Employee and Retiree Benefits (Postretirement Benefit Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 28, 2016	May 30, 2015	May 28, 2016	May 30, 2015
Compensation and Retirement Disclosure [Abstract]
Interest cost	$ 58	$ 348	$ 269	$ 1,034
Service cost	23	107	86	320
Amortization of prior service benfit	(2,008)	(1,459)	(5,728)	(4,079)
Amortization of net actuarial loss	415	399	1,197	1,066
Net periodic postretirement benefit income	(1,512)	(605)	(4,176)	(1,659)
Payments for postretirement health care	$ 232	$ 231	$ 738	$ 707