Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 28, 2015
Document and Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	SAH
Entity Registrant Name	SONIC AUTOMOTIVE INC
Entity Central Index Key	0001043509
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Common Class A [Member]
Document and Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		38,841,740
Common Class B [Member]
Document and Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		12,029,375