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Accounting for Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Jul. 31, 2022
Feb. 28, 2023
Aug. 31, 2022
Feb. 28, 2022
Feb. 28, 2023
Feb. 28, 2022
Stock options, additional disclosures            
Compensation expense         $ 8.5 $ 4.6
Assumptions used in the Black-Scholes option pricing models to estimate the fair value of each stock option grant            
Risk-free interest rate         3.10%  
Expected volatility of common stock         42.20%  
Dividend yield         0.00%  
Expected option term in years         5 years 2 months 12 days  
Restricted stock            
Stock options, additional disclosures            
Compensation expense   $ 2.6   $ 0.2 $ 7.5 2.9
Performance-based restricted stock            
Stock options, additional disclosures            
Granted (in shares)     74,660      
Stock appreciation units            
Stock options, additional disclosures            
Granted (in shares)     93,450      
Granted (in dollars per share)     $ 41.88      
Stock appreciation units | Board of Directors            
Stock options, additional disclosures            
Granted (in shares)     28,314      
Granted (in dollars per share)     $ 48.56      
Stock options            
Stock options, additional disclosures            
Granted (in shares) 221,900          
Exercise price (in dollars per share) $ 41.88          
Weighted average fair value of stock options granted (in dollars per share) $ 17.61          
Total intrinsic value of stock options exercised         8.6 4.3
Compensation expense   $ 0.9   $ 0.8 $ 2.9 $ 2.9