Variable Interest Entities - Schedule of variable interest entities, credit commitments (Details) - USD ($) $ in Thousands	May 31, 2026	May 31, 2025
Variable Interest Entity [Line Items]
CFC third-party guarantees	$ 1,265,694	$ 1,210,606
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Total CFC credit commitments	5,000,000	5,000,000
Borrowings payable to CFC	1,642,033	1,640,372
CFC third-party guarantees	105,346	60,564
Other credit enhancements	817	1,275
Total credit enhancements	106,163	61,839
Total outstanding commitments	1,748,196	1,702,211
CFC credit commitments available	$ 3,251,804	$ 3,297,789