| Cover | Jul. 07, 2020 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 7, 2020 |
| Entity Registrant Name | LITHIA MOTORS INC |
| Entity Incorporation, State or Country Code | OR |
| Entity File Number | 001-14733 |
| Entity Tax Identification Number | 93-0572810 |
| Entity Address, Address Line One | 150 N. Bartlett Street |
| Entity Address, City or Town | Medford |
| Entity Address, State or Province | OR |
| Entity Address, Postal Zip Code | 97501 |
| City Area Code | 541 |
| Local Phone Number | 776-6401 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A common stock without par value |
| Trading Symbol | LAD |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001023128 |
| Amendment Flag | false |
