Revenues - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 8,320,159	$ 6,598,226	$ 17,035,802	$ 14,219,711
Energy
Disaggregation of Revenue [Line Items]
Revenues	1,372,158	1,461,050	2,630,005	3,356,473
Ag
Disaggregation of Revenue [Line Items]
Revenues	6,938,212	5,124,202	14,383,614	10,836,057
Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	9,789	12,974	22,183	27,181
ASC Topic 606
Disaggregation of Revenue [Line Items]
Revenues	2,417,018	2,448,031	4,832,941	5,506,045
ASC Topic 606 | Energy
Disaggregation of Revenue [Line Items]
Revenues	1,243,072	1,375,905	2,308,036	3,069,753
ASC Topic 606 | Ag
Disaggregation of Revenue [Line Items]
Revenues	1,169,411	1,066,783	2,513,910	2,425,409
ASC Topic 606 | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	4,535	5,343	10,995	10,883
ASC Topic 815
Disaggregation of Revenue [Line Items]
Revenues	5,882,419	4,120,592	12,162,541	8,638,254
ASC Topic 815 | Energy
Disaggregation of Revenue [Line Items]
Revenues	129,086	85,145	321,969	286,720
ASC Topic 815 | Ag
Disaggregation of Revenue [Line Items]
Revenues	5,753,333	4,035,447	11,840,572	8,351,534
ASC Topic 815 | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Guidance
Disaggregation of Revenue [Line Items]
Revenues	20,722	29,603	40,320	75,412
Other Guidance | Energy
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Guidance | Ag
Disaggregation of Revenue [Line Items]
Revenues	15,468	21,972	29,132	59,114
Other Guidance | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	$ 5,254	$ 7,631	$ 11,188	$ 16,298