Pension and Savings Plans - Plan's Funded Status and Amounts Recognized in Company's Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Aug. 25, 2018	Aug. 25, 2018	Aug. 26, 2017	Aug. 27, 2016
Change in Projected Benefit Obligation:
Projected benefit obligation at beginning of year		$ 314,724	$ 328,511
Interest cost		10,356	10,335	$ 11,272
Actuarial (gains) losses		(676)	(8,746)
Annuities purchased		(157,589)
Benefits and settlements paid		(166,815)	(15,376)
Benefit obligations at end of year			314,724	328,511
Change in Plan Assets:
Fair value of plan assets at beginning of year		316,267	289,386
Actual return on plan assets		(3,428)	24,496
Employer contributions	$ 11,400	11,596	17,761
Annuities purchased		(157,589)
Benefits and settlements paid		(166,815)	(15,376)
Asset reversion upon termination		$ (31)
Fair value of plan assets at end of year			316,267	$ 289,386
Amount Recognized in the Statement of Financial Position:
Current liabilities			(283)
Long-term assets			8,686
Long-term liabilities			(6,860)
Net amount recognized			1,543
Amount Recognized in Accumulated Other Comprehensive Loss and not yet reflected in Net Periodic Benefit Cost:
Net actuarial loss			(118,889)
Accumulated other comprehensive loss			$ (118,889)