Quarterly report pursuant to Section 13 or 15(d)

Description of Business, Basis of Presentation, and Significant Accounting Policies (Narrative) (Details)

v3.24.3
Description of Business, Basis of Presentation, and Significant Accounting Policies (Narrative) (Details)
$ in Millions
3 Months Ended 12 Months Ended
Aug. 31, 2024
USD ($)
Item
Segment
Aug. 31, 2023
USD ($)
Item
May 31, 2025
USD ($)
May 31, 2024
USD ($)
Item
Accounting Policies [Line Items]        
Number of reportable segments | Segment 1      
Revision increased net cash provided by investing activities $ 37.2      
Allowance for credit losses 25.0     $ 21.3
Advance collections 1.7     0.7
Maximum individual health insurance claims liability       0.5
Stock-based compensation costs recognized $ 16.5 $ 16.0    
Change in accounting principle, accounting standards update, adopted [true false] false      
Forecast [Member]        
Accounting Policies [Line Items]        
Maximum individual health insurance claims liability     $ 0.5  
Trade Receivables [Member]        
Accounting Policies [Line Items]        
Receivables $ 162.5     141.3
Purchased Receivables [Member]        
Accounting Policies [Line Items]        
Receivables $ 988.7     $ 939.6
Accounts And Unbilled Receivables [Member]        
Accounting Policies [Line Items]        
Number of clients creating a credit concentration | Item 0     0
Revenue [Member]        
Accounting Policies [Line Items]        
Number of clients creating a credit concentration | Item 0 0    
PEO Aggregate Claims Exceeding $1.0M [Member] | Minimum [Member]        
Accounting Policies [Line Items]        
Individual workers' compensation claims liability       $ 1.0
PEO Aggregate Claims Exceeding $1.0M [Member] | Minimum [Member] | Forecast [Member]        
Accounting Policies [Line Items]        
Individual workers' compensation claims liability     1.0  
PEO Aggregate Claims Exceeding $1.0M [Member] | Maximum [Member]        
Accounting Policies [Line Items]        
Maximum individual workers' compensation claims liability       $ 1.0
PEO Aggregate Claims Exceeding $1.0M [Member] | Maximum [Member] | Forecast [Member]        
Accounting Policies [Line Items]        
Maximum individual workers' compensation claims liability     $ 1.0