Shareholders' Equity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	May 26, 2012	May 28, 2011
Components Of Shareholders Equity [Line Items]
Cash dividends	$ 47,341	$ 105,186
Special dividends, amount per share		$ 1.00
Dividend declared, per share	$ 0.25
Dividend payable date	Jul. 24, 2012
Dividend record date	Jul. 10, 2012
Dividend payable amount	15,684
Class A common stock shares repurchased	670
Class A common stock shares repurchase amount	$ 47,986
MSC Stock Repurchase Plan [Member]
Components Of Shareholders Equity [Line Items]
Maximum number of shares that may yet be repurchased	4,384