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		9 Months Ended
	May 26, 2012	May 28, 2011	May 26, 2012	May 28, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 27,459	$ 18,431	$ 72,457	$ 58,472
Weighted average number of shares - basic	19,936	19,867	19,907	19,847
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	21,587	14,453	56,926	45,810
Weighted average number of shares - basic	14,905	14,810	14,872	14,780
Earning per share - basic (in amounts per share)	$ 1.45	$ 0.98	$ 3.83	$ 3.10
Common Class B [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	5,381	3,635	14,214	11,555
Weighted average number of shares - basic	4,644	4,656	4,642	4,660
Earning per share - basic (in amounts per share)	$ 1.16	$ 0.78	$ 3.06	$ 2.48
Unvested Participating Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 491	$ 343	$ 1,317	$ 1,107
Weighted average number of shares - basic	387	401	393	407