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Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares issuable upon exercise of outstanding options 2,657,723 3,781,964 3,900,435 2,591,887
Number of shares to reduce shares available to grant by upon vesting of restricted stock units 594,305 598,892 760,183 1,998,224
Number of shares to reduce shares available to grant by upon vesting of deferred stock units 100,000      
Estimated pretax compensation expense $ 3.0      
Expiration period in years 4 years      
Service period in years 4 years      
Long-term incentive, cash-based awards 3 years      
Restricted stock awards settled in cash exercisable in percentage 25.00%      
Stock compensation and recognized liability $ 1.4 $ 4.8 $ 3.6  
Performance unit award expenses $ 2.1 $ 3.5 $ 1.1  
Volatility assumptions for estimating the fair value of stock options, minimum 65.30%      
Volatility assumptions for estimating the fair value of stock options, maximum 76.40%      
Chief Executive Officer [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Service period in years 2 years      
Restricted stock awards settled in cash exercisable in percentage 50.00%      
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%      
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%      
Long-term incentive, cash-based awards 4 years      
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 Shares [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 units   42,752 221,562 854,291
Restricted Stock Shares [Member] | Share-based Compensation Award, Tranche One [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Service period in years 4 years      
Restricted Stock Shares [Member] | Share-based Compensation Award, Tranche Two [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      
2008 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 1.67      
Common stock available for future share-based awards 6,600,000      
Shares issuable upon exercise of outstanding options 2,700,000