Quarterly report pursuant to Section 13 or 15(d)

Service Revenue (Narrative) (Details)

v3.19.3
Service Revenue (Narrative) (Details) - USD ($)
$ in Millions
 3 Months Ended
Aug. 31, 2019
Aug. 31, 2018
Service Revenue [Line Items]    
Contracts term 30 days  
Direct pass-through costs for payroll wages and payroll taxes $ 5,100.0 $ 2,200.0
Direct pass-through costs related to state unemployment insurance 14.7 8.8
Direct pass-through costs related to guaranteed cost benefit plans $ 165.8 74.7
Revenue performance obligations timing the Company defers revenue associated with these performance obligations, which exceed one year, and subsequently recognizes these as future services are provided, over approximately three years to four years  
Capitalized contract cost, amortization period 8 years  
Impairment loss $ 0.0 $ 0.0
Minimum [Member]    
Service Revenue [Line Items]    
Revenue performance obligations timing, years 3 years  
Maximum [Member]    
Service Revenue [Line Items]    
Revenue performance obligations timing, years 4 years