Represents the number of votes per class of common stock.

No definition available.

Name:	lad_CommonStockNumberOfVotes
Namespace Prefix:	lad_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of shares of one class common stock shares convertible into another class of common stock.

+ References

No definition available.

+ Details

Name:	lad_ConversionOfCommonStockShares
Namespace Prefix:	lad_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage number of shares of Class B common stock outstanding representing less than 1% of the total number of shares of common stock outstanding that would be subject to automatic conversion.

+ References

No definition available.

+ Details

Name:	lad_PercentageOfClassBCommonToTotalCommonStockSubjectToAutomaticConversion
Namespace Prefix:	lad_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of additional shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	lad_StockRepurchaseProgramNumberOfAdditionalSharesAuthorizedToBeRepurchased
Namespace Prefix:	lad_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of adjustment to stockholders' equity associated with an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

+ References

No definition available.

+ Details

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

- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

+ Details

Name:	us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareRepurchaseProgramAxis=lad_The2016StockRepurchaseAuthorizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 8 - Stockholders' Equity (Details Textual) $ / shares in Units, $ in Millions		12 Months Ended
	Jul. 20, 2012 shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 shares	Dec. 31, 2014 shares	Feb. 29, 2016 shares	Aug. 31, 2011 shares
Shares Paid for Tax Withholding for Share Based Compensation		94,826	77,649	106,772
Common Class A [Member]
Conversion of Common Stock Shares		1
Common Stock Number of Votes		1
Stock Repurchase Program, Number of Shares Authorized to be Repurchased					250,000,000	2,000,000
Stock Repurchase Program, Number of Additional Shares Authorized to be Repurchased	1,000,000
Common Class A [Member] \| Restricted Stock Units (RSUs) [Member]
Shares Paid for Tax Withholding for Share Based Compensation		94,826
Treasury Stock Acquired, Average Cost Per Share \| $ / shares		$ 90.46
Adjustments Related to Tax Withholding for Share-based Compensation \| $		$ 8.6
Common Class A [Member] \| The 2016 Stock Repurchase Authorization [Member]
Stock Repurchase Program, Authorized Amount \| $		$ 193.1
Common Class B [Member]
Percentage of Class B Common to Total Common Stock Subject to Automatic Conversion		1.00%
Common Stock Number of Votes		10