USD per share)	$ 0.035	$ 0.105	$ 0.035	$ 0.210
2019 Plan
Shares and Units [Abstract]
Number of shares authorized under the plan (in shares)	11,000,000		11,000,000			11,000,000
Private perpetual preferred units, series 2019
Shares and Units [Abstract]
Private perpetual preferred units, issued (in shares)	4,664,038		4,664,038		4,664,000
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)	1,560,000		1,560,000		1,560,000
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
Empire state realty trust
Shares and Units [Abstract]
OP units owned by the Company (in shares)	173,400,552		173,400,552
Empire state realty trust | Empire state realty OP
Shares and Units [Abstract]
OP units owned by the Company (as a percent)			60.70%
Other partners, certain directors, officers and other members of executive management
Shares and Units [Abstract]
OP units not owned by the Company (in shares)	112,322,404		112,322,404
Other partners, certain directors, officers and other members of executive management | Empire state realty OP
Shares and Units [Abstract]
OP units not owned by the Company (as a percent)			39.30%

Capital - Distributions (Detail

Capital - Distributions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Equity [Abstract]
Distributions paid to OP unitholders	$ 9.5	$ 30.6	$ 9.5	$ 62.2
Distributions paid to preferred unitholders	$ 1.1	$ 1	$ 2.1	$ 2.1

Capital - Incentive and Share-b

Capital - Incentive and Share-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended			6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	May 16, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Retirement age (in years)				65 years	60 years	65 years
Expected volatility rate look-back period (in years)						6 years
Weighted-average per unit or share fair value (in USD per share)						$ 8.55
Period of service, upon completion of which, grantee's LTIP unit and restricted stock awards will immediately vest (in years)						10 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Age of grantee at which LTIP unit and restricted stock awards immediately vest (in years)						60 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Age of grantee at which LTIP unit and restricted stock awards immediately vest (in years)						65 years
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			$ 400		$ 300	$ 1,400	$ 1,900
Unrecognized compensation expense	$ 2,300		2,300			$ 2,300
Unrecognized compensation expense, period for recognition (in years)						2 years 6 months
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			4,800		$ 8,500	$ 8,600	$ 12,800
Unrecognized compensation expense	$ 34,700		$ 34,700			$ 34,700
Unrecognized compensation expense, period for recognition (in years)						2 years 6 months
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						$ 19,800
Weighted-average per unit or share fair value (in USD per share)						$ 8.55
Dividend rate (as a percent)						2.60%
Risk free interest rate, minimum (as a percent)						0.12%
Risk free interest rate, maximum (as a percent)						0.32%
Expected price volatility, minimum (as a percent)						36.00%
Expected price volatility, maximum (as a percent)						53.00%
Long-term incentive plan units and restricted stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)						2 years
Long-term incentive plan units and restricted stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)						5 years 3 months 18 days
Time based long-term 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-term incentive plan unit | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)						3 years
Time based long-term incentive plan unit | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)						5 years
Time based long-term incentive plan unit | Median
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)						4 years
Market based long-Term incentive plan unit | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)						3 years
Market based long-Term incentive plan unit | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)						4 years
Market based long-Term incentive plan unit | Executive officer | 2019 Plan Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction of grants (in shares)		666,933
Fair value of reduction of share-based awards granted in period		$ 2,800
Market based long-Term incentive plan unit | Certain other employees | 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		$ 500
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		11,000,000
Number of shares that remain available for future issuance (in shares)	7,700,000		7,700,000			7,700,000
2019 Plan | Time based long-term incentive plan unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	8,324
Fair value of share-based awards granted in period	$ 100
2019 Plan | Time based long-term incentive plan unit | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual base retainer	$ 200		$ 200			$ 200
Vesting percentage of award face amount	120.00%		120.00%			120.00%
Shares granted (in shares)	126,713
Fair value of share-based awards granted in period	$ 1,400
2019 Plan | Time based long-term incentive plan unit | Director | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
2019 Plan | Time based long-term incentive plan unit | Director | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	4 years
2019 Plan | Time based long-term incentive plan unit | Director | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	60.00%
Award vesting period (in years)	4 years
2019 Plan | Time based long-term incentive plan unit | Director | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	40.00%
Award vesting period (in years)	3 years

Capital - Summary of ESRT Restr

Capital - Summary of ESRT Restricted Stock and LTIP Unit Activity (Details)	6 Months Ended
	Jun. 30, 2021$ / sharesshares
Weighted Average Grant Fair Value
Beginning balance, Unvested (in USD per share) | $ / shares	$ 6.94
Vested (in USD per share) | $ / shares	11.54
Granted (in USD per share) | $ / shares	8.55
Forfeited or unearned (in USD per share) | $ / shares	5.56
Ending balance, Unvested (in USD per share) | $ / shares	$ 7.04
Restricted Stock
Restricted Stock and LTIP Units
Beginning balance, Unvested (in shares)	217,700
Vested (in shares)	(70,649)
Granted (in shares)	120,313
Forfeited or unearned (in shares)	(14,540)
Ending balance, Unvested (in shares)	252,824
LTIP Units
Restricted Stock and LTIP Units
Beginning balance, Unvested (in shares)	7,750,284
Vested (in shares)	(991,380)
Granted (in shares)	2,194,877
Forfeited or unearned (in shares)	(1,445,621)
Ending balance, Unvested (in shares)	7,508,160

Capital - Earnings Per Unit (De

Capital - Earnings Per Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income (loss)	$ 4,411	$ (19,618)	$ 1,220	$ (11,330)
Private perpetual preferred unit distributions	(1,051)	(1,047)	(2,101)	(2,097)
Earnings allocated to unvested units	(113)	(386)	(113)	(643)
Net income (loss) attributable to common unitholders – basic and diluted	$ 3,247	$ (21,051)	$ (994)	$ (14,070)
Denominator:
Weighted average units outstanding - basic (in shares)	277,893,000	283,384,000	277,887,000	288,015,000
Effect of dilutive securities:
Stock-based compensation plans (in share)	543,000	0	0	0
Weighted average units outstanding - diluted (in shares)	278,436,000	283,384,000	277,887,000	288,015,000
Earnings (loss) per share:
Basic (in USD per share)	$ 0.01	$ (0.07)	$ 0	$ (0.05)
Diluted (in USD per share)	$ 0.01	$ (0.07)	$ 0	$ (0.05)
Antidilutive securities (in shares)	1,051,016	109,649	954,584	254,772

Related Party Transactions (Det

Related Party Transactions (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)ft²property	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)ft²property	Jun. 30, 2020USD ($)
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	$ 0.3	$ 0.2	$ 0.5	$ 0.5
Affliliated entity | Property management fee revenue
Related Party Transaction [Line Items]
Revenue from related parties	0.1	0.1	0.1	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		6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)segment	Jun. 30, 2020USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Impairment charges	$ 0	$ 4,101	$ 0	$ 4,101
Real Estate
Segment Reporting Information [Line Items]
Impairment charges		$ 4,100		$ 4,100

Segment Reporting - Components

Segment Reporting - Components of Segment Net Income (Loss) for Each Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenues:
Rental revenue	$ 140,797	$ 137,999	$ 281,028	$ 286,112
Intercompany rental revenue	0	0	0	0
Observatory revenue	8,359	86	10,962	19,630
Lease termination fees	3,339	1,033	4,628	1,244
Third-party management and other fees	327	301	603	647
Other revenue and fees	586	1,611	1,491	3,621
Total revenues	153,408	141,030	298,712	311,254
Operating expenses:
Property operating expenses	28,793	29,750	59,072	71,218
Intercompany rent expense	0	0	0	0
Ground rent expense	2,332	2,332	4,663	4,663
General and administrative expenses	14,089	18,149	27,942	34,100
Observatory expenses	5,268	4,002	9,856	12,156
Real estate taxes	31,354	29,579	62,801	58,833
Impairment charges	0	4,101	0	4,101
Depreciation and amortization	45,088	52,783	89,545	98,876
Total operating expenses	126,924	140,696	253,879	283,947
Total operating income (loss)	26,484	334	44,833	27,307
Other income (expense):
Interest income	164	1,526	286	2,163
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Loss on early extinguishment of debt	0	0	(214)	(86)
Income (loss) before income taxes	3,226	(22,068)	(2,071)	(14,162)
Income tax (expense) benefit	1,185	2,450	3,291	2,832
Net income (loss)	4,411	(19,618)	1,220	(11,330)
Segment assets	4,123,472	4,550,395	4,123,472	4,550,395	$ 4,150,695
Expenditures for segment assets	19,975	21,095	43,311	48,904
Intersegment Elimination
Revenues:
Intercompany rental revenue	(6,029)	(4,053)	(10,961)	(15,589)
Total revenues	(6,029)	(4,053)	(10,961)	(15,589)
Operating expenses:
Intercompany rent expense	(6,029)	(4,053)	(10,961)	(15,589)
General and administrative expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Total operating expenses	(6,029)	(4,053)	(10,961)	(15,589)
Total operating income (loss)	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
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
Real Estate
Operating expenses:
Impairment charges		4,100		4,100
Real Estate | Operating segments
Revenues:
Rental revenue	140,797	137,999	281,028	286,112
Intercompany rental revenue	6,029	4,053	10,961	15,589
Lease termination fees	3,339	1,033	4,628	1,244
Third-party management and other fees	327	301	603	647
Other revenue and fees	586	1,611	1,491	3,621
Total revenues	151,078	144,997	298,711	307,213
Operating expenses:
Property operating expenses	28,793	29,750	59,072	71,218
Ground rent expense	2,332	2,332	4,663	4,663
General and administrative expenses	14,089	18,149	27,942	34,100
Real estate taxes	31,354	29,579	62,801	58,833
Impairment charges				4,101
Depreciation and amortization	45,066	52,758	89,485	98,843
Total operating expenses	121,634	136,669	243,963	271,758
Total operating income (loss)	29,444	8,328	54,748	35,455
Other income (expense):
Interest income	163	1,441	283	2,078
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Loss on early extinguishment of debt			(214)	(86)
Income (loss) before income taxes	6,185	(14,159)	7,841	(6,099)
Income tax (expense) benefit	(135)	(269)	(418)	(496)
Net income (loss)	6,050	(14,428)	7,423	(6,595)
Segment assets	3,880,853	4,305,105	3,880,853	4,305,105
Expenditures for segment assets	19,975	20,100	43,307	46,672
Observatory | Operating segments
Revenues:
Intercompany rental revenue	0	0	0	0
Observatory revenue	8,359	86	10,962	19,630
Total revenues	8,359	86	10,962	19,630
Operating expenses:
Intercompany rent expense	6,029	4,053	10,961	15,589
General and administrative expenses	0	0	0	0
Observatory expenses	5,268	4,002	9,856	12,156
Depreciation and amortization	22	25	60	33
Total operating expenses	11,319	8,080	20,877	27,778
Total operating income (loss)	(2,960)	(7,994)	(9,915)	(8,148)
Other income (expense):
Interest income	1	85	3	85
Interest expense	0	0	0	0
Loss on early extinguishment of debt			0
Income (loss) before income taxes	(2,959)	(7,909)	(9,912)	(8,063)
Income tax (expense) benefit	1,320	2,719	3,709	3,328
Net income (loss)	(1,639)	(5,190)	(6,203)	(4,735)
Segment assets	242,619	245,290	242,619	245,290
Expenditures for segment assets	$ 0	$ 995	$ 4	$ 2,232

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	Jul. 29, 2021USD ($)ft²	Sep. 30, 2021USD ($)	Jun. 30, 2021ft²
Subsequent Event [Line Items]
Area of real estate property (in square feet)			10,100,000
Forecast
Subsequent Event [Line Items]
Straight line rent receivables written-off | $		$ 1.6
Subsequent Event
Subsequent Event [Line Items]
Letter of credit converted to cash | $	$ 17
Subsequent Event | Subsidiaries | GBG USA Inc.
Subsequent Event [Line Items]
Area of real estate property (in square feet)	353,325
Proportion of rentable square feet in total portfolio (as a percent)	3.50%
Proportion of annualized rent in total portfolio (as a percent)	3.60%
Area of real estate property that was not sublet to tenants (in square feet)	191,000
Proportion of rentable square feet in total portfolio that was not sublet to tenants (as a percent)	1.90%