v2.4.0.8
Document and Entity Information (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Feb. 24, 2014
Jun. 30, 2013
Document and Entity Information      
Entity Registrant Name AMERICAN STATES WATER CO    
Entity Central Index Key 0001056903    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Document Type 10-K    
Document Period End Date Dec. 31, 2013    
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   38,746,762  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 1,038,069