Revenue (Effect of New Revenue Guidance, Impact on Income Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenue	$ 25,282,320
Cost of revenue	23,368,919	$ 20,388,624	$ 17,517,478
Operating income	701,356	542,153	410,230
Income tax expense	161,230	285,860	129,066
Net income	289,474	$ 87,541	$ 127,167
Balance without the adoption of ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenue	24,864,754
Cost of revenue	23,057,603
Operating income	595,105
Income tax expense	164,054
Net income	$ 180,399