Derivative Instruments and Hedging Activities - Schedule of derivative instruments on consolidated balance sheets (Details) - USD ($) $ in Thousands	May 31, 2026	May 31, 2025
Derivative assets:
Derivative assets, fair value	$ 554,116	$ 555,855
Derivative assets, notional amount	5,550,124	5,694,835
Derivative liabilities:
Derivative liabilities, fair value	31,414	51,368
Derivative liabilities, notional amount	1,015,409	1,557,400
Interest rate swaps
Derivative assets:
Derivative assets, fair value	554,116	555,855
Derivative assets, notional amount	5,550,124	5,694,835
Derivative liabilities:
Derivative liabilities, fair value	31,414	51,368
Derivative liabilities, notional amount	1,015,409	$ 1,557,400
Forward pay-fixed swaps
Derivative assets:
Derivative assets, notional amount	$ 21,000