| Cover | Jul. 21, 2021 | Apr. 21, 2021 |
| Entity Information [Line Items] | ||
| Document Type | 8-K | |
| Document Period End Date | Jul. 21, 2021 | |
| 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 | 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 |
