EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Aug. 31, 2014	May 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013		May 31, 2013		Feb. 28, 2013		Nov. 30, 2012		Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2014	Aug. 31, 2013		Aug. 31, 2012
Earnings Per Share [Abstract]
Net income from continuing operations	$ 21,856	$ 21,320	$ 28,278	$ 21,432	$ 20,839	[1]	$ 18,539	[1]	$ 24,882	[1]	$ 20,005	[1]	$ 17,725	$ 15,708	$ 20,217	$ 13,996	$ 92,886	$ 84,265	[1]	$ 67,646
Less: Allocation of income to unvested stockholders																	(1,652)	(1,780)		(1,337)
Net earnings available to common stockholders from continuing operations																	91,234	82,485		66,309
Net earnings (loss) available to common stockholders from discontinued operations													$ (19)	$ (2)	$ 3	$ (7)	$ 0	$ 0		$ (25)
Basic weighted average shares outstanding																	29,747	29,647		29,554
Add dilutive effect of stock options and restricted stock units (two-class method)																	10	10		12
Diluted average shares outstanding																	29,757	29,657		29,566
Basic income per share from continuing operations																	$ 3.07	$ 2.78		$ 2.24
Diluted income per share from continuing operations																	$ 3.07	$ 2.78		$ 2.24
Basic income (loss) per share from discontinued operations																	$ 0.00	$ 0.00		$ 0.00
Diluted income (loss) per share from discontinued operations																	$ 0.00	$ 0.00		$ 0.00

[1] (1) The fiscal year 2013 and 2012 data has been updated to reflect the reclassifications as disclosed in Note 1 - Company Overview and Basis of Presentation.