Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Thousands	Aug. 31, 2016	Aug. 31, 2015
Debt Instrument [Line Items]
Other		$ 40
Total long-term debt	$ 578,938	438,028
Less long-term debt due within one year	(1,417)	(9,790)
Long-term debt due after one year	577,521	428,238
2016 Fixed Rate Notes [Member]
Debt Instrument [Line Items]
Total long-term debt	423,938
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
2011 Variable Rate Notes [Member]
Debt Instrument [Line Items]
Total long-term debt		$ 10,500