Annual report pursuant to Section 13 and 15(d)

Property and Equipment - Components of Property and Equipment, Net (Detail)

v2.4.1.9
Property and Equipment - Components of Property and Equipment, Net (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Property Plant And Equipment [Line Items]    
Total, at cost $ 1,115,936us-gaap_PropertyPlantAndEquipmentGross $ 1,006,147us-gaap_PropertyPlantAndEquipmentGross
Less accumulated depreciation (316,617)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment (300,035)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Subtotal 799,319sah_PropertyPlantAndEquipmentIncludingAssetsHeldForSaleNet 706,112sah_PropertyPlantAndEquipmentIncludingAssetsHeldForSaleNet
Less assets held for sale   (4,101)us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment
Property and Equipment, net 799,319us-gaap_PropertyPlantAndEquipmentNet 702,011us-gaap_PropertyPlantAndEquipmentNet
Land [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost 224,124us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember
194,639us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember
Building and Improvements [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost 582,261us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingImprovementsMember
569,619us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingImprovementsMember
Office Equipment and Fixtures [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost 151,165us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OfficeEquipmentMember
135,221us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_OfficeEquipmentMember
Parts and Service Equipment [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost 68,248us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= sah_PartsAndServiceEquipmentMember
70,950us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= sah_PartsAndServiceEquipmentMember
Company Vehicles [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost 8,958us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_VehiclesMember
8,002us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_VehiclesMember
Construction in Progress [Member]    
Property Plant And Equipment [Line Items]    
Total, at cost $ 81,180us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember
$ 27,716us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember