Variable Interest Entities - Consolidated Assets and Liabilities of VIEs included in CFCs Condensed Consolidated Financial Statements (Details) - USD ($) $ in Thousands	Aug. 31, 2023	May 31, 2023	Aug. 31, 2022
Assets:
Other assets	$ 72,139	$ 64,723
Total assets	34,694,163	34,012,060	$ 32,082,294
Liabilities:
Total liabilities	31,946,236	31,422,811
Variable interest entity, primary beneficiary
Assets:
Loans outstanding	1,462,423	1,444,662
Other assets	8,017	12,612
Total assets	1,470,440	1,457,274
Liabilities:
Total liabilities	$ 19,118	$ 19,704