Annual report pursuant to Section 13 and 15(d)

STOCK-BASED COMPENSATION - Total Stock-Based Compensation Expense (Details)

v3.10.0.1
STOCK-BASED COMPENSATION - Total Stock-Based Compensation Expense (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Stock-based compensation expense, before income taxes $ 42.5 $ 38.3 $ 37.1
Cost of services      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Stock-based compensation expense, before income taxes 9.5 7.2 4.5
Selling, general and administrative expenses      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Stock-based compensation expense, before income taxes $ 33.0 $ 31.1 $ 32.6