Sonic Automotive, Inc. Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Fair Value and Carrying Value of Fixed Rate Long-Term Debt (Parenthetical) (Detail)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 9.0% Senior Subordinated Notes due 2018 [Member]	Jun. 30, 2013 9.0% Senior Subordinated Notes due 2018 [Member]	Dec. 31, 2012 9.0% Senior Subordinated Notes due 2018 [Member]	Mar. 12, 2010 9.0% Senior Subordinated Notes due 2018 [Member]	Dec. 31, 2013 7.0% Senior Subordinated Notes due 2022 [Member]	Dec. 31, 2012 7.0% Senior Subordinated Notes due 2022 [Member]	Dec. 31, 2013 5.0% Senior Subordinated Notes due 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate on debt agreement	5.00%	5.00%	9.00%	9.00%	9.00%	9.00%	7.00%	7.00%	5.00%