Quarterly report [Sections 13 or 15(d)]

Funds Held for Clients and Corporate Investments (Narrative) (Details)

v3.25.2
Funds Held for Clients and Corporate Investments (Narrative) (Details)
$ in Millions
3 Months Ended 12 Months Ended
Aug. 31, 2025
USD ($)
Security
May 31, 2025
USD ($)
Security
Schedule of Available-for-sale Securities [Line Items]    
Net unrealized losses on available-for-sale securities $ (21.0) $ (53.6)
Number of available-for-sale securities in an unrealized loss position | Security 505 600
Percentage of available-for-sale securities in an unrealized loss position 45.00% 50.00%
Gross unrealized losses on available-for-sale securities $ 50.8 $ 68.0
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 5.0 7.0
Corporate Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Sep. 01, 2025  
Corporate Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Jan. 23, 2035  
Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 33.2 $ 44.3
Municipal Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Sep. 01, 2025  
Municipal Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Aug. 01, 2032  
Variable Rate Demand Notes [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities contractual maturities 20 years  
Variable Rate Demand Notes [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities contractual maturities 30 years