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Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares issuable upon exercise of outstanding options 3,085,888 2,657,723 3,781,964 3,900,435
Number of shares to reduce shares available to grant by upon vesting of restricted stock units 1,712,204 757,871 [1] 598,892 760,183
Estimated pretax compensation expense $ 5.0      
Expiration period in years 4 years      
Service period in years 4 years      
Restricted stock units settled in cash exercisable in percentage 25.00%      
Stock compensation and recognized liability $ 5.6 $ 1.4 $ 4.8  
Long-term incentive, cash-based awards 3 years      
Performance unit award expenses $ 5.4 $ 2.1 $ 3.5  
Volatility assumptions for estimating the fair value of stock options, minimum 66.30%      
Volatility assumptions for estimating the fair value of stock options, maximum 76.80%      
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%      
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
Service period in years 4 years      
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 3 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      
Restricted Stock Shares [Member] | Share-based Compensation Award, Tranche Three [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Service period in years 3 years      
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 units 1,712,204 757,871 [1] 556,140 538,621
Restricted Stock Units [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 20.00%      
Restricted Stock Units [Member] | 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 50.00%      
Restricted Stock Units [Member] | 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 30.00%      
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 4,300,000      
Shares issuable upon exercise of outstanding options 200,000      
2008 Incentive Compensation Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares issuable upon exercise of outstanding options 2,900,000      
Number of shares to reduce shares available to grant by upon vesting of restricted stock units 1,700,000      
2008 Incentive Compensation Plan [Member] | Chief Executive Officer [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Service period in years 2 years      
Restricted stock units settled in cash exercisable in percentage 50.00%      
Maximum [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 100,000      
[1] The total granted awards during 2015 and total outstanding balance as of December 31, 2015 includes an adjustment of 163,566 restricted stock units. These units were previously recorded in the summary table of restricted stock units settled in cash due to the potential for cash settlement upon an involuntary, not for cause termination.