Net Income Per Share, Schedule of Earnings Per Share, Basic, Two Class Method (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 26, 2011	Nov. 27, 2010
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 25,802	$ 23,764
Weighted average number of shares - basic	19,877	19,828
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	20,258	18,604
Weighted average number of shares - basic	14,838	14,753
Earning per share - basic (in amounts per share)	$ 1.37	$ 1.26
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	5,068	4,704
Weighted average number of shares - basic	4,641	4,663
Earning per share - basic (in amounts per share)	$ 1.09	$ 1.01
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 476	$ 456
Weighted average number of shares - basic	398	412