Long-term Debt (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Feb. 25, 2012
Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit	$ 250,000
Maturity date	May 04, 2016
Terms	LIBOR plus 100 basis points at the time of the respective borrowing
Line of credit facility, amount outstanding	0
Outstanding letters of credit	43,200
Amount available for borrowing	206,800
Prior Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit	225,000
Maturity date	Sep. 13, 2011
Floating Rate Note [Member]
Debt Instrument [Line Items]
Maturity date	Sep. 14, 2013
Terms	LIBOR plus 50 basis points
Issuance of floating rate notes	$ 100,000
Debt instrument, maturity date range end	two years