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v3.19.2

Stockholders' Equity (Details) $ in Millions | 3 Months Ended
--- | ---
Jun. 30, 2019 USD ($)
Equity [Abstract] |
Net premiums paid | $ 36.5

X
- Definition Adjustments to Additional Paid in Capital, Stock Repurchase, Option Premium Paid + References No definition available. + Details
Name: | lad_AdjustmentstoAdditionalPaidinCapitalStockRepurchaseOptionPremiumPaid
Namespace Prefix: | lad_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_EquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration