Annual report pursuant to Section 13 and 15(d)

Income Taxes (Reconciliation of U.S. Federal Statutory Tax Rate) (Details)

v3.23.2
Income Taxes (Reconciliation of U.S. Federal Statutory Tax Rate) (Details)
12 Months Ended
May 31, 2023
May 31, 2022
May 31, 2021
Income Tax Disclosure [Abstract]      
Federal statutory tax rate 21.00% 21.00% 21.00%
Increase/(decrease) resulting from:      
State income taxes, net of federal tax benefit 4.20% 4.60% 4.30%
Tax-exempt municipal bond interest (0.20%) (0.20%) (0.30%)
Stock option windfall benefit (0.40%) (0.90%) (1.20%)
Tax credits (0.70%) (1.10%) (0.60%)
Other items 0.10% 0.30% 0.30%
Effective income tax rate 24.00% 23.70% 23.50%