XML 66 R50.htm IDEA: XBRL DOCUMENT v3.19.1
Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares issuable upon exercise of outstanding options 2,769,000   2,818,000
Estimated pretax compensation expense $ 10.0    
Expiration period in years 4 years    
Service period in years 4 years    
Restricted stock units settled in shares exercisable in percentage 25.00%    
Restricted stock units settled in cash exercisable in percentage 25.00%    
Stock compensation and recognized liability $ 1.0 $ 1.1  
Long-term incentive, cash-based awards 3 years    
Performance unit award expenses $ 0.6 $ 0.7  
Share-based Compensation Award, Tranche Two [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock awards settled in stock exercisable in percentage 33.33%    
Share-based Compensation Award, Tranche Three [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock awards settled in stock exercisable in percentage 33.33%    
Non-Employee Directors' Stock Options [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expiration period in years 10 years    
Employee stock options exercisable in percentage 100.00%    
Employee Stock Option [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expiration period in years 10 years    
Service period in years 4 years    
Employee Stock Option [Member] | Share-based Compensation Award, Tranche One [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock awards settled in stock exercisable in percentage 25.00%    
Restricted Stock Units [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Number of shares to reduce shares available to grant by upon vesting of restricted stock awards and units 1,535,000   2,017,000
Service period in years 4 years    
Performance-based Restricted Stock Units [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Service period in years 3 years    
Deferred Stock Units to be Settled in Shares [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Service period in years 3 years    
2016 Incentive Compensation Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock subject to awards of stock options or stock appreciation rights payable in shares 1.0    
Common stock subject to any other form of award 1.35    
Common stock available for future share-based awards 2,200,000    
Shares issuable upon exercise of outstanding options 800,000    
Number of shares to reduce shares available to grant by upon vesting of restricted stock awards and units 1,900,000    
2008 Incentive Compensation Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares issuable upon exercise of outstanding options 2,000,000    
Number of shares to reduce shares available to grant by upon vesting of restricted stock awards and units 200,000