Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Revenues:
Company Drive-In sales	$ 404,443	$ 410,820	$ 414,369
Franchise Drive-Ins:
Franchise royalties	125,989	124,127	122,385
Franchise fees	2,024	1,744	2,752
Lease revenue	6,575	6,023	6,879
Other	4,699	3,237	4,541
Total revenues	543,730	545,951	550,926
Costs and expenses:
Food and packaging	113,775	115,516	114,281
Payroll and other employee benefits	144,531	149,417	145,688
Other operating expenses, exclusive of depreciation and amortization included below	89,164	91,303	94,690
Total cost of company drive-in sales	347,470	356,236	354,659
Selling, general and administrative	65,173	64,943	66,847
Depreciation and amortization	41,914	41,225	42,615
Provision for impairment of long-lived assets	764	824	15,161
Total costs and expenses	455,321	463,228	479,282
Other operating income (expense), net	531	585	(763)
Income from operations	88,940	83,308	70,881
Interest expense	31,608	32,600	36,707
Interest income	(630)	(706)	(948)
Net loss from early extinguishment of debt		23,035	314
Net interest expense	30,978	54,929	36,073
Income before income taxes	57,962	28,379	34,808
Provision for income taxes	21,877	9,154	8,969
Net income - including noncontrolling interests	36,085	19,225	25,839
Net income - noncontrolling interests			4,630
Net income - attributable to Sonic Corp.	$ 36,085	$ 19,225	$ 21,209
Basic income per share	$ 0.60	$ 0.31	$ 0.35
Diluted income per share	$ 0.60	$ 0.31	$ 0.34