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Related Party Transactions Tax Protection Agreement (Details) (Affiliated Entity [Member], USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
property
Related Party Transaction [Line Items]  
Number of properties protected 4esrt_RelatedPartyTransactionNumberofPropertiesProtected
Aggregate number of operating partnership units and common stock threshold during tax protection period 50.00%esrt_RelatedPartyTransactionAggregateNumberofOperatingPartnershipUnitsandCommonStockThresholdDuringTaxProtectionPeriod
Bottom dollar guarantee of aggregate indebtedness during tax protection period $ 160.0esrt_RelatedPartyTransactionBottomDollarGuaranteeofAggregateIndebtednessDuringtaxProtectionPeriod
Other Protected Property [Member]
  
Related Party Transaction [Line Items]  
Number of properties protected 3esrt_RelatedPartyTransactionNumberofPropertiesProtected
/ us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis
= esrt_OtherProtectedPropertyMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember