Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Aug. 31, 2025	Aug. 31, 2024	Aug. 31, 2023
Income Statement [Abstract]
Revenues	$ 2,321,748	$ 2,203,056	$ 2,085,508
Operating expenses
Cost of services	1,097,782	1,011,945	973,225
Selling, general and administrative	475,663	489,812	483,076
Total operating expenses	1,573,445	1,501,757	1,456,301
Operating income	748,303	701,299	629,207
Other income (expense), net
Interest income	6,533	14,447	12,809
Interest expense	(56,324)	(65,778)	(66,319)
Other income (expense), net	22,446	1,535	8,257
Total other income (expense), net	(27,345)	(49,796)	(45,253)
Income before income taxes	720,958	651,503	583,954
Provision for income taxes	123,918	114,377	115,781
Net income	$ 597,040	$ 537,126	$ 468,173
Basic earnings per common share (in USD per share)	$ 15.74	$ 14.11	$ 12.26
Diluted earnings per common share (in USD per share)	$ 15.55	$ 13.91	$ 12.04
Basic weighted average common shares (in shares)	37,924	38,059	38,194
Diluted weighted average common shares (in shares)	38,385	38,618	38,898