Goodwill and Intangible Assets	6 Months Ended
Goodwill and Intangible Assets	Jun. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	5. Goodwill and Intangible Assets The carrying amount of goodwill was approximately $471.5 million and $472.4 million, respectively, as of June 30, 2017 and December 31, 2016. Sonic impaired approximately $0.9 million of goodwill in the three and six months ended June 30, 2017 related to the closure of two stand-alone pre-owned stores that were purchased in 2016. The carrying amount of goodwill is net of accumulated impairment losses of approximately $797.6 million and $796.7 million, respectively, as of June 30, 2017 and December 31, 2016. The carrying amount of franchise assets was approximately $74.9 million as of both June 30, 2017 and December 31, 2016. At December 31, 2016, Sonic had approximately $5.3 million of definite life intangibles related to favorable lease agreements. After the effect of amortization of the definite life intangibles, the balance recorded at June 30, 2017 was approximately $5.0 million. Both franchise assets and favorable lease agreement assets are included in other intangible assets, net in the accompanying condensed consolidated balance sheets.

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.