Postretirement and Other Employee Benefits (Net Periodic Benefit Cost for Pension Plans) (Details 9) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Postretirement and Other Employee Benefits [Abstract]
Service cost	$ 883	$ 1,054	$ 1,225
Interest cost	4,844	5,554	6,819
Expected long-term return on plan assets	(5,560)	(5,778)	(6,167)
Recognized actuarial loss	1,046	1,723	2,817
Net curtailment gain		(2,542)	(107)
Amortization of prior service credit	(139)	(147)	(198)
Net periodic benefit cost	$ 1,074	$ (136)	$ 4,389