Consolidated Statements of Income - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020
Income Statement [Abstract]
Revenues	$ 424,725	$ 388,206
Operating expenses
Cost of services	207,149	188,088
Selling, general and administrative	94,915	79,087
Total operating expenses	302,064	267,175
Operating income	122,661	121,031
Other income (expense)
Interest expense, net	(1,494)	(1,029)
Other (expense) income, net	(1,237)	230
Income before income taxes	119,930	120,232
Provision for income taxes	12,283	19,026
Net income	$ 107,647	$ 101,206
Basic earnings per common share (in USD per share)	$ 2.86	$ 2.66
Diluted earnings per common share (in USD per share)	$ 2.79	$ 2.62
Basic weighted average common shares (in shares)	37,678	38,007
Diluted weighted average common shares (in shares)	38,641	38,697