Organization (Details) ft² in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015 ft² a aptunits property Segment	Dec. 31, 2001 a
Operating Properties [Abstract]
Number of properties in greater New York City metropolitan area (in property) | property		7
Number of Reportable Segments | Segment		1
Toys R Us/ Babies R Us [Member]
Operating Properties [Abstract]
Vornado's ownership interest in tenants		33.33%
731 Lexington Avenue [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		1,311
731 Lexington Avenue [Member] | Office Space [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		889
731 Lexington Avenue [Member] | Retail Space [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		174
731 Lexington Avenue [Member] | Retail Space [Member] | Tenant Occupant [Member] | Home Depot [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		83
731 Lexington Avenue [Member] | Retail Space [Member] | Tenant Occupant [Member] | Container Store [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		34
731 Lexington Avenue [Member] | Retail Space [Member] | Tenant Occupant [Member] | Hennes Mauritz [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		27
731 Lexington Avenue [Member] | Residential Space [Member] | Operating Property [Member]
Operating Properties [Abstract]
Number of units in real estate property (in units) | aptunits		105
Area of property (in square feet)		248
Rego Park I [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		343
Rego Park I [Member] | Tenant Occupant [Member] | Sears [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		195
Rego Park I [Member] | Tenant Occupant [Member] | Burlington Coat Factory [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		50
Rego Park I [Member] | Tenant Occupant [Member] | Bed Bath Beyond [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		46
Rego Park I [Member] | Tenant Occupant [Member] | Marshalls [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		36
Rego Park II [Member] | Retail Space [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		609
Rego Park II [Member] | Retail Space [Member] | Tenant Occupant [Member] | Costco [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		145
Rego Park II [Member] | Retail Space [Member] | Tenant Occupant [Member] | Century 21 [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		135
Rego Park II [Member] | Retail Space [Member] | Tenant Occupant [Member] | Kohls [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		133
Rego Park II [Member] | Retail Space [Member] | Tenant Occupant [Member] | Toys R Us/ Babies R Us [Member] | Anchor [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		47
Rego Park II [Member] | The Alexander apartment tower [Member] | Operating Property [Member]
Operating Properties [Abstract]
Number of units in real estate property (in units) | aptunits		312
Area of property (in square feet)		255
Real Estate Property Percentage In Service		93.00%
Number of units leased (in units) | aptunits		84
Rego Park II [Member] | The Alexander apartment tower [Member] | Operating Property [Member] | Scenario Forecast [Member]
Operating Properties [Abstract]
Real Estate Property Percentage In Service	7.00%
Paramus [Member] | Tenant Occupant [Member] | Ikea [Member]
Operating Properties [Abstract]
Area Of Land (in acre) | a			30.3
Paramus [Member] | Tenant Occupant [Member] | Ikea [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area Of Land (in acre) | a		30.3
Flushing [Member] | Tenant Occupant [Member] | New World Mall Llc [Member] | Operating Property [Member]
Operating Properties [Abstract]
Area of property (in square feet)		167
Rego Park III [Member] | Properties to be developed [Member]
Operating Properties [Abstract]
Area Of Land (in acre) | a		3.2