Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 25, 2012		Aug. 27, 2011
Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) [Line Items]
Revenues	$ 1,355,515	$ 1,256,289		$ 1,134,126
Income before income taxes	187,609	150,734		120,572
Provision for income taxes	70,924	55,745		44,086
Net income	116,685	94,989		76,486
Income allocated to – basic
Income allocated to common stock - basic	116,685	94,989		76,486
Common Class B [Member]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 4.91	$ 4.01		$ 3.24
Income allocated to – basic
Income allocated to common stock - basic	22,913	18,630		15,104
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	4,666	4,643		4,658
Common Class B [Member] | First Quarter [Member]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.30	$ 1.09
Income allocated to – basic
Income allocated to common stock - basic	6,025	5,068
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	4,647	4,641
Common Class B [Member] | Second Quarter [Member]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.12	$ 0.81
Income allocated to – basic
Income allocated to common stock - basic	5,209	3,765
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	4,647	4,640
Common Class B [Member] | Third Quarter [Member]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.21	$ 1.16	[1]
Income allocated to – basic
Income allocated to common stock - basic	5,647	5,381	[1]
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	4,675	4,644	[1]
Common Class B [Member] | Fourth Quarter [Member]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.29	$ 0.95
Income allocated to – basic
Income allocated to common stock - basic	6,033	4,416
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	4,694	4,647
First Quarter [Member]
Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) [Line Items]
Revenues	332,569	313,025
Income before income taxes	50,426	41,785
Provision for income taxes	19,666	15,983
Net income	30,760	25,802
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.62	$ 1.37
Income per share – diluted
Income per share common stock - Diluted (in Dollars per share)	$ 1.54	$ 1.30
Income allocated to – basic
Income allocated to common stock - basic	24,191	20,258
Income allocated to – diluted
Income allocated to common stock - diluted	30,244	25,350
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	14,925	14,838
Weighted average number of shares outstanding – diluted
Weighted average number of shares outstanding - diluted (in Shares)	19,693	19,557
Second Quarter [Member]
Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) [Line Items]
Revenues	334,306	309,959
Income before income taxes	43,215	31,086
Provision for income taxes	16,573	11,890
Net income	26,642	19,196
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.40	$ 1.01
Income per share – diluted
Income per share common stock - Diluted (in Dollars per share)	$ 1.33	$ 0.96
Income allocated to – basic
Income allocated to common stock - basic	20,963	15,081
Income allocated to – diluted
Income allocated to common stock - diluted	26,196	18,863
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	14,962	14,873
Weighted average number of shares outstanding – diluted
Weighted average number of shares outstanding - diluted (in Shares)	19,747	19,605
Third Quarter [Member]
Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) [Line Items]
Revenues	335,764	320,931	[1]
Income before income taxes	45,831	42,360	[1]
Provision for income taxes	17,109	14,901	[1]
Net income	28,722	27,459	[1]
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.51	$ 1.45	[1]
Income per share – diluted
Income per share common stock - Diluted (in Dollars per share)	$ 1.43	$ 1.37	[1]
Income allocated to – basic
Income allocated to common stock - basic	22,638	21,587	[1]
Income allocated to – diluted
Income allocated to common stock - diluted	28,307	26,993	[1]
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	14,993	14,905	[1]
Weighted average number of shares outstanding – diluted
Weighted average number of shares outstanding - diluted (in Shares)	19,820	19,646	[1]
Fourth Quarter [Member]
Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (Unaudited) [Line Items]
Revenues	352,876	312,374
Income before income taxes	48,137	35,503
Provision for income taxes	17,576	12,971
Net income	30,561	22,532
Income per share – basic
Income per share common stock - basic (in Dollars per share)	$ 1.61	$ 1.19
Income per share – diluted
Income per share common stock - Diluted (in Dollars per share)	$ 1.52	$ 1.13
Income allocated to – basic
Income allocated to common stock - basic	24,123	17,717
Income allocated to – diluted
Income allocated to common stock - diluted	$ 30,178	$ 22,153
Weighted average number of shares outstanding – basic
Weighted average number of shares outstanding - basic (in Shares)	15,017	14,912
Weighted average number of shares outstanding – diluted
Weighted average number of shares outstanding - diluted (in Shares)	19,882	19,664

[1] In the third fiscal quarter of 2012, operating results benefited from a settlement of environmental litigation that resulted in the Company recording a $6.7 million pre-tax gain. This gain translated into a $0.21 benefit to the Company's diluted earnings per share.