Equity - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 31, 2021	May 31, 2021	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2021	Nov. 30, 2020	Aug. 31, 2021	Aug. 31, 2020	May 31, 2020
Stockholder's Equity [Line Items]
Equity increase (decrease)					$ (9,000)
Equity		$ 1,399,879	$ 1,390,985	$ 891,719	1,390,985	$ 891,719	$ 1,254,220	$ 731,504	$ 648,822
Patronage capital retirement			2,414	0	59,979	59,857
Net income			135,729	160,521	45,397	305,108
Cash Flow Hedging
Stockholder's Equity [Line Items]
Expected reclassification from AOCI over 12 months					1,000
Patronage Capital Allocated
Stockholder's Equity [Line Items]
Equity		923,970	866,405	834,209	866,405	834,209	866,405	834,209	894,066
Patronage capital retirement					57,565	59,857
Members’ Capital Reserve
Stockholder's Equity [Line Items]
Equity		909,749	909,749	807,320	909,749	807,320	909,749	807,320	807,320
Membership Fees and Educational Fund
Stockholder's Equity [Line Items]
Equity		3,125	$ 2,665	$ 2,551	$ 2,665	$ 2,551	$ 2,756	$ 2,939	$ 3,193
Net income		$ 1,000
Parent Company | Patronage Capital Allocated
Stockholder's Equity [Line Items]
Patronage capital retirement	$ 58,000
Net income allocations	$ 90,000
Percentage of patronage capital allocation	50.00%
Parent Company | Members’ Capital Reserve
Stockholder's Equity [Line Items]
Patronage capital retirement	$ 102,000
Parent Company | Retained earnings allocation of 50% of prior year patronage capital allocation
Stockholder's Equity [Line Items]
Patronage capital retirement	45,000
Parent Company | Retained earnings allocation held for twenty five years
Stockholder's Equity [Line Items]
Patronage capital retirement	$ 13,000
Period for which prior years allocated patronage capital is required to be held	25 years