v3.26.1
Income Taxes - Effective tax rate reconciliation after ASU 2023-09 (Details) - USD ($)
$ in Millions
12 Months Ended
May 31, 2026
May 31, 2025
May 31, 2024
Amount      
U.S. federal statutory income tax rate $ 17.9    
State and local income tax, net of federal income tax benefit 6.6    
Research and development tax credit (1.2)    
Foreign tax credit (1.2)    
Changes in unrecognized tax benefits 1.4    
Effect of cross-border tax laws 0.0    
Charitable contributions (0.9)    
Global intangible low-taxed income 2.8    
FDII (2.8)    
Equity and other compensation (1.0)    
Section 162(m) limitation 2.1    
Other federal tax adjustments (1.0)    
Other nontaxable or nondeductible items 1.0    
 Total Current and Deferred $ 28.5 $ 0.6 $ 4.1
Percent      
U.S. federal statutory income tax rate 21.00% 21.00% 21.00%
State and local income tax, net of federal income tax benefit 7.80% (66.50%) (3.00%)
Other, net   (0.20%) 0.10%
Foreign tax rate differential   (61.40%) (0.10%)
Research and development tax credit (1.40%)    
Foreign tax credit (1.40%)    
Changes in unrecognized tax benefits 1.60% 40.70% 0.40%
Effect of cross-border tax laws 0.00%    
GILTI inclusion 3.30% 0.00% 0.10%
Foreign derived intangible income deduction (3.30%)    
Charitable contributions (1.10%)    
Equity and other compensation (1.10%)    
Section 162(m) limitation 2.50% (83.50%) 6.00%
Other federal tax adjustments (1.10%)    
Other nontaxable or nondeductible items 0.90% 29.00% 1.30%
Effective tax rates 33.40% (46.20%) 25.30%
Tax Jurisdiction of Domicile [Extensible Enumeration] United States    
Australia      
Amount      
Permanent differences (1.50%)    
Other $ (0.7)    
Sale of equity method investment 4.1    
Percent      
Permanent differences $ (1.3)    
Other, net (0.80%)    
Sale of equity method investment 4.80%    
Canada      
Amount      
Other $ 1.0    
Foreign tax rate differential $ 1.0    
Percent      
Other, net 1.20%    
Foreign tax rate differential 1.20%    
Other foreign jurisdictions      
Amount      
Foreign tax rate differential $ 1.8    
Percent      
Foreign tax rate differential 2.10%    
United States      
Amount      
Sale of equity method investment $ (1.1)    
Percent      
Sale of equity method investment (1.30%)