Fair Value Measurement - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Nov. 30, 2021	May 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	$ 37,505	$ 35,102
Debt securities trading, at fair value	588,615	576,175
Deferred compensation investments	7,595	7,222
Derivative assets	78,610	121,259
Derivative liabilities	615,097	584,989
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	37,505	35,102
Debt securities trading, at fair value	0	0
Deferred compensation investments	7,595	7,222
Derivative assets	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Debt securities trading, at fair value	588,615	576,175
Deferred compensation investments	0	0
Derivative assets	78,610	121,259
Derivative liabilities	615,097	584,989
Recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	37,505	35,102
Debt securities trading, at fair value	588,615	576,175
Deferred compensation investments	7,595	7,222
Derivative assets	78,610	121,259
Derivative liabilities	615,097	584,989
Recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	37,505	35,102
Debt securities trading, at fair value	0	0
Deferred compensation investments	7,595	7,222
Derivative assets	0	0
Derivative liabilities	0	0
Recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Debt securities trading, at fair value	588,615	576,175
Deferred compensation investments	0	0
Derivative assets	78,610	121,259
Derivative liabilities	$ 615,097	$ 584,989