Postretirement and Other Employee Benefits (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2016	May 31, 2015
Postretirement and Other Employee Benefits [Abstract]
Service cost	$ 222	$ 256	$ 662	$ 803
Interest cost	1,208	1,384	3,693	4,267
Expected long-term return on plan assets	(1,383)	(1,440)	(4,243)	(4,431)
Recognized actuarial loss	264	479	790	1,491
Amortization of prior service cost	(35)	(35)	(104)	(114)
Net periodic benefit cost	$ 276	$ 644	$ 798	$ 2,016