Document And Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Jan. 31, 2016
Jun. 30, 2015
Document And Entity Information [Abstract]      
Entity Registrant Name CAI International, Inc.    
Entity Filer Category Accelerated Filer    
Entity Central Index Key 0001388430    
Entity Current Reporting Status Yes    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Amendment Flag false    
Document Type 10-K    
Document Fiscal Period Focus FY    
Document Period End Date Dec. 31, 2015    
Document Fiscal Year Focus 2015    
Current Fiscal Year End Date --12-31    
Entity Common Stock, Shares Outstanding   19,921,739  
Entity Public Float     $ 280.5