Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets, Net of Accumulated Amortization (Components of Intangible Assets, at Cost) (Details)

v3.5.0.2
Goodwill and Intangible Assets, Net of Accumulated Amortization (Components of Intangible Assets, at Cost) (Details) - USD ($)
$ in Millions
May 31, 2016
May 31, 2015
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross $ 294.6 $ 247.8
Less: Accumulated amortization 225.1 215.4
Intangible assets, net of accumulated amortization 69.5 32.4
Client Lists [Member]    
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross 289.2 244.6
Other Intangible Assets [Member]    
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross $ 5.4 $ 3.2