Note 10. Long-term Debt (Detail) (USD $)	6 Months Ended
	Feb. 23, 2013
Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 250,000,000
Debt Instrument, Maturity Date	May 04, 2016
Debt Instrument, Interest Rate Terms	LIBOR plus 100 basis points at the time of the respective borrowing
Line of Credit Facility, Amount Outstanding	0
Letters of Credit Outstanding, Amount	47,000,000
Line of Credit Facility, Remaining Borrowing Capacity	203,000,000
Floating Rate Note [Member]
Debt Instrument, Maturity Date	Sep. 14, 2013
Debt Instrument, Interest Rate Terms	LIBOR plus 50 basis points
Proceeds from Issuance of Debt	$ 100,000,000