Supplemental Cash Flow and Other Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Jul. 31, 2017	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Net cash paid during the period for:
Interest		$ 160,040	$ 147,089	$ 130,571
Income taxes		14,571	5,184	54,229
Transfer of Financial Assets Accounted for As Sales, Deferred Purchase Price Receivable, Transfer of Notes Receivables		747,345	0	0
Debt Extinguished During Sale of Financial Assets	$ 554,000	554,000	0	0
Deferred Purchase Price Recognized for Transfer of Financial Assets Accounted for as Sales		547,553	0	0
Fair Value of Assets Acquired		138,699	0	0
Capital Expenditures and Major Repairs Incurred but Not yet Paid		22,490	44,307	60,226
Capital Lease Obligations Incurred		6,832	23,921	9,741
Other significant noncash investing and financing transactions:
Capital equity certificates redeemed with preferred stock		19,985	76,756	0
Capital equity certificates issued in exchange for Ag Business acquisitions		2,928	19,089	15,618
Dividends and equities payable		$ 12,121	$ 198,031	$ 384,427