Revenues - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2018	Nov. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 8,484,289	$ 8,031,884
Energy
Disaggregation of Revenue [Line Items]
Revenues	2,161,288
Ag
Disaggregation of Revenue [Line Items]
Revenues	6,305,397
Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	17,604
ASC 606
Disaggregation of Revenue [Line Items]
Revenues	3,301,250
ASC 606 | Energy
Disaggregation of Revenue [Line Items]
Revenues	1,940,190
ASC 606 | Ag
Disaggregation of Revenue [Line Items]
Revenues	1,355,826
ASC 606 | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	5,234
ASC 815
Disaggregation of Revenue [Line Items]
Revenues	5,134,526
ASC 815 | Energy
Disaggregation of Revenue [Line Items]
Revenues	221,098
ASC 815 | Ag
Disaggregation of Revenue [Line Items]
Revenues	4,913,428
ASC 815 | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	0
Other Guidance
Disaggregation of Revenue [Line Items]
Revenues	48,513
Other Guidance | Energy
Disaggregation of Revenue [Line Items]
Revenues	0
Other Guidance | Ag
Disaggregation of Revenue [Line Items]
Revenues	36,143
Other Guidance | Corporate and Other
Disaggregation of Revenue [Line Items]
Revenues	$ 12,370