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. 25, 2018	May 26, 2018	Feb. 24, 2018	Nov. 25, 2017	Aug. 26, 2017	May 27, 2017	Feb. 25, 2017	Nov. 26, 2016	Aug. 25, 2018	Aug. 26, 2017	Aug. 27, 2016
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic									$ 163,895	$ 70,196	$ 125,026
As reported - Basic (in shares)									19,811	20,284	20,168
Add: Undistributed earnings allocated to unvested participating shares									$ 0	$ 362	$ 636
Less: Undistributed earnings reallocated to unvested participating shares									0	(343)	(602)
Diluted Income Per Share – Common Stock									$ 163,895	$ 69,837	$ 124,409
Diluted EPS – Common Stock (in shares)									19,963	20,276	20,154
Diluted EPS – Common Stock (in dollars per share)		$ (0.25)	$ 0.98						$ 8.21	$ 3.44	$ 6.17
Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic	$ 29,312	$ 30,034	$ 46,744	$ 27,384	$ (3,908)	$ 19,307	$ 17,836	$ 22,342	$ 133,802	$ 55,903	$ 99,282
As reported - Basic (in shares)	15,429	15,446	15,481	15,462	15,402	15,326	15,305	15,285	15,454	15,382	15,245
As reported - Basic (in dollars per share)	$ 1.90	$ 1.94	$ 3.02	$ 1.77	$ (0.25)	$ 1.26	$ 1.17	$ 1.46	$ 8.66	$ 3.63	$ 6.51
Add: effect of dilutive potential common shares									$ 0	$ 0	$ 0
Add: effect of dilutive potential common shares (in shares)									152	108	93
Diluted Income Per Share – Common Stock	$ 34,952	$ 36,359	$ 58,378	$ 34,206	$ (4,886)	$ 24,199	$ 22,362	$ 28,020
Diluted EPS – Common Stock (in shares)	19,335	19,687	20,463	20,434	20,220	20,279	20,263	20,249
Diluted EPS – Common Stock (in dollars per share)	$ 1.81	$ 1.85	$ 2.85	$ 1.67	$ (0.24)	$ 1.19	$ 1.10	$ 1.38
Class B Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
As reported – Basic	$ 5,640	$ 6,325	$ 11,634	$ 6,822	$ (978)	$ 4,883	$ 4,518	$ 5,668	$ 30,093	$ 13,915	$ 25,093
As reported - Basic (in shares)	3,711	4,087	4,816	4,816	4,818	4,846	4,846	4,847	4,357	4,786	4,816
As reported - Basic (in dollars per share)	$ 1.52	$ 1.55	$ 2.42	$ 1.42	$ (0.20)	$ 1.01	$ 0.93	$ 1.17	$ 6.91	$ 2.91	$ 5.21
Add: effect of dilutive potential common shares									$ 30,093	$ 13,915	$ 25,093
Add: effect of dilutive potential common shares (in shares)									4,357	4,786	4,816