Quarterly report [Sections 13 or 15(d)]

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

v3.26.1
Funds Held for Clients and Corporate Investments (Narrative) (Details)
$ in Millions
9 Months Ended 12 Months Ended
Feb. 28, 2026
USD ($)
Security
May 31, 2025
USD ($)
Security
Schedule of Available-for-sale Securities [Line Items]    
Net unrealized losses on available-for-sale securities $ 7.2 $ (53.6)
Number of available-for-sale securities in an unrealized loss position | Security 415 600
Percentage of available-for-sale securities in an unrealized loss position 37.00% 50.00%
Gross unrealized losses on available-for-sale securities $ 31.4 $ 68.0
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 3.1 7.0
Corporate Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Mar. 01, 2026  
Corporate Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Nov. 20, 2035  
Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 20.7 $ 44.3
Municipal Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Mar. 01, 2026  
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