Quarterly report pursuant to Section 13 or 15(d)

Business Combinations (Narrative) (Details)

v3.8.0.1
Business Combinations (Narrative) (Details)
$ in Millions
9 Months Ended
Feb. 28, 2018
USD ($)
Aug. 18, 2017
USD ($)
state
Feb. 28, 2018
USD ($)
Business Acquisition [Line Items]      
Goodwill acquired     $ 170.3
Lessor Group [Member]      
Business Acquisition [Line Items]      
Effective acquisition date     Feb. 28, 2018
Purchase price $ 160.6    
Goodwill acquired $ 119.2    
HR Outsourcing, 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 acquired   $ 51.1  
HR Outsourcing, Inc. [Member] | Minimum [Member]      
Business Acquisition [Line Items]      
Number of states in which HR Solutions services are provided | state   35