Employee and Retiree Benefits (Postretirement Benefit Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May. 30, 2015	May. 31, 2014	May. 30, 2015	May. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Interest cost	$ 348	$ 380	$ 1,034	$ 1,160
Service cost	107	96	320	296
Amortization of prior service benfit	(1,459)	(1,482)	(4,079)	(4,168)
Amortization of net actuarial loss	399	274	1,066	803
Net periodic postretirement benefit income	(605)	(732)	(1,659)	(1,909)
Payments for postretirement health care	$ 231	$ 247	$ 707	$ 779