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

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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