Impairment Of Long-Lived Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Impaired Long-Lived Assets Held and Used [Line Items]
Provisions for impairment of long-lived assets	$ 1,776	$ 764	$ 824
Change in vendor for the Sonic system's new point-of-sale technology [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Provisions for impairment of long-lived assets	1,600
Surplus Property [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Provisions for impairment of long-lived assets	$ 200