v3.26.1
Equity - Stock Options (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
May 31, 2026
May 31, 2025
May 31, 2024
Stock options, additional disclosures      
Weighted-average remaining term (in years) for options outstanding 7 years 6 years 1 month 6 days 6 years 4 months 24 days
Weighted-average remaining term (in years) for options exercisable 5 years 6 months 5 years 5 years 6 months
Employee Stock Option      
Assumptions used in the Black-Scholes option pricing models to estimate the fair value of each stock option grant      
Risk-free interest rate 3.90% 4.20% 4.10%
Expected volatility of common stock 34.10% 36.00% 42.30%
Dividend yield 0.00% 0.00% 0.00%
Expected option term in years 4 years 9 months 18 days 4 years 10 months 24 days 5 years 1 month 6 days
Shares      
Outstanding at beginning of year (in shares) 935,000 1,004,000 1,573,000
Granted (in shares) 160,085 157,310 141,545
Exercised (in shares) (474,000) (212,000) (706,000)
Cancelled (in shares) (27,000) (14,000) (5,000)
Outstanding at end of year (in shares) 594,000 935,000 1,004,000
Options exercisable at end of year (in shares) 318,000 635,000 696,000
Weighted Average Exercise Price      
Outstanding at beginning of year (in dollars per share) $ 44.94 $ 38.49 $ 33.24
Exercise price (in dollars per share) 80.17 67.02 58.27
Exercised (in dollars per share) 40.42 29.81 30.67
Cancelled (in dollars per share) 72.61 60.59 48.4
Outstanding at end of year (in dollars per share) 54.24 44.94 38.49
Options exercisable at end of year (in dollars per share) $ 39.94 $ 38.13 $ 33.95
Stock options, additional disclosures      
Total fair value of stock options vested $ 3.5 $ 2.9 $ 3.3
Total intrinsic value of stock options exercised 26.3 8.0 22.5
Aggregate intrinsic value of options outstanding 31.4 16.3  
Unearned compensation not yet recognized $ 4.1    
Average remaining expensed period of unearned compensation 1 year 9 months 18 days    
Employee Stock Option | Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpenses      
Stock options, additional disclosures      
Compensation expense $ 3.7 $ 3.5 $ 3.0