EARNINGS PER SHARE (Schedule of the Computation of Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017
EARNINGS PER SHARE [Abstract]
Net income	$ 14,148	$ 27,219	$ 36,638	$ 52,088
Less: Allocation of income to unvested stockholders		(345)	(398)	(758)
Net earnings available to common stockholders	$ 14,148	$ 26,874	$ 36,240	$ 51,330
Basic weighted average shares outstanding	30,100	30,004	30,089	29,993
Add dilutive effect of stock options (two-class method)		4	1	4
Diluted average shares outstanding	30,100	30,008	30,090	29,997
Basic net income per share	$ 0.47	$ 0.90	$ 1.21	$ 1.72
Diluted net income per share	$ 0.47	$ 0.90	$ 1.21	$ 1.72