Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 29, 2020	Aug. 31, 2019	Aug. 25, 2018
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 113	$ 114	$ 115
Interest cost	131	260	257
Expected return on assets	(138)	(199)	(174)
Amortization of prior service cost	66	66	66
Amortization of unrecognized loss		51	102
Other events	12	503	96
Net periodic benefit cost	184	795	462
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	918	725	694
Interest cost	1,027	1,148	1,027
Expected return on assets		0	0
Amortization of prior service cost		0	0
Amortization of unrecognized loss	703	247	362
Other events		0	0
Net periodic benefit cost	$ 2,648	$ 2,120	$ 2,083