XML 16 R1.htm IDEA: XBRL DOCUMENT v3.6.0.2
Document and Entity Information - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2016
Feb. 10, 2017
Jun. 30, 2016
Dec. 31, 2015
Document and Entity Information [Abstract]        
Entity Registrant Name GROUP 1 AUTOMOTIVE INC      
Entity Central Index Key 0001031203      
Document Type 10-K      
Document Period End Date Dec. 31, 2016      
Amendment Flag false      
Document Fiscal Year Focus 2016      
Document Fiscal Period Focus FY      
Current Fiscal Year End Date --12-31      
Entity Well-known Seasoned Issuer Yes      
Entity Voluntary Filers No      
Entity Current Reporting Status Yes      
Entity Filer Category Large Accelerated Filer      
Entity Public Float     $ 1,000.1  
Entity Common Stock, Shares Outstanding   21,383,593    
Common Stock, Par or Stated Value Per Share $ 0.01     $ 0.01