v2.4.0.6
Document and Entity Information
6 Months Ended
Jun. 30, 2013
Aug. 02, 2013
Document Documentand Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2013  
Document Fiscal Year Focus 2013  
Document Fiscal Period Focus Q2  
Trading Symbol AAT  
Entity Registrant Name AMERICAN ASSETS TRUST, INC.  
Entity Central Index Key 0001500217  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   40,445,578