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. 24, 2012	Nov. 26, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 30,760	$ 25,802
Weighted average number of shares - basic	19,955	19,877
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	24,191	20,258
Weighted average number of shares - basic	14,925	14,838
Earning per share - basic (in amounts per share)	$ 1.62	$ 1.37
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	6,025	5,068
Weighted average number of shares - basic	4,647	4,641
Earning per share - basic (in amounts per share)	$ 1.30	$ 1.09
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 544	$ 476
Weighted average number of shares - basic	383	398