Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Jun. 30, 2012	Feb. 22, 2012 Common Class A [Member]	Feb. 22, 2012 Common Class B [Member]
Entity Registrant Name	LITHIA MOTORS INC
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding			22,946,314	2,762,261
Entity Public Float		$ 503,888,000
Amendment Flag	false
Entity Central Index Key	0001023128
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY