Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Thousands	Aug. 31, 2015	Aug. 31, 2014
Debt Instrument [Line Items]
Other	$ 40	$ 80
Total long-term debt	438,028	437,318
Less long-term debt due within one year	(9,790)	(9,791)
Long-term debt due after one year	428,238	427,527
2013 Fixed Rate Notes [Member]
Debt Instrument [Line Items]
Total long-term debt	155,000	155,000
2011 Fixed Rate Notes [Member]
Debt Instrument [Line Items]
Total long-term debt	272,488	$ 282,238
2011 Variable Rate Notes [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 10,500