Equities - Narrative (Details) $ in Thousands	12 Months Ended
	Aug. 31, 2022 USD ($) pools	Aug. 31, 2021 USD ($)	Aug. 31, 2020 USD ($)
Class of Stock [Line Items]
Estimated patronage refunds	$ (500,000)	$ (50,000)	$ (30,000)
Cash patronage dividends payable	$ (51,026)	(30,042)	(90,115)
Patronage source earnings, percentage allocated to reserves	10.00%
Capital equity certificates, number of pools | pools	2
Equity redemptions, age	70 years
Redemptions of equities	$ 111,818	79,381	96,438
Preferred stock dividends paid	(168,668)	(168,668)	(168,668)
Estimated Cash Patronage Dividends Payable	500,000
futurePaymentsForRepurchaseOfOtherEquity	(500,000)
Total Patronage refunds, estimated	1,162,700
nonqualified patronage, estimated	153,900
Total patronage refunds	1,200,000
Class B, Series 1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Redemption Amount	536,500
Capital Reserves
Class of Stock [Line Items]
Estimated patronage refunds	(1,162,661)	(280,290)	(241,970)
Nonqualified Equity Certificates
Class of Stock [Line Items]
Estimated patronage refunds	153,858	$ 230,290	$ 211,970
Qualified Equity Certificates
Class of Stock [Line Items]
Estimated patronage refunds	508,800
Capital Equity Certificates
Class of Stock [Line Items]
Estimated patronage refunds	$ 508,803