STOCK BASED COMPENSATION - Stock-Based Compensation Expense Resulting from Stock Option Awards, RSUs, PSUs and ESPP (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4.3	$ 7.1
Stock Options | Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	2.0	3.0
Restricted Stock Units (RSUs) | Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1.8	2.1
Performance-Based Restricted Stock Units | Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	0.2	1.6
ESPP | Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 0.3	$ 0.4