Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Additional Information (Detail)

v3.6.0.2
Long-Term Debt - Additional Information (Detail)
12 Months Ended
Nov. 30, 2016
USD ($)
Nov. 29, 2016
May 09, 2013
USD ($)
Jul. 02, 2012
USD ($)
shares
Dec. 31, 2016
USD ($)
Agreement
$ / shares
shares
Dec. 31, 2015
USD ($)
shares
Dec. 31, 2014
USD ($)
Debt Instrument [Line Items]              
Minimum EBTDAR to rent ratio         401.00%    
Notional Forward | Agreement         4    
Incremental interest expense         $ 5,500,000 $ 7,800,000 $ 10,700,000
Net expense expected to be reclassified         2,500,000    
Derivative Instruments and Hedging Activities [Member]              
Debt Instrument [Line Items]              
Fair value of swap positions         3,700,000 10,000,000  
Fair value of swap positions         2,800,000    
Benefits and charges related to cash flow swaps not designated as hedges         600,000 600,000 $ 500,000
Derivative Instruments and Hedging Activities [Member] | Other Accrued Liabilities [Member]              
Debt Instrument [Line Items]              
Fair value of swap positions         4,100,000 5,100,000  
Derivative Instruments and Hedging Activities [Member] | Other Long-Term Liabilities [Member]              
Debt Instrument [Line Items]              
Fair value of swap positions         $ 2,400,000 $ 4,900,000  
Mortgage Notes [Member]              
Debt Instrument [Line Items]              
Debt weighted average interest rate on note         3.74%    
Mortgage financing aggregate         $ 103,400,000    
Percentage of operating locations related to mortgage financing         45.00%    
Outstanding principal balance         $ 403,700,000    
Notes payable due date         between 2017 and 2033    
Required Ratio [Member]              
Debt Instrument [Line Items]              
Minimum EBTDAR to rent ratio         150.00%    
Common Class A [Member]              
Debt Instrument [Line Items]              
Common stock, shares issued | shares         62,967,061 62,586,381  
2014 Credit Facility [Member]              
Debt Instrument [Line Items]              
Maturity date of revolving credit facility and floor plan facility   Aug. 15, 2019     Nov. 30, 2021    
2016 Credit Facility [Member]              
Debt Instrument [Line Items]              
Maturity date of revolving credit facility and floor plan facility         Nov. 30, 2021    
Minimum EBTDAR to rent ratio         401.00%    
2016 Credit Facility [Member] | Required Ratio [Member]              
Debt Instrument [Line Items]              
Minimum EBTDAR to rent ratio         150.00%    
2016 Credit Facility [Member] | Minimum [Member]              
Debt Instrument [Line Items]              
Net income and retained earnings free of restrictions         $ 127,400,000    
2016 Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Increased availability under borrowing facility $ 25,000,000            
Current borrowing capacity         250,000,000    
Maximum borrowing capacity         300,000,000    
Borrowing base         228,500,000    
Letters of credit outstanding amount         21,400,000    
Revolving Credit Facility         0    
Borrowing availability amount         207,100,000    
2016 Floor Plan Facilities [Member]              
Debt Instrument [Line Items]              
Increased availability under borrowing facility $ 200,000,000            
Maximum borrowing capacity         1,015,000,000    
Increase in credit facility borrowing capacity         $ 1,265,000,000    
2016 Used Vehicle Floor Plan Facility [Member]              
Debt Instrument [Line Items]              
Allocation of credit facility increase, percentage         30.00%    
7.0% Senior Subordinated Notes Due 2022 [Member]              
Debt Instrument [Line Items]              
Principal amount       $ 200,000,000      
Stated interest rate on debt agreement       7.00% 7.00% 7.00%  
Notes issued at a price of principal amount       99.11%      
Notes issued yield maturity, percentage       7.125%      
Notes maturity date         Jul. 15, 2022    
Interest payable description         semi-annually in arrears on January 15 and July 15 of each year    
Notes redemption price percentage of the par value due to change of control         101.00%    
Debt instrument maximum allowed dividends per share | $ / shares         $ 0.10    
Restrictive covenants under 2011 credit facilities and 7 % notes with 5% notes         Specifically, the indenture governing the 7.0% Notes limits Sonic’s ability to pay quarterly cash dividends on Sonic’s Class A and Class B common stock in excess of $0.10 per share. Sonic may only pay quarterly cash dividends on Sonic’s Class A and Class B common stock if Sonic complies with the terms of the indenture governing the 7.0%    
Outstanding principal amount of the 7.0% notes         25.00%    
7.0% Senior Subordinated Notes Due 2022 [Member] | Minimum [Member]              
Debt Instrument [Line Items]              
Net income and retained earnings free of restrictions         $ 127,400,000    
Indebtedness with outstanding balance under other agreements         $ 35,000,000    
5.0% Convertible Senior Notes Due 2029 [Member] | Common Class A [Member]              
Debt Instrument [Line Items]              
Common stock, shares issued | shares       4,100,000      
5.0% Senior Subordinated Notes due 2023 [Member]              
Debt Instrument [Line Items]              
Principal amount     $ 300,000,000        
Stated interest rate on debt agreement     5.00%   5.00% 5.00%  
Notes issued at a price of principal amount     100.00%        
Notes maturity date         May 15, 2023    
Interest payable description         semi-annually in arrears on May 15 and November 15 of each year    
Notes redemption price percentage of the par value due to change of control         101.00%    
Debt instrument maximum allowed dividends per share | $ / shares         $ 0.10    
Restrictive covenants under 2011 credit facilities and 7 % notes with 5% notes         Specifically, the indenture governing the 5.0% Notes limits Sonic’s ability to pay quarterly cash dividends on Sonic’s Class A and Class B common stock in excess of $0.10 per share. Sonic may only pay quarterly cash dividends on Sonic’s Class A and Class B common stock if Sonic complies with the terms of the indenture governing the 5.0% Notes.    
Outstanding principal amount of the 7.0% notes         25.00%    
Outstanding notes repurchased amount         $ 10,700,000    
Repurchase amount paid in cash, plus accrued and unpaid interest related thereto         $ 10,600,000    
Notes redemption price percentage of the principal amount         100.00%    
5.0% Senior Subordinated Notes due 2023 [Member] | Minimum [Member]              
Debt Instrument [Line Items]              
Indebtedness with outstanding balance under other agreements         $ 50,000,000    
9.0% Senior Subordinated Notes due 2018 [Member]              
Debt Instrument [Line Items]              
Stated interest rate on debt agreement     9.00%        
Convertible senior notes due         2018