Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 25, 2018	Aug. 26, 2017	Aug. 27, 2016
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 115	$ 271	$ 204
Interest cost	257	244	307
Expected return on assets	(174)	(189)	(177)
Amortization of prior service cost	66	83	84
Amortization of unrecognized loss	102	149	105
Other events	96	125	43
Net periodic benefit cost	462	683	566
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	694	785	819
Interest cost	1,027	1,003	984
Expected return on assets	0	0	0
Amortization of prior service cost	0	56	368
Amortization of unrecognized loss	362	653	274
Other events	0	0	0
Net periodic benefit cost	$ 2,083	$ 2,497	$ 2,445