Organization	12 Months Ended
Dec. 31, 2011
Organization [Abstract]
Organization [Text Block]	1. ORGANIZATION Alexander's, Inc. (NYSE: ALX) is a real estate investment trust (“REIT”), incorporated in Delaware, engaged in leasing, managing, developing and redeveloping its properties. All references to “we,” “us,” “our,” “Company” and “Alexander's” refer to Alexander's, Inc. and its consolidated subsidiaries. We are managed by, and our properties are leased and developed by, Vornado Realty Trust (“Vornado”) (NYSE: VNO). We have seven properties in the greater New York City metropolitan area consisting of: Operating properties (i) the 731 Lexington Avenue property, a 1,307,000 square foot multi-use building, comprising the entire square block bounded by Lexington Avenue, East 59th Street, Third Avenue and East 58th Street in Manhattan. The building contains 885,000 and 174,000 of net rentable square feet of office and retail space, respectively, which we own, and 248,000 square feet of residential space consisting of 105 condominium units, which we sold. Bloomberg L.P. (“Bloomberg”) occupies all of the office space. The Home Depot (83,000 square feet), The Container Store (34,000 square feet) and Hennes & Mauritz (27,000 square feet) are the principal retail tenants; (ii) the Kings Plaza Regional Shopping Center contains 1,210,000 square feet and is located on Flatbush Avenue in Brooklyn. The center is anchored by a 339,000 square foot Macy's (owned by Macy's, Inc.), a 289,000 square foot Sears department store and a 114,000 square foot Lowe's; (iii) the Rego Park I Shopping Center contains 343,000 square feet and is located on Queens Boulevard and 63rd Road in Queens. The center is anchored by a 195,000 square foot Sears department store, a 50,000 square foot Burlington Coat Factory, a 46,000 square foot Bed Bath & Beyond and a 36,000 square foot Marshalls; (iv) the Rego Park II Shopping Center contains 610,000 square feet and is located adjacent to the Rego Park I Shopping Center in Queens. The center is anchored by a 145,000 square foot Costco, a 135,000 square foot Century 21 and a 133,000 square foot Kohl's. In addition, 47,000 square feet is leased to Toys “R” Us/Babies “R” Us, a one-third owned affiliate of Vornado; (v) the Paramus property, located at the intersection of Routes 4 and 17 in Paramus, New Jersey, consists of 30.3 acres of land leased to IKEA Property, Inc.; (vi) the Flushing property, a 167,000 square foot building, is located at Roosevelt Avenue and Main Street in Queens and is sub-leased to New World Mall LLC for the remainder of our ground lease term; and Property to be developed (vii) the Rego Park III property is a 3.4 acre land parcel adjacent to the Rego Park II Shopping Center in Queens at the intersection of Junction Boulevard and the Horace Harding Service Road. We have determined that our properties have similar economic characteristics and meet the criteria which permit the properties to be aggregated into one reportable segment (the leasing, management, development and redeveloping of properties in the greater New York City metropolitan area). Our chief operating decision-maker assesses and measures segment operating results based on a performance measure referred to as net operating income at the individual operating segment. Net operating income for each property represents net rental revenues less operating expenses.

Organization

12 Months Ended

Dec. 31, 2011

1. ORGANIZATION

Alexander's, Inc. (NYSE: ALX) is a real estate investment trust (“REIT”), incorporated in Delaware, engaged in leasing, managing, developing and redeveloping its properties. All references to “we,” “us,” “our,” “Company” and “Alexander's” refer to Alexander's, Inc. and its consolidated subsidiaries. We are managed by, and our properties are leased and developed by, Vornado Realty Trust (“Vornado”) (NYSE: VNO).

We have seven properties in the greater New York City metropolitan area consisting of:

Operating properties

(i) the 731 Lexington Avenue property, a 1,307,000 square foot multi-use building, comprising the entire square block bounded by Lexington Avenue, East 59th Street, Third Avenue and East 58th Street in Manhattan. The building contains 885,000 and 174,000 of net rentable square feet of office and retail space, respectively, which we own, and 248,000 square feet of residential space consisting of 105 condominium units, which we sold. Bloomberg L.P. (“Bloomberg”) occupies all of the office space. The Home Depot (83,000 square feet), The Container Store (34,000 square feet) and Hennes & Mauritz (27,000 square feet) are the principal retail tenants;

(ii) the Kings Plaza Regional Shopping Center contains 1,210,000 square feet and is located on Flatbush Avenue in Brooklyn. The center is anchored by a 339,000 square foot Macy's (owned by Macy's, Inc.), a 289,000 square foot Sears department store and a 114,000 square foot Lowe's;

(iii) the Rego Park I Shopping Center contains 343,000 square feet and is located on Queens Boulevard and 63rd Road in Queens. The center is anchored by a 195,000 square foot Sears department store, a 50,000 square foot Burlington Coat Factory, a 46,000 square foot Bed Bath & Beyond and a 36,000 square foot Marshalls;

(iv) the Rego Park II Shopping Center contains 610,000 square feet and is located adjacent to the Rego Park I Shopping Center in Queens. The center is anchored by a 145,000 square foot Costco, a 135,000 square foot Century 21 and a 133,000 square foot Kohl's. In addition, 47,000 square feet is leased to Toys “R” Us/Babies “R” Us, a one-third owned affiliate of Vornado;

(v) the Paramus property, located at the intersection of Routes 4 and 17 in Paramus, New Jersey, consists of 30.3 acres of land leased to IKEA Property, Inc.;

(vi) the Flushing property, a 167,000 square foot building, is located at Roosevelt Avenue and Main Street in Queens and is sub-leased to New World Mall LLC for the remainder of our ground lease term; and

Property to be developed

(vii) the Rego Park III property is a 3.4 acre land parcel adjacent to the Rego Park II Shopping Center in Queens at the intersection of Junction Boulevard and the Horace Harding Service Road.

We have determined that our properties have similar economic characteristics and meet the criteria which permit the properties to be aggregated into one reportable segment (the leasing, management, development and redeveloping of properties in the greater New York City metropolitan area). Our chief operating decision-maker assesses and measures segment operating results based on a performance measure referred to as net operating income at the individual operating segment. Net operating income for each property represents net rental revenues less operating expenses.