XML 45 R34.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Business Acquisitions and Dispositions - Additional Information (Details) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2018 USD ($) Franchise Business | Mar. 31, 2017 USD ($) Franchise Business
Business Combinations [Abstract] |  |
Number of acquired franchises | Business | 0 | 0
Business Acquisition [Line Items] |  |
Number of franchises disposed |  | 0
Proceeds from sales of dealerships | $ | $ 7,461 | $ 0
Number of franchises terminated | 1 |
Luxury franchise |  |
Business Acquisition [Line Items] |  |
Number of franchises disposed | 1 |
Pre-Owned Stores Segment |  |
Business Acquisition [Line Items] |  |
Number of franchises ceased operations | 1 |

X
- Definition Number Of Franchises Ceased Operations + References No definition available. + Details
Name: | sah_NumberOfFranchisesCeasedOperations
Namespace Prefix: | sah_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of franchises disposed. + References No definition available. + Details
Name: | sah_NumberOfFranchisesDisposed
Namespace Prefix: | sah_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Franchises Terminated + References No definition available. + Details
Name: | sah_NumberOfFranchisesTerminated
Namespace Prefix: | sah_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition The number of businesses acquired by the entity during the period. + References No definition available. + Details
Name: | us-gaap_NumberOfBusinessesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the cash inflow during the period from the sale of a component of the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromDivestitureOfBusinessesNetOfCashDivested
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=sah_LuxuryFranchiseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=sah_PreOwnedStoresMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |