Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Goodwill and Intangible Assets, Net of Accumulated Amortization (Components of Intangible Assets, at Cost) (Details) - USD ($)
$ in Millions
Feb. 28, 2018
May 31, 2017
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross $ 314.1 $ 298.9
Less: Accumulated amortization 209.0 241.3
Intangible assets, net of accumulated amortization 105.1 57.6
Client Lists [Member]    
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross [1] 308.4 293.5
Other Intangible Assets [Member]    
Finite-Lived Intangible Assets [Line Items]    
Total intangible assets, gross $ 5.7 $ 5.4
[1] Client lists include current estimates of amounts acquired from Lessor as of February 28, 2018. Refer to Note C for further details.