Variable Interest Entities - Information on CFCs Credit Commitments to NCSC and RTFC (Details) - USD ($) $ in Thousands	Aug. 31, 2023	May 31, 2023
Variable Interest Entity [Line Items]
CFC third-party guarantees	$ 900,441	$ 796,821
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Total CFC credit commitments	5,500,000	5,500,000
Borrowings payable to CFC	1,442,215	1,428,886
CFC third-party guarantees	16,679	15,263
Other credit enhancements	1,274	2,038
Total credit enhancements	17,953	17,301
Total outstanding commitments	1,460,168	1,446,187
CFC credit commitments available	$ 4,039,832	$ 4,053,813