Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Revenues	$ 196,448	$ 173,289
Operating expenses
Cost of services	66,833	56,785
Selling, general and administrative	62,862	57,075
Total operating expenses	129,695	113,860
Operating income	66,753	59,429
Other income	277	125
Income before income taxes	67,030	59,554
Provision for income taxes	21,486	17,953
Net income	$ 45,544	$ 41,601
Basic earnings per common share (in Dollars per share)	$ 1.01	$ 0.90
Diluted earnings per common share (in Dollars per share)	$ 0.99	$ 0.88
Weighted average common shares (Basic) (in Shares)	45,107	46,283
Weighted average common shares (Diluted) (in Shares)	46,103	47,487