Capital Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Earnings Per Share [Abstract]
Earnings (loss) from continuing operations	$ 37,958	$ 50,557	$ (2,206)	$ 105,866
Weighted average common shares outstanding - basic	59,617	70,432	61,911	71,915
Net effect of dilutive securities—stock based compensation plans (1)	626	1,338	0	1,603
Weighted average common shares outstanding - diluted	60,243	71,770	61,911	73,518
Basic	$ 0.64	$ 0.72	$ (0.04)	$ 1.47
Diluted	$ 0.63	$ 0.70	$ (0.04)	$ 1.44
Anti-dilutive securities stock based compensation plans (excluded from earnings per share calculation)	2,256	463	4,662	558