Income Taxes (Schedule Of Effective income Tax Rate Reconciliation)(Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Income Taxes [Abstract]
U.S statutory rate	$ 22,788	$ 19,780	$ 12,874
State and local taxes, net of federal tax benefit	1,337	889	540
State tax credits			(1,393)
Foreign tax rate differences	(338)	(257)	(122)
Domestic production activities deduction	(1,900)	(1,301)	(608)
R&D, Phone, and Fuel tax credits	(105)	(239)	(28)
Other	49	840	657
Effective rate	$ 21,831	$ 19,712	$ 11,920
U.S statutory rate, percentage	35.00%	35.00%	35.00%
State and local taxes, net of federal tax benefit, percentage	2.00%	1.60%	1.50%
State tax credits, percentage			(3.80%)
Foreign tax rate differences, percentage	(0.50%)	(0.50%)	(0.30%)
Domestic production activities deduction, percentage	(2.90%)	(2.30%)	(1.70%)
R&D, Phone, and Fuel tax credits, percentage	(0.20%)	(0.40%)	(0.10%)
Other	0.10%	1.50%	1.80%
Effective rate, percentage	33.50%	34.90%	32.40%