XML 36 R1.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Document and Entity Information - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Jan. 31, 2020
Jun. 30, 2019
Cover page.      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
Entity File Number 001-06064    
Entity Registrant Name ALEXANDERS INC    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 51-0100517    
Entity Address, Address Line One 210 Route 4 East,    
Entity Address, City or Town Paramus,    
Entity Address, State or Province NJ    
Entity Address, Postal Zip Code 07652    
City Area Code (201)    
Local Phone Number 587-8541    
Title of 12(b) Security Common Stock, $1 par value per share    
Trading Symbol ALX    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 785,470
Entity Common Stock, Shares Outstanding   5,107,290  
Documents Incorporated by Reference
Part III: Portions of the Proxy Statement for the Annual Meeting of Stockholders to be held on May 14, 2020.
 
 
 
 
 

    
Entity Central Index Key 0000003499    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Amendment Flag false    
Current Fiscal Year End Date --12-31