Quarterly report pursuant to Section 13 or 15(d)

Business Combinations (Narrative) (Details)

v3.10.0.1
Business Combinations (Narrative) (Details)
$ in Millions
6 Months Ended
Dec. 20, 2018
USD ($)
Feb. 28, 2018
USD ($)
Aug. 18, 2017
USD ($)
state
Nov. 30, 2018
USD ($)
Nov. 23, 2018
state
item
May 31, 2018
USD ($)
[1]
Business Acquisition [Line Items]            
Goodwill       $ 810.6   $ 814.0
Oasis Outsourcing Group Holdings, L.P. [Member]            
Business Acquisition [Line Items]            
Acquisition agreement date       Nov. 23, 2018    
Effective acquisition date       Dec. 20, 2018    
Number of states | state         50  
Oasis Outsourcing Group Holdings, L.P. [Member] | Subsequent Event [Member]            
Business Acquisition [Line Items]            
Purchase price $ 1,000.0          
Cash on hand portion of purchase price 400.0          
Credit facility portion of purchase price 800.0          
Cash acquired $ 200.0          
Oasis Outsourcing Group Holdings, L.P. [Member] | Minimum [Member]            
Business Acquisition [Line Items]            
Number of clients | item         8,400  
Lessor Group [Member]            
Business Acquisition [Line Items]            
Effective acquisition date       Feb. 28, 2018    
Purchase price   $ 162.5        
Cash acquired   13.4        
Goodwill   $ 111.5        
HR Outsourcing Holdings, Inc. [Member]            
Business Acquisition [Line Items]            
Effective acquisition date       Aug. 18, 2017    
Purchase price     $ 75.4      
Cash portion of purchase price     42.2      
Common stock issued portion of purchase price     33.2      
Goodwill     $ 51.1      
HR Outsourcing Holdings, Inc. [Member] | Minimum [Member]            
Business Acquisition [Line Items]            
Number of states | state     35      
[1] Amounts have been adjusted to reflect the adoption of ASC Topic 606.