Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

v3.8.0.1
Long-Term Debt - Additional Information (Detail)
3 Months Ended 9 Months Ended
Mar. 27, 2017
USD ($)
Mar. 10, 2017
USD ($)
Sep. 30, 2016
USD ($)
May 09, 2013
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
Location
$ / shares
Sep. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Jul. 02, 2012
USD ($)
Debt Instrument [Line Items]                    
Loss on repurchase of debt instrument             $ 14,607,000      
Incremental interest expense         $ 700,000 $ 1,500,000 2,600,000 $ 4,100,000    
Net expense expected to be reclassified         800,000   800,000      
Derivative Instruments and Hedging Activities [Member]                    
Debt Instrument [Line Items]                    
Expense and (benefit) related to cash flow swaps not designated as hedges         (100,000) (200,000) (300,000) (400,000)    
Derivative Instruments and Hedging Activities [Member] | Interest Rate Swap and Interest Rate Cap [Member]                    
Debt Instrument [Line Items]                    
Derivative asset, fair value of interest rate swap and cap positions         1,400,000   1,400,000      
Derivative Instruments and Hedging Activities [Member] | Interest Rate Swap [Member]                    
Debt Instrument [Line Items]                    
Derivative liability, fair value of interest rate swap and cap positions                 $ 3,700,000  
Derivative Instruments and Hedging Activities [Member] | Other Current Assets [Member] | Interest Rate Swap and Interest Rate Cap [Member]                    
Debt Instrument [Line Items]                    
Derivative asset, fair value of interest rate swap and cap positions         500,000   500,000      
Derivative Instruments and Hedging Activities [Member] | Other Assets [Member] | Interest Rate Swap and Interest Rate Cap [Member]                    
Debt Instrument [Line Items]                    
Derivative asset, fair value of interest rate swap and cap positions         3,800,000   3,800,000      
Derivative Instruments and Hedging Activities [Member] | Other Assets [Member] | Interest Rate Swap [Member]                    
Debt Instrument [Line Items]                    
Derivative asset, fair value of interest rate swap and cap positions                 2,800,000  
Derivative Instruments and Hedging Activities [Member] | Other Accrued Liabilities [Member] | Interest Rate Swap and Interest Rate Cap [Member]                    
Debt Instrument [Line Items]                    
Derivative liability, fair value of interest rate swap and cap positions         1,800,000   1,800,000      
Derivative Instruments and Hedging Activities [Member] | Other Accrued Liabilities [Member] | Interest Rate Swap [Member]                    
Debt Instrument [Line Items]                    
Derivative liability, fair value of interest rate swap and cap positions                 4,100,000  
Derivative Instruments and Hedging Activities [Member] | Other Long-Term Liabilities [Member] | Interest Rate Swap and Interest Rate Cap [Member]                    
Debt Instrument [Line Items]                    
Derivative liability, fair value of interest rate swap and cap positions         1,100,000   1,100,000      
Derivative Instruments and Hedging Activities [Member] | Other Long-Term Liabilities [Member] | Interest Rate Swap [Member]                    
Debt Instrument [Line Items]                    
Derivative liability, fair value of interest rate swap and cap positions                 $ 2,400,000  
Mortgage Notes [Member]                    
Debt Instrument [Line Items]                    
Mortgage financing aggregate         $ 38,400,000   $ 38,400,000      
Number of operating locations related to mortgage financing | Location             7      
Debt weighted average interest rate on note         4.01%   4.01%      
Outstanding principal balance         $ 411,200,000   $ 411,200,000      
Percentage of operating locations related to mortgage financing             45.00%      
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         $ 113,600,000   $ 113,600,000      
Minimum EBTDAR to rent ratio         383.00%   383.00%      
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         236,300,000   236,300,000      
Letters of credit outstanding amount         17,300,000   17,300,000      
2016 Revolving Credit Facility         135,000,000   135,000,000      
Borrowing availability amount         $ 84,000,000   $ 84,000,000      
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 maturity date             Jul. 15, 2022      
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 maturity date             May 15, 2023      
Notes issued at a price of principal amount       100.00%            
Interest payable description             semi-annually in arrears on May 15 and November 15 of each year      
Outstanding notes repurchased amount     $ 10,700,000     $ 10,700,000   $ 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 maturity date             Mar. 15, 2027      
Notes issued at a price of principal amount   100.00%                
Interest payable description             semi-annually in arrears on March 15 and September 15 of each year      
Notes issued yield maturity, percentage   6.125%                
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 | $ / shares             $ 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