Derivative Instruments and Hedging Activities - Schedule of derivatives offsetting (Details) - USD ($) $ in Thousands	May 31, 2026	May 31, 2025
Derivative [Line Items]
Derivative asset, fair value, amount not offset against collateral	$ 554,116	$ 555,855
Derivative liability, fair value, amount not offset against collateral	31,414	51,368
Interest rate swaps
Derivative [Line Items]
Derivative asset, fair value, gross asset	554,116	555,855
Derivative asset, fair value, gross liability	0	0
Derivative asset, fair value, amount not offset against collateral	554,116	555,855
Derivative, collateral, obligation to return securities	30,572	49,806
Derivative, collateral, obligation to return cash	0	0
Derivative asset, fair value, amount offset against collateral	523,544	506,049
Derivative liability, fair value, gross liability	31,414	51,368
Derivative liability, fair value, gross asset	0	0
Derivative liability, fair value, amount not offset against collateral	31,414	51,368
Derivative, collateral, right to reclaim securities	30,572	49,806
Derivative, collateral, right to reclaim cash	0	0
Derivative liability, fair value, amount offset against collateral	$ 842	$ 1,562