Segment Reporting [Abstract] Number of reportable segments Number of Reportable Segments Fair Value Disclosures [Abstract] Summary of the Terms of Agreements and the Fair Value of Derivative Financial Instruments Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Effect of Derivative Financial Instruments Designated as Cash Flow Hedges Derivative Instruments, Gain (Loss) [Table Text Block] Summary of the Carrying and Estimated Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated other comprehensive income (loss) Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap Interest Rate Swap [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Amount of gain (loss) recognized in other comprehensive income (loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Interest expense Interest Expense Statement of Partners' Capital [Abstract] Statement [Table] Statement [Table] Private Perpetual Preferred Units Private Perpetual Preferred Units [Member] Private Perpetual Preferred Units [Member] Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] General Partner General Partner [Member] Limited Partners Limited Partner [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series PR Operating Partnership Units Series PR Common Units [Member] Series PR Common Units [Member] Series ES Operating Partnership Units Limited Partners Series ES Operating Partnership Units [Member] Series ES Operating Partnership Units [Member] Series 60 Operating Partnership Units Limited Partners Series 60 Operating Partnership Units [Member] Series 60 Operating Partnership Units [Member] Series 250 Operating Partnership Units Limited Partners Series 250 Operating Partnership Units [Member] Series 250 Operating Partnership Units [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Partners' Capital [Roll Forward] Increase (Decrease) in Partners' Capital [Roll Forward] Beginning balance (in units) Partners' Capital Account, Units Beginning balance Partners' Capital Issuance of private perpetual preferred in exchange for common units (in units) Stock Issued During Period, Shares, Conversion Of Common Units To Private Perpetual Preferred Units Stock Issued During Period, Shares, Conversion Of Common Units To Private Perpetual Preferred Units Issuance of private perpetual preferred in exchange for common units Stock Issued During Period, Value, Conversion Of Common Units To Private Perpetual Preferred Units Stock Issued During Period, Value, Conversion of Private Perpetual Preferred Units Conversion of operating partnership units to ESRT Partner's Capital (in units) Stock Issued During Period, Shares, Conversion of Units Conversion of operating partnership units to ESRT Partner's Capital Stock Issued During Period, Value, Conversion of Units Repurchases of common units (in units) Stock Repurchased During Period, Shares Repurchases of common units Stock Repurchased During Period, Value Equity compensation (in units) Partners' Capital Account, Unit-based Payment Arrangement, Number of Units Equity compensation Partners' Capital Account, Unit-based Payment Arrangement, Amount Distributions Partners' Capital Account, Distributions Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Ending balance (in units) Ending balance Equity [Abstract] Schedule of Equity Securities Repurchased Accelerated Share Repurchases [Table Text Block] Summary of ERST Restricted Stock and LTIP Unit Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Earnings Per Unit Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Restricted Stock Restricted Stock [Member] LTIP Units Long-Term Incentive Plan Unit [Member] Long-Term Incentive Plan Unit [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Restricted Stock and LTIP Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning balance, Unvested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Forfeited or unearned (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Ending balance, Unvested (in shares) Weighted Average Grant Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Beginning balance, Unvested (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Vested (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Granted (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Forfeited or unearned (in USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Ending balance, Unvested (in USD per share) Distributions paid to OP unitholders Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Distributions paid to preferred unitholders Payments of Private Perpetual Preferred Units Distributions Payments of Private Perpetual Preferred Units Distributions Leases [Abstract] Schedule of Components of Rental Revenue Operating Lease, Lease Income [Table Text Block] Schedule of Future Contractual Minimum Lease Payments On Non-Cancellable Operating Leases To Be Received Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Schedule of Future Minimum Lease Payments Lessee, Operating Lease, Liability, Maturity [Table Text Block] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Deferred Costs, Net Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Amortizing Acquired Intangible Assets and Liabilities Schedule of Amortizing Acquired Intangible Assets and Liabilities [Table Text Block] Schedule of Amortizing Acquired Intangible Assets and Liabilities [Table Text Block] Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Table] Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Table] Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Real Estate Real Estate, Segment [Member] Real Estate, Segment [Member] Observatory Observatory, Segment [Member] Observatory, Segment [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Intersegment Elimination Intersegment Eliminations [Member] Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Line Items] Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Line Items] [Line Items] for Reconciliation of Revenue and Profit or Loss from Segments to Consolidated [Table] Revenues: Revenues [Abstract] Rental revenue Operating Lease, Lease Income Intercompany rental revenue Intercompany Rental Revenue Intercompany Rental Revenue Tenant expense reimbursement Tenant Reimbursements1 Tenant Expense Reimbursement Observatory revenue Observatory Revenue Observatory Revenue Lease termination fees Lease Termination Fees Revenue Lease Termination Fees Revenue Third-party management and other fees Property Management Fee Revenue Other revenue and fees Other Operating Income Total revenues Revenues Operating expenses: Operating Expenses [Abstract] Property operating expenses Operating Costs and Expenses Intercompany rent expense Intercompany Rent Expense Intercompany Rent Expense Ground rent expense Ground Rent Expense Ground Rent Expense General and administrative expenses Selling, General and Administrative Expense Observatory expenses Observatory Expense Observatory Expense Real estate taxes Real Estate Tax Expense Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Total operating expenses Operating Expenses Total operating income Operating Income (Loss) Other income (expense): Other Nonoperating Income (Expense) [Abstract] Interest income Investment Income, Net Interest expense Loss on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax (expense) benefit Income Tax Expense (Benefit) Net income Segment assets Assets Expenditures for segment assets Payments to Acquire Productive Assets Stock repurchase authorized amount Stock Repurchase Program, Authorized Amount Class of Treasury Stock [Table] Class of Treasury Stock [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Total Number of Shares Purchased (in shares) Average Price Paid per Share (in usd per share) Treasury Stock Acquired, Average Cost Per Share Maximum Approximate Dollar Value Available for Future Purchase Stock Repurchase Program, Remaining Authorized Repurchase Amount Deferred Costs [Table] Deferred Costs [Table] Deferred Costs [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving credit facility Revolving Credit Facility [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Unsecured revolving credit facility Unsecured Revolving Credit Facility [Member] Unsecured Revolving Credit Facility [Member] Real estate Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Lease agreements Lease Agreements [Member] Deferred Costs [Line Items] Deferred Costs [Line Items] [Line Items] for Deferred Costs [Table] Net deferred financing costs Debt Issuance Costs, Line of Credit Arrangements, Net Amortization expense related to deferred leasing costs Amortization Of Deferred Costs, Leasing Amortization Of Deferred Costs, Leasing Amortization expense related to deferred leasing costs Amortization of Deferred Leasing Fees Amortization expense related to acquired lease intangibles Amortization of Intangible Assets Rental revenue related to amortization of below-market leases, net of above-market leases Amortization of above and below Market Leases Goodwill Goodwill Leases Lessee, Operating Leases [Text Block] Leases Lessor, Operating Leases [Text Block] Fixed payments Operating Lease, Lease Income, Lease Payments Variable payments Operating Lease, Variable Lease Income Total rental revenue Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior notes Senior Notes [Member] Series G and Series H Senior Unsecured Notes Series G And Series H Senior Unsecured Notes [Member] Series G And Series H Senior Unsecured Notes [Member] Senior unsecured notes, Series G Series G Senior Notes due 2032 [Member] Series G Senior Notes due 2032 [Member] Senior unsecured notes, Series H Series H Senior Notes due 2035 [Member] Series H Senior Notes due 2035 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Face amount Debt Instrument, Face Amount Stated rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Issue price, as a percent of aggregate principal amount Debt Instrument, Issue Price, Percentage Of Aggregate Principal Amount Debt Instrument, Issue Price, Percentage Of Aggregate Principal Amount Long-Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Aggregate Required Principal Payments Schedule of Maturities of Long-term Debt [Table Text Block] Accounting Policies [Abstract] Basis of Quarterly Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Consolidation Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Principles of Consolidation for Variable Interest Entities Consolidation, Variable Interest Entity, Policy [Policy Text Block] Accounting Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue [Policy Text Block] Recently Issued or Adopted Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Acquired in-place lease value and deferred leasing costs Acquired In Place Lease Value And Deferred Leasing Costs [Member] Acquired In Place Lease Value And Deferred Leasing Costs [Member] Acquired above-market leases Above Market Leases [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Leasing costs Deferred Costs, Leasing, Gross Acquired finite-lived intangible assets Finite-Lived Intangible Assets, Gross Deferred costs, gross Deferred Costs, Gross Deferred Costs, Gross Less: accumulated amortization Accumulated Amortization, Deferred Costs Accumulated Amortization, Deferred Costs Total deferred costs, net, excluding net deferred financing costs Deferred Costs, Noncurrent Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2019 Plan 2019 Plan [Member] 2019 Plan [Member] Title of Individual [Axis] Title of Individual [Axis] Title of Individual [Domain] Title of Individual [Domain] Executive Officer Executive Officer [Member] Director Director [Member] Long-Term Incentive Plan Units and Restricted Stock Long-Term Incentive Plan Units and Restricted Stock [Member] Long-Term Incentive Plan Units and Restricted Stock [Member] Time Based Long-Tern Incentive Plan Unit Time Based Long-Tern Incentive Plan Unit [Member] Time Based Long-Tern Incentive Plan Unit [Member] Market Based Long-Term Incentive Plan Unit Market Based Long-Term Incentive Plan Unit [Member] Market Based Long-Term Incentive Plan Unit [Member] Time Restricted Shares Time Restricted Shares [Member] Time Restricted Shares [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] 2019 Plan Units 2019 Plan Units [Member] 2019 Plan Units [Member] 2019 Plan Units, Connected With Bonus Program 2019 Plan Units, Connected With Bonus Program [Member] 2019 Plan Units, Connected With Bonus Program [Member] 2013 Plan Units 2013 Plan Units [Member] 2013 Plan Units [Member] 2013 Plan Units, connected with bonus program 2013 Plan Units, Connected With Bonus Program [Member] 2013 Plan Units, Connected With Bonus Program [Member] Vesting immediately Share-based Payment Arrangement, Tranche One [Member] Vest ratably over three years Share-based Payment Arrangement, Tranche Two [Member] Vest in two equal annual installments Share-based Payment Arrangement, Tranche Three [Member] Awards that meet age and service requirements for vesting Awards that Meet Age and Service Requirements for Vesting [Member] Awards that Meet Age and Service Requirements for Vesting [Member] Awards that do not meet age and service requirements for vesting Awards that Do Not Meet Age and Service Requirements for Vesting [Member] Awards that Do Not Meet Age and Service Requirements for Vesting [Member] Number of shares authorized under the plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Number of shares that remain available for future issuance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Shares granted (in shares) Fair value of share-based awards granted in period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted in Period, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted in Period, Fair Value Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of vesting installments Number of Vesting Installments Number of Vesting Installments Vesting percentage of award face amount Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Percentage Of Award Face Amount Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Percentage Of Award Face Amount Threshold of continuous service for retirement eligibility (in years) Share-based Compensation Arrangement by Share-based Payment Award, Threshold Service Years For Retirement Eligibility Share-based Compensation Arrangement by Share-based Payment Award, Threshold Service Years For Retirement Eligibility Expected volatility rate look-back period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Look-Back Period Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Look-Back Period Weighted-average per unit or share fair value (in USD per share) Expected term Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Dividend rate (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Risk free interest rate, minimum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Risk free interest rate, maximum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Expected price volatility, minimum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Expected price volatility, maximum (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Age of grantee at which LTIP unit and restricted stock awards immediately vest Share-based Payment Arrangement by Share-based Payment Award, Equity Other than Options, Vesting Threshold, Age of Grantee Share-based Payment Arrangement by Share-based Payment Award, Equity Other than Options, Vesting Threshold, Age of Grantee Period of service, upon completion of which, grantee's LTIP unit and restricted stock awards will immediately vest (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Noncash share-based compensation expense recognized Share-based Payment Arrangement, Expense Unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Unrecognized compensation expense, period for recognition Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Debt Debt Disclosure [Text Block] Payables and Accruals [Abstract] Accounts Payable and Accrued Expenses Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Financing costs Debt Issuance Costs, Gross Less: accumulated amortization Accumulated Amortization, Debt Issuance Costs Total deferred financing costs, net Debt Issuance Costs, Net Amortization expense related to deferred financing costs Amortization of Debt Issuance Costs Remainder of 2020 Lessor, Operating Lease, Payments to be Received, Remainder of Fiscal Year 2021 Lessor, Operating Lease, Payments to be Received, Two Years 2022 Lessor, Operating Lease, Payments to be Received, Three Years 2023 Lessor, Operating Lease, Payments to be Received, Four Years 2024 Lessor, Operating Lease, Payments to be Received, Five Years Thereafter Lessor, Operating Lease, Payments to be Received, Thereafter Total future minimum lease payments on non-cancellable operating leases to be received Lessor, Operating Lease, Payments to be Received Accounting Policies [Table] Accounting Policies [Table] Accounting Policies [Table] Accounting Policies [Line Items] Accounting Policies [Line Items] [Line Items] for Accounting Policies [Table] Observatory revenue realized during the first quarter, previous ten years (as a percent) Historical Revenue Trend, Observatory Revenue, in Quarter One Over Ten Year Period, Percent Historical Revenue Trend, Observatory Revenue, in Quarter One Over Ten Year Period, Percent Observatory revenue realized during the second quarter, previous ten years (as a percent) Historical Revenue Trend, Observatory Revenue, in Quarter Two Over Ten Year Period, Percent Historical Revenue Trend, Observatory Revenue, in Quarter Two Over Ten Year Period, Percent Observatory revenue realized during the third quarter, previous ten years (as a percent) Historical Revenue Trend, Observatory Revenue, in Quarter Three Over Ten Year Period, Percent Historical Revenue Trend, Observatory Revenue, in Quarter Three Over Ten Year Period, Percent Observatory revenue realized during the fourth quarter, previous ten years (as a percent) Historical Revenue Trend, Observatory Revenue, in Quarter Four Over Ten Year Period, Percent Historical Revenue Trend, Observatory Revenue, in Quarter Four Over Ten Year Period, Percent Acquired below-market ground leases Ground Leases, Net [Abstract] Acquired below-market ground leases, gross Ground Leases, Gross Less: accumulated amortization Ground Leases, Accumulated Amortization Acquired below-market ground leases, net Ground Leases, Net Acquired below-market leases Below Market Lease, Net [Abstract] Acquired below-market leases, gross Below Market Lease, Gross Less: accumulated amortization Below Market Lease, Accumulated Amortization Acquired below-market leases, net Below Market Lease, Net Income Statement [Abstract] Revenues: Rental revenue Observatory revenue Lease termination fees Third-party management and other fees Other revenue and fees Operating expenses: Property operating expenses Ground rent expenses General and administrative expenses Observatory expenses Real estate taxes Depreciation and amortization Other income (expense): Interest income Interest expense Income tax expense Private perpetual preferred unit distributions Preferred Stock Dividends and Other Adjustments Net income attributable to common unitholders Net Income (Loss) Available to Common Stockholders, Basic Total weighted average units: Weighted Average Number of Shares Outstanding, Basic [Abstract] Basic (in units) Weighted Average Number of Shares Outstanding, Basic Diluted (in units) Weighted Average Number of Shares Outstanding, Diluted Earnings per unit attributable to common unitholders: Earnings Per Share [Abstract] Basic (in USD per unit) Earnings Per Share, Basic Diluted (in USD per unit) Earnings Per Share, Diluted Dividends per unit (in USD per unit) Common Stock, Dividends, Per Share, Declared Line of Credit Facility [Table] Line of Credit Facility [Table] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Forecast Forecast [Member] Unsecured Revolving Credit Facility and Term Loan Unsecured Revolving Credit Facility And Term Loan [Member] Unsecured Revolving Credit Facility And Term Loan [Member] Term loan facility Term Loan [Member] Term Loan [Member] Unsecured term loan facility Unsecured Term Loan [Member] Unsecured Term Loan [Member] Revolving Credit Facility Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Unsecured revolving credit facility, higher borrowing capacity option Line of Credit Facility, Higher Borrowing Capacity Option Line of Credit Facility, Higher Borrowing Capacity Option Outstanding borrowings Long-term Debt Number of options to extend maturity Debt Instrument, Option to Extend, Number Debt Instrument, Option to Extend, Number Extension period (in months) Line of Credit Facility, Extension Period Line of Credit Facility, Extension Period Extension fee, as a percent of outstanding commitments under revolving credit facility (percentage) Line of Credit Facility, Extension Fee, Percent of Outstanding Commitments Under Revolving Credit Facility Line of Credit Facility, Extension Fee, Percent of Outstanding Commitments Under Revolving Credit Facility Prepayment fee, percent of principal amount prepaid Line of Credit Facility, Prepayment Fee, Percent Of Principal Amount Prepaid Line of Credit Facility, Prepayment Fee, Percent Of Principal Amount Prepaid Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Estimated capital expenditures to be incurred Unfunded Capital Expenditures Unfunded Capital Expenditures Segment Reporting Segment Reporting Disclosure [Text Block] Metro Center Metro Center Debt [Member] Fixed Rate Debt - Metro Center Debt [Member] 10 Union Square Fixed Rate Debt, 10 Union Square [Member] Fixed Rate Debt, 10 Union Square [Member] 1542 Third Avenue Fixed Rate Debt, 1542 Third Avenue [Member] Fixed Rate Debt, 1542 Third Avenue [Member] First Stamford Place Fixed Rate Debt, First Stamford Place [Member] Fixed Rate Debt, First Stamford Place [Member] First Stamford Place - First Lien Fixed Rate Debt, First Stamford Place - First Lien [Member] Fixed Rate Debt, First Stamford Place - First Lien [Member] First Stamford Place - Second Lien Fixed Rate Debt, First Stamford Place - Second Lien [Member] First Stamford Place - Second Lien [Member] 1010 Third Avenue and 77 West 55th Street Fixed Rate Debt, 1010 Third Avenue and 77 West 55th Street [Member] Fixed Rate Debt, 1010 Third Avenue and 77 West 55th Street [Member] 10 Bank Street Fixed Rate Debt, 10 Bank Street [Member] Fixed Rate Debt, 10 Bank Street [Member] 383 Main Avenue Fixed Rate Debt, 383 Main Avenue [Member] Fixed Rate Debt, 383 Main Avenue [Member] 1333 Broadway Fixed Rate Debt - 1333 Broadway [Member] Fixed Rate Debt - 1333 Broadway [Member] Senior unsecured notes, Series A Series A Senior Notes due 2025 [Member] Series A Senior Notes due 2025 [Member] Senior unsecured notes, Series B Series B Senior Notes due 2027 [Member] Series B Senior Notes due 2027 [Member] Senior unsecured notes, Series C Series C Senior Notes due 2030 [Member] Series C Senior Notes due 2030 [Member] Senior unsecured notes, Series D Series D Senior Notes due 2028 [Member] Series D Senior Notes due 2028 [Member] Senior unsecured notes, Series E Series E Senior Notes due 2030 [Member] Series E Senior Notes due 2030 [Member] Senior unsecured notes, Series F Series F Senior Notes due 2033 [Member] Series F Senior Notes due 2033 [Member] Unsecured term loan facilities Mortgages Mortgages [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Fixed rate mortgage debt Long-term Debt, Percentage Bearing Fixed Interest, Amount Total Unsecured facility Long-term Line of Credit Total principal Long-term Debt, Gross Deferred financing costs, net Effective Rate (as a percentage) Debt Instrument, Interest Rate, Effective Percentage Basis spread on variable rate (as a percentage) Debt Instrument, Basis Spread on Variable Rate Accounts Payable and Accrued Expenses Accounts Payable and Accrued Liabilities Disclosure [Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Interest Rate Swap, One Month LIBOR, 2.1485% Interest Rate Swap, One Month LIBOR, 2.1485% [Member] Interest Rate Swap, One Month LIBOR, 2.1485% [Member] Interest Rate Swap, Three Month LIBOR, 2.9580% Interest Rate Swap, Three Month LIBOR, 2.9580%, Interest Swap Number Two [Member] Interest Rate Swap, Three Month LIBOR, 2.9580%, Interest Swap Number Two [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Notional Amount Derivative Liability, Notional Amount Pay Rate Derivative, Fixed Interest Rate Asset Derivative Asset, Fair Value, Gross Asset Liability Derivative Asset, Fair Value, Gross Liability Statement of Financial Position [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] ESRT Parent Company [Member] Private Perpetual Preferred Units, Series 2019 Private Perpetual Preferred Units, Series 2019 [Member] Private Perpetual Preferred Units, Series 2019 [Member] Private Perpetual Preferred Units, Series 2014 Private Perpetual Preferred Units, Series 2014 [Member] Private Perpetual Preferred Units, Series 2014 [Member] Series PR Operating Partnership Units Series ES operating partnership units Series 60 operating partnership units Series 250 operating partnership units Capital Partners' Capital [Abstract] Private perpetual preferred units, liquidation preference (in USD per share) Private Perpetual Preferred Units, Liquidation Preference Per Share Private Perpetual Preferred Units, Liquidation Preference Per Share Private perpetual preferred units, issued (in shares) Private Perpetual Preferred Units, Issued, Shares Private Perpetual Preferred Units, Issued, Shares Private perpetual preferred units, outstanding (in shares) Private Perpetual Preferred Units, Outstanding, Shares Private Perpetual Preferred Units, Outstanding, Shares General partner operating partnership units, outstanding (in shares) General Partners' Capital Account, Units Outstanding Limited partner operating partnership units, outstanding (in shares) Limited Partners' Capital Account, Units Outstanding Amortization Long Term Debt Fiscal Year Maturity, Amortization [Abstract] Long Term Debt Fiscal Year Maturity, Amortization [Abstract] 2019 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Portion Attributable to Amortization 2020 Long-term Debt, Maturities, Repayments of Principal in Year Two, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal in Year Two, Portion Attributable to Amortization 2021 Long-term Debt, Maturities, Repayments of Principal in Year Three, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal in Year Three, Portion Attributable to Amortization 2022 Long-term Debt, Maturities, Repayments of Principal in Year Four, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal in Year Four, Portion Attributable to Amortization 2023 Long-term Debt, Maturities, Repayments of Principal in Year Five, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal in Year Five, Portion Attributable to Amortization Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal after Year Five, Portion Attributable to Amortization Total Long-term Debt, Maturities, Repayments of Principal, Portion Attributable to Amortization Long-term Debt, Maturities, Repayments of Principal, Portion Attributable to Amortization Maturities Long Term Debt Fiscal Year Maturity, Maturities [Abstract] Long Term Debt Fiscal Year Maturity, Maturities [Abstract] 2019 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Principal Maturities Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months, Principal Maturities 2020 Long-term Debt, Maturities, Repayments of Principal in Year Two, Principal Maturities Long-term Debt, Maturities, Repayments of Principal in Year Two, Principal Maturities 2021 Long-term Debt, Maturities, Repayments of Principal in Year Three, Principal Maturities Long-term Debt, Maturities, Repayments of Principal in Year Three, Principal Maturities 2022 Long-term Debt, Maturities, Repayments of Principal in Year Four, Principal Maturities Long-term Debt, Maturities, Repayments of Principal in Year Four, Principal Maturities 2023 Long-term Debt, Maturities, Repayments of Principal in Year Five, Principal Maturities Long-term Debt, Maturities, Repayments of Principal in Year Five, Principal Maturities Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five, Principal Maturities Long-term Debt, Maturities, Repayments of Principal after Year Five, Principal Maturities Total Long-term Debt, Maturities, Repayments of Principal, Principal Maturities Long-term Debt, Maturities, Repayments of Principal, Principal Maturities Total Long-term Debt, Fiscal Year Maturity [Abstract] 2019 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2020 Long-term Debt, Maturities, Repayments of Principal in Year Two 2021 Long-term Debt, Maturities, Repayments of Principal in Year Three 2022 Long-term Debt, Maturities, Repayments of Principal in Year Four 2023 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Empire State Realty OP Empire State Realty OP [Member] Empire State Realty OP [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Empire State Realty Trust Empire State Realty Trust [Member] Empire State Realty Trust [Member] Other Partners, Certain Directors, Officers And Other Members Of Executive Management Other Partners, Certain Directors, Officers And Other Members Of Executive Management [Member] Other Partners, Certain Directors, Officers And Other Members Of Executive Management [Member] Shares and Units [Abstract] Partners' Capital Account, Units, Sale of Units [Abstract] OP units outstanding (in shares) Units of Partnership Interest, Amount OP units owned by the Company (in shares) OP units owned by the Company (as a percent) Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest OP units not owned by the Company (in shares) OP units not owned by the Company (as a percent) Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest Dividends on common stock received until performance criteria met for LTIP units (as a percent) Percentage of Dividends on Common Stock Received Until Performance Criteria Met for LTIP Units Percentage of Dividends on Common Stock Received Until Performance Criteria Met for LTIP Units Dividends on common stock received after performance criteria met for LTIP units (as a percent) Percentage of Dividends on Common Stock Received After Performance Criteria Met for LTIP Units Percentage of Dividends on Common Stock Received After Performance Criteria Met for LTIP Units Dividends on common stock received in periods after performance criteria met for LTIP units (as a percent) Percentage of Dividends on Common Stock Received In Periods After Performance Criteria Met for LTIP Units Percentage of Dividends on Common Stock Received In Periods After Performance Criteria Met for LTIP Units Private perpetual preferred units issued during period (in shares) Private Perpetual Preferred Units Issued During Period, Units, New Issues Private Perpetual Preferred Units Issued During Period, Units, New Issues Preferred units cumulative cash distributions (in USD per share) Preferred Units, Cumulative Cash Distributions, Per Share Preferred Units, Cumulative Cash Distributions, Per Share Dividends declared (in USD per share) Remainder of 2020 Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2021 Lessee, Operating Lease, Liability, Payments, Due Year Two 2022 Lessee, Operating Lease, Liability, Payments, Due Year Three 2023 Lessee, Operating Lease, Liability, Payments, Due Year Four 2024 Lessee, Operating Lease, Liability, Payments, Due Year Five Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total undiscounted cash flows Lessee, Operating Lease, Liability, Payments, Due Present value discount Lessee, Operating Lease, Liability, Undiscounted Excess Amount Ground lease liabilities Operating Lease, Liability Organization, Consolidation and Presentation of Financial Statements [Abstract] Description of Business and Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Senior unsecured notes - Series A, B, C, D, E, F, G and H Series A, Series B, Series C, Series D, Series E, Series F, Series G, And Series H Senior Unsecured Notes [Member] Series A, Series B, Series C, Series D, Series E, Series F, Series G, And Series H Senior Unsecured Notes [Member] Senior unsecured notes - Series A, B, C, D, E and F Series A, Series B, Series C, Series D, Series E And Series F Senior Unsecured Notes [Member] Series A, Series B, Series C, Series D, Series E And Series F Senior Unsecured Notes Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Estimated Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Interest rate swaps included in accounts payable and accrued expenses Derivative Liability Long-term debt, fair value Long-term Debt, Fair Value Accrued capital expenditures Accrued Liabilities, Capital Expenditures Accrued Liabilities, Capital Expenditures Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities Interest rate swap agreements liability Accrued interest payable Interest Payable Due to affiliated companies Due to Related Parties Total accounts payable and accrued expenses Accounts Payable and Accrued Expenses Accounts Payable and Accrued Expenses Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Organization, Consolidation and Presentation of Financial Statements Disclosure [Table] Organization, Consolidation and Presentation of Financial Statements Disclosure [Table] Organization, Consolidation and Presentation of Financial Statements Disclosure [Table] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Real Estate [Domain] Real Estate [Domain] Office Building Office Building [Member] Development Parcel Development Parcel [Member] Development Parcel [Member] Retail Site Retail Site [Member] Other Property Other Property [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Manhattan and Westport, Connecticut Manhattan and Westport, Connecticut [Member] Manhattan and Westport, Connecticut [Member] Manhattan Manhattan [Member] Manhattan [Member] Westport, Connecticut Westport, Connecticut [Member] Westport, Connecticut [Member] Fairfield County, Connecticut and Westchester County, New York Fairfield County, Connecticut and Westchester County, New York [Member] Fairfield County, Connecticut and Westchester County, New York [Member] Stamford, Connecticut Stamford, Connecticut [Member] Stamford, Connecticut [Member] Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] [Line Items] for Organization, Consolidation and Presentation of Financial Statements Disclosure [Table] Area of real estate property (in square feet) Area of Real Estate Property Number of properties Number of Real Estate Properties Components of Segment Profit for Each Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Capital Stockholders' Equity Note Disclosure, Disclosure of Compensation Related Costs, Share-based Payments and Earnings Per Share [Text Block] Stockholders' Equity Note Disclosure, Disclosure of Compensation Related Costs, Share-based Payments and Earnings Per Share [Text Block] Numerator: Net Income (Loss) Available to Common Stockholders, Basic and Diluted [Abstract] Net Income (Loss) Available to Common Stockholders, Basic and Diluted [Abstract] Private perpetual preferred unit distributions Earnings allocated to unvested units Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Net income attributable to common unitholders - basic and diluted Net Income Loss Excluding Portion Attributable to Noncontrolling Interest and Participating Securities Basic and Diluted Net Income Loss Excluding Portion Attributable to Noncontrolling Interest and Participating Securities Basic and Diluted Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted average units outstanding - basic (in units) Effect of dilutive securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Stock-based compensation plans (in units) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average units outstanding - diluted (in units) Earnings per share: Antidilutive securities (in units) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Statement of Cash Flows [Abstract] Cash Flows From Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Amortization of non-cash items within interest expense Amortization of Debt Issuance Costs and Discounts Amortization of acquired above- and below-market leases, net Amortization of acquired below-market ground leases Amortization of below Market Ground Lease Amortization of below Market Ground Lease Straight-lining of rental revenue Straight Line Rent Equity based compensation Share-based Payment Arrangement, Noncash Expense Increase (decrease) in cash flows due to changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Security deposits Increase (Decrease) in Security Deposits Tenant and other receivables Increase (Decrease) in Accounts Receivable Deferred leasing costs Increase (Decrease) in Deferred Leasing Fees Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Expenses Increase (Decrease) in Accounts Payable and Accrued Expenses Deferred revenue and other liabilities Increase (Decrease) in Deferred Revenue and Other Liabilities Increase (Decrease) in Deferred Revenue and Other Liabilities Loss on early extinguishment of debt Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash Flows From Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Short-term investments Payments for (Proceeds from) Short-term Investments Development costs Development Costs, Investing Activity Development Costs, Investing Activity Additions to building and improvements Payments for Capital Improvements Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash Flows From Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Repayment of mortgage notes payable Repayments of Notes Payable Proceeds from unsecured senior notes Proceeds from Issuance of Senior Long-term Debt Repayment of unsecured term loan Repayments From Unsecured Debt, Term Loan Repayments From Unsecured Debt, Term Loan Proceeds from unsecured term loan Proceeds from Unsecured Debt, Term Loan Proceeds from Unsecured Debt, Term Loan Proceeds from unsecured revolving credit facility Proceeds from Long-term Lines of Credit Repurchases of common units Payments for Repurchase of Common Stock Deferred financing costs Payments of Financing Costs Distributions Payments of Dividends Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents and restricted cash—beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents and restricted cash—end of period Reconciliation of Cash and Cash Equivalents and Restricted Cash: Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract] Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Restricted cash at beginning of period Restricted Cash and Cash Equivalents Cash and cash equivalents at end of period Restricted cash at end of period Cash and cash equivalents and restricted cash Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Cash paid for income taxes Income Taxes Paid Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Building and improvements included in accounts payable and accrued expenses Commercial Real Estate Incurred but Not yet Paid Commercial Real Estate Incurred but Not yet Paid Write-off of fully depreciated assets Property, Plant And Equipment And Intangible Assets, Write-Off Property, Plant And Equipment And Intangible Assets, Write-Off Derivative instruments at fair values included in prepaid expenses and other assets Derivative Financial Instruments Included in Prepaid Expenses and Other Assets Derivative Financial Instruments Included in Prepaid Expenses and Other Assets Derivative instruments at fair values included in accounts payable and accrued expenses Derivative Financial Instruments Included in Accounts Payable and Accrued Expense Derivative Financial Instruments Included in Accounts Payable and Accrued Expense Conversion of limited partners' operating partnership units to ESRT partner's capital Conversion of Stock, Amount Converted Issuance of Series 2019 private perpetual preferred in exchange for common units Issuance Of Private Perpetual Preferred Units In Exchange For Operating Partnership Units Issuance Of Private Perpetual Preferred Units In Exchange For Operating Partnership Units Right of use assets Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Ground lease liabilities Noncash Change In Operating Lease Liability Noncash Change In Operating Lease Liability Deferred Costs, Acquired Lease Intangibles and Goodwill Other Assets Disclosure [Text Block] Operating Leases [Table] Operating Leases [Table] Operating Leases [Table] Operating Leases [Line Items] Operating Leases [Line Items] [Line Items] for Operating Leases [Table] Term of lease Lessor, Operating Lease, Term of Contract Number of properties subject to ground leases Number of Properties Subject to Ground Leases Right-of-use assets Operating Lease, Right-of-Use Asset Lease liabilities Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Weighted average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Financial Instruments and Fair Values Fair Value Disclosures [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Aggregate notional value Derivative, Notional Amount Net unrealized gain (loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Net loss to be reclassified into interest expense within the next 12 months Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Series PR Operating Partnership Units Series 250 operating partnership units ASSETS Assets [Abstract] Commercial real estate properties, at cost: Real Estate Investment Property, at Cost [Abstract] Land Land Development costs Development in Process Building and improvements Investment Building and Building Improvements Commercial real estate properties, at cost Real Estate Investment Property, at Cost Less: accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Commercial real estate properties, net Real Estate Investment Property, Net Cash and cash equivalents Restricted cash Tenant and other receivables Accounts and Financing Receivable, after Allowance for Credit Loss Deferred rent receivables Deferred Rent Receivables, Net Prepaid expenses and other assets Prepaid Expense and Other Assets Deferred costs, net Deferred Costs Acquired below-market ground leases, net Right of use assets Total assets LIABILITIES AND CAPITAL Liabilities and Equity [Abstract] Liabilities: Liabilities [Abstract] Mortgage notes payable, net Notes Payable Senior unsecured notes, net Convertible Debt Unsecured term loan facilities, net Unsecured Debt Unsecured revolving credit facility, net Accounts payable and accrued expenses Acquired below-market leases, net Deferred revenue and other liabilities Deferred Revenue and Other Liabilities Deferred Revenue and Other Liabilities Tenants’ security deposits Security Deposit Liability Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Capital: Private perpetual preferred units Private Perpetual Preferred Units, Issued, Value Private Perpetual Preferred Units, Issued, Value ESRT partner's capital (2,976,762 and 2,996,520 general partner operating partnership units and 174,151,247 and 178,897,876 limited partner operating partnership units outstanding in 2020 and 2019, respectively) General & Limited Partners Capital Account General & Limited Partners Capital Account Limited partner operating partnership units Limited Partners' Capital Account Total capital Total liabilities and capital Liabilities and Equity Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Cover [Abstract] Series 60 operating partnership units Document Type Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] New York State Supreme Court, New York County New York State Supreme Court, New York County [Member] New York State Supreme Court, New York County [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of participants opting out of settlement Loss Contingency, Number of Plaintiffs Opting Out of Settlement Loss Contingency, Number of Plaintiffs Opting Out of Settlement Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affliliated entity Affiliated Entity [Member] Undivided Interest Undivided Interest [Member] Chairman emeritus Board of Directors, Chairman Emeritus [Member] Board of Directors, Chairman Emeritus [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Supervisory fee revenue Supervisory Fee Revenue [Member] Supervisory Fee Revenue [Member] Property management fee revenue Property Management Fee Revenue [Member] Property Management Fee Revenue [Member] Leased space rental Leased Space Rental [Member] Leased space rental [Member] Annualized rent revenue Annualized Rent Revenue [Member] Annualized Rent Revenue [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Revenue from related parties Revenue from Related Parties Lease cancellation, notice period (in days) Lease Cancellation, Period of Notice Lease Cancellation, Period of Notice Percentage of lease space occupied by Chairman emeritus and employee Related Party Transaction, Percentage of Leased Space Occupied Related Party Transaction, Percentage of Leased Space Occupied Number of directors Number of Directors, General Partner in Investment Fund Owning More Than 10% Economic and Voting Interest in Tenant Number of Directors, General Partner in Investment Fund Owning More Than 10% Economic and Voting Interest in Tenant Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain (loss) on valuation of interest rate swap agreements Less: amount reclassified into interest expense Other comprehensive income (loss) Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest