Postretirement And Other Employee Benefits (Net Periodic Benefit Cost) (Details) (USD $) In Thousands	12 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Postretirement And Other Employee Benefits
Service cost	$ 1,494	$ 1,389	$ 1,759
Interest cost	5,715	5,681	6,779
Expected long-term return on plan assets	(4,474)	(4,270)	(4,731)
Recognized actuarial loss	2,073	1,303	874
Net curtailment gain	(1,903)		(4,608)
Amortization of prior service cost	(27)	(115)	(39)
Net periodic benefit cost	$ 2,878	$ 3,988	$ 34