Quarterly report pursuant to Section 13 or 15(d)

Property and Equipment, Net of Accumulated Depreciation (Narrative) (Details)

v3.19.1
Property and Equipment, Net of Accumulated Depreciation (Narrative) (Details)
$ in Millions
 3 Months Ended 9 Months Ended
Feb. 28, 2019
USD ($)
ft²
Feb. 28, 2018
USD ($)
Nov. 30, 2017
USD ($)
item
Feb. 28, 2019
USD ($)
ft²
Feb. 28, 2018
USD ($)
May 31, 2018
USD ($)
Property, Plant and Equipment [Line Items]            
Depreciation expense $ 32.1 $ 31.5   $ 91.7 $ 88.0  
Cost of building purchased [1]       88.0 $ 122.0 [2]  
Multi-Building Campus [Member] | Rochester, NY [Member]            
Property, Plant and Equipment [Line Items]            
Number of buildings purchased | item     5      
Cost of building purchased     $ 34.7      
Escrow for building renovations     $ 16.0      
Remaining balance in escrow $ 0.0     $ 0.0   $ 14.2
Multi-Building Campus [Member] | Rochester, NY [Member] | Minimum [Member]            
Property, Plant and Equipment [Line Items]            
Renovation square feet | ft² 300,000     300,000    
[1] Amounts have been adjusted to reflect the adoption of Accounting Standards Update ("ASU") No. 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)."
[2] Amounts have been adjusted to reflect the adoption of ASC Topic 606.