Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Aug. 26, 2017	May 27, 2017	Feb. 25, 2017	Nov. 26, 2016	Aug. 27, 2016	May 28, 2016	Feb. 27, 2016	Nov. 28, 2015	Aug. 26, 2017	Aug. 27, 2016	Aug. 29, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic									$ 70,196	$ 125,026	$ 124,299
As reported - Basic (in shares)									20,284	20,168	20,098
Add: Undistributed earnings allocated to unvested participating shares									$ 362	$ 636	$ 853
Less: Undistributed earnings reallocated to unvested participating shares									(343)	(602)	(807)
Diluted EPS – Common Stock									$ 69,837	$ 124,409	$ 123,472
Diluted EPS – Common Stock (in shares)									20,276	20,154	20,079
Diluted EPS – Common Stock (in dollars per share)									$ 3.44	$ 6.17	$ 6.15
Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic	$ (3,908)	$ 19,307	$ 17,836	$ 22,342	$ 28,097	$ 23,939	$ 18,691	$ 28,539	$ 55,903	$ 99,282	$ 98,665
As reported - Basic (in shares)	15,402	15,326	15,305	15,285	15,268	15,253	15,241	15,218	15,382	15,245	15,182
As reported - Basic (in dollars per share)	$ (0.25)	$ 1.26	$ 1.17	$ 1.46	$ 1.84	$ 1.57	$ 1.23	$ 1.88	$ 3.63	$ 6.51	$ 6.50
Add: effect of dilutive potential common shares									$ 0	$ 0	$ 0
Add: effect of dilutive potential common shares (in shares)									108	93	134
Diluted EPS – Common Stock	$ (4,886)	$ 24,199	$ 22,362	$ 28,020	$ 35,250	$ 30,007	$ 23,401	$ 35,741
Diluted EPS – Common Stock (in shares)	20,220	20,279	20,263	20,249	20,223	20,183	20,138	20,132
Diluted EPS – Common Stock (in dollars per share)	$ (0.24)	$ 1.19	$ 1.10	$ 1.38	$ 1.74	$ 1.49	$ 1.16	$ 1.78
Class B Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic	$ (978)	$ 4,883	$ 4,518	$ 5,668	$ 7,139	$ 6,061	$ 4,704	$ 7,193	$ 13,915	$ 25,093	$ 24,761
As reported - Basic (in shares)	4,818	4,846	4,846	4,847	4,850	4,827	4,795	4,795	4,786	4,816	4,763
As reported - Basic (in dollars per share)	$ (0.20)	$ 1.01	$ 0.93	$ 1.17	$ 1.47	$ 1.26	$ 0.98	$ 1.50	$ 2.91	$ 5.21	$ 5.20
Add: effect of dilutive potential common shares									$ 13,915	$ 25,093	$ 24,761
Add: effect of dilutive potential common shares (in shares)									4,786	4,816	4,763