Annual report pursuant to Section 13 and 15(d)

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

v3.22.2
Funds Held for Clients and Corporate Investments (Narrative) (Details)
$ in Millions
12 Months Ended
May 31, 2022
USD ($)
Security
May 31, 2021
USD ($)
Security
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 139.0 $ 4.0
Net unrealized gain (loss) on available-for-sale securities $ (136.3) $ 79.3
Number of available-for-sale securities in an unrealized loss position | Security 817 137
Percentage of available-for-sale securities in an unrealized loss position 64.00% 11.00%
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 19.0 $ 0.2
Corporate Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Jun. 09, 2022  
Corporate Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Dec. 13, 2028  
Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross unrealized losses on available-for-sale securities $ 92.5 $ 2.3
Municipal Bonds [Member] | Minimum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Jun. 01, 2022  
Municipal Bonds [Member] | Maximum [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities maturity date Apr. 01, 2029  
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