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SHARE-BASED COMPENSATION - Stock Units and Director Stock Grants (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation $ 12.3 $ 7.9 $ 7.3
Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation 7.9 7.1 7.2
Stock and Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Intrinsic value of units vested $ 4.8 $ 3.0 $ 4.9
No. of Stock Units      
Beginning of year (in shares) 854    
Granted (in shares) 370    
Vested and settled (in shares) (291)    
Cancelled (in shares) (77)    
End of year (in shares) 856 854  
Weighted Average Fair Value      
Beginning of year (in USD per share) $ 21.42    
Granted (in USD per share) 18.09 $ 13.64 $ 34.23
Vested and settled (in USD per share) 24.76    
Cancelled (in USD per share) 21.37    
Stock and stock units, end of year (in USD per share) $ 18.79 $ 21.42