Note 1 - Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items]
Number of New Vehicle Brands	30lad_NumberOfNewVehicleBrands
Number of Stores	129us-gaap_NumberOfStores
Interest Costs Capitalized	$ 400,000us-gaap_InterestCostsCapitalized	$ 100,000us-gaap_InterestCostsCapitalized	$ 300,000us-gaap_InterestCostsCapitalized
Advertising Expense	46,700,000us-gaap_AdvertisingExpense	39,600,000us-gaap_AdvertisingExpense	31,900,000us-gaap_AdvertisingExpense
Cooperative Advertising Amount	16,300,000us-gaap_CooperativeAdvertisingAmount	11,800,000us-gaap_CooperativeAdvertisingAmount	9,600,000us-gaap_CooperativeAdvertisingAmount
Long-term Debt, Percentage Bearing Variable Interest, Amount	1,600,000,000
Product Warranty Accrual	$ 400,000us-gaap_ProductWarrantyAccrual	$ 500,000us-gaap_ProductWarrantyAccrual
Number of Reportable Segments	3us-gaap_NumberOfReportableSegments
Revolving Credit Facility [Member]
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items]
Number of Financial Institutions	16
Number of Manufacturer-Affiliated Finance Companies	7
Minimum [Member]
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.40%
Maximum [Member]
Note 1 - Summary of Significant Accounting Policies (Details) [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	3.00%

Name:	lad_Note1SummaryofSignificantAccountingPoliciesDetailsLineItems
Namespace Prefix:	lad_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the number of financial institutions that make up the syndicated credit facility.

+ References

No definition available.

+ Details

Name:	lad_NumberOfFinancialInstitutions
Namespace Prefix:	lad_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of manufacturer-affiliated finance companies who participate in the credit facility.

+ References

No definition available.

+ Details

Name:	lad_NumberOfManufacturerAffiliatedFinanceCompanies
Namespace Prefix:	lad_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of new vehicle brands sold by the Company's stores.

+ References

No definition available.

+ Details

Name:	lad_NumberOfNewVehicleBrands
Namespace Prefix:	lad_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 35

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848

+ Details

Name:	us-gaap_AdvertisingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total amount received by an entity from a vendor under a cooperative advertising arrangement that has been offset against advertising expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cooperative Advertising

-URI http://asc.fasb.org/extlink&oid=6509061

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 50

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6408645&loc=d3e63872-111659

+ Details

Name:	us-gaap_CooperativeAdvertisingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of interest capitalized during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Allowance for Funds Used during Construction

-URI http://asc.fasb.org/extlink&oid=6504829

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

+ Details

Name:	us-gaap_InterestCostsCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtPercentageBearingVariableInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of stores.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStores
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph 5

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(5))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

Name:	us-gaap_ProductWarrantyAccrual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: