Quarterly report pursuant to Section 13 or 15(d)

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

v3.10.0.1
Property and Equipment, Net of Accumulated Depreciation (Narrative) (Details)
$ in Millions
 1 Months Ended 3 Months Ended
Sep. 30, 2017
Aug. 31, 2018
USD ($)
Nov. 30, 2017
USD ($)
Aug. 31, 2017
USD ($)
ft²
item
May 31, 2018
USD ($)
Property, Plant and Equipment [Line Items]          
Depreciation expense   $ 29.4   $ 28.1  
Cost of building purchased   24.4   $ 18.0 [1]  
Multi-Building Campus [Member] | County Of Monroe Industrial Development Agency [Member]          
Property, Plant and Equipment [Line Items]          
Public benefits and inducements expiration date Dec. 31, 2039        
Multi-Building Campus [Member] | Rochester, NY [Member]          
Property, Plant and Equipment [Line Items]          
Number of buildings planned to be purchased | item       5  
Renovation square feet | ft²       300,000  
Cost of building purchased     $ 34.7    
Construction in progress   33.2     $ 32.0
Escrow for building renovations     $ 16.0    
Remaining balance in escrow   $ 4.4     $ 14.2
[1] Amounts have been adjusted to reflect the adoption of ASC Topic 606.