Consolidated Statements of Income - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2022	May 31, 2021
Income Statement [Abstract]
Revenues	$ 488,751	$ 399,558	$ 1,344,595	$ 1,179,551
Operating expenses
Cost of services	222,618	205,257	629,162	588,868
Selling, general and administrative	119,881	76,599	309,185	235,818
Long-lived asset impairments	48,998	0	62,985	0
Total operating expenses	391,497	281,856	1,001,332	824,686
Operating income	97,254	117,702	343,263	354,865
Other income (expense), net
Interest expense, net	(12,051)	(1,839)	(15,218)	(4,682)
Other income (expense), net	77	(1,587)	(879)	(1,009)
Income before income taxes	85,280	114,276	327,166	349,174
Provision for income taxes	10,370	13,597	34,671	50,646
Net income	$ 74,910	$ 100,679	$ 292,495	$ 298,528
Basic earnings per common share (in USD per share)	$ 1.97	$ 2.66	$ 7.76	$ 7.87
Diluted earnings per common share (in USD per share)	$ 1.93	$ 2.62	$ 7.58	$ 7.73
Basic weighted average common shares (in shares)	37,934	37,806	37,716	37,910
Diluted weighted average common shares (in shares)	38,720	38,488	38,607	38,602