Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

v3.7.0.1
Long-Term Debt - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Mar. 27, 2017
Mar. 10, 2017
Sep. 30, 2016
May 09, 2013
Jul. 02, 2012
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Debt Instrument [Line Items]                    
Loss on repurchase of debt instrument               $ 14,607,000    
Incremental interest expense           $ 700,000 $ 1,300,000 1,900,000 $ 2,500,000  
Net expense expected to be reclassified           1,100,000   1,100,000    
Derivative Instruments and Hedging Activities [Member]                    
Debt Instrument [Line Items]                    
Fair value of swap positions           1,300,000   1,300,000   $ 3,700,000
Expense and (benefit) related to cash flow swaps not designated as hedges           (100,000) $ (100,000) (300,000) $ (200,000)  
Derivative Instruments and Hedging Activities [Member] | Other Current Assets [Member]                    
Debt Instrument [Line Items]                    
Fair value of swap positions                   2,800,000
Derivative Instruments and Hedging Activities [Member] | Other Assets [Member]                    
Debt Instrument [Line Items]                    
Fair value of swap positions           2,400,000   2,400,000   2,800,000
Derivative Instruments and Hedging Activities [Member] | Other Accrued Liabilities [Member]                    
Debt Instrument [Line Items]                    
Fair value of swap positions           1,800,000   1,800,000   4,100,000
Derivative Instruments and Hedging Activities [Member] | Other Long-Term Liabilities [Member]                    
Debt Instrument [Line Items]                    
Fair value of swap positions           1,900,000   1,900,000   $ 2,400,000
Mortgage Notes [Member]                    
Debt Instrument [Line Items]                    
Mortgage financing aggregate           $ 32,500,000   $ 32,500,000    
Debt weighted average interest rate on note           4.01%   4.01%    
Outstanding principal balance           $ 425,300,000   $ 425,300,000    
Percentage of operating locations related to mortgage financing               50.00%    
Notes payable due date               between 2017 and 2033    
2016 Credit Facility [Member]                    
Debt Instrument [Line Items]                    
Maturity date of revolving credit facility and floor plan facility               Nov. 30, 2021    
Net income and retained earnings free of restrictions           $ 113,500,000   $ 113,500,000    
Minimum EBTDAR to rent ratio           388.00%   388.00%    
2016 Credit Facility [Member] | Required Ratio [Member]                    
Debt Instrument [Line Items]                    
Minimum EBTDAR to rent ratio           150.00%   150.00%    
2016 Revolving Credit Facility [Member]                    
Debt Instrument [Line Items]                    
Current borrowing capacity           $ 250,000,000   $ 250,000,000    
Maximum borrowing capacity           300,000,000   300,000,000    
Borrowing base           211,400,000   211,400,000    
Letters of credit outstanding amount           17,300,000   17,300,000    
2016 Revolving Credit Facility           0   0    
Borrowing availability amount           $ 194,100,000   $ 194,100,000    
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%   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    
Cash paid to extinguish of debt instrument including early redemption premium and accrued and unpaid interest $ 213,700,000                  
Loss on repurchase of debt instrument $ 14,600,000                  
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%   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    
Outstanding notes repurchased amount     $ 10,700,000              
Repurchase amount paid in cash, plus accrued and unpaid interest related thereto     $ 10,600,000              
6.125% Senior Subordinated Notes due 2027 [Member]                    
Debt Instrument [Line Items]                    
Principal amount   $ 250,000,000                
Stated interest rate on debt agreement   6.125%       6.125%   6.125%   6.125%
Notes issued at a price of principal amount   100.00%                
Notes issued yield maturity, percentage   6.125%                
Notes maturity date               Mar. 15, 2027    
Interest payable description               semi-annually in arrears on March 15 and September 15 of each year    
Notes redemption price percentage of the principal amount               100.00%    
Redemption Price               106.125%    
Notes redemption price percentage of the par value due to Change of Control               101.00%    
Debt instrument maximum allowed dividends per share               $ 0.12    
Restrictive covenants under credit facilities and 6.125% notes               Specifically, the indenture governing the 6.125% Notes limits Sonic’s ability to pay quarterly cash dividends on Sonic’s Class A and Class B common stock in excess of $0.12 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 6.125% Notes.    
Outstanding principal amount of the 6.125% notes               25.00%    
6.125% Senior Subordinated Notes due 2027 [Member] | Maximum [Member]                    
Debt Instrument [Line Items]                    
Notes redemption price percentage of the principal amount               35.00%    
6.125% Senior Subordinated Notes due 2027 [Member] | Minimum [Member]                    
Debt Instrument [Line Items]                    
Indebtedness with outstanding balance under other agreements               $ 50,000,000