Quarterly report [Sections 13 or 15(d)]

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

v3.26.3
Funds Held for Clients and Corporate Investments (Narrative) (Details)
$ in Millions
3 Months Ended 12 Months Ended
Aug. 31, 2026
USD ($)
Security
May 31, 2026
USD ($)
Security
Schedule of Available-for-sale Securities [Line Items]    
Net unrealized losses on available-for-sale securities $ 92.4 $ 52.5
Number of available-for-sale securities in an unrealized loss position | Security 821 664
Percentage of available-for-sale securities in an unrealized loss position 77.00% 60.00%
Gross unrealized losses on available-for-sale securities $ 94.2 $ 59.8
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 43.6 18.8
Corporate Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Sep. 01, 2026  
Corporate Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Apr. 17, 2036  
Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 20.0 $ 21.1
Municipal Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Sep. 01, 2026  
Municipal Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date May 01, 2033  
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