Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Summary of Stock Options Outstanding under Plans (Detail)

v3.10.0.1
Share-based Compensation - Summary of Stock Options Outstanding under Plans (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
$10.80 to $14.99        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Exercise Price Range, Lower Limit (in usd per share) $ 10.88      
Exercise Price Range, Upper Limit (in usd per share) 14.99      
$15.00 to $19.99        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Exercise Price Range, Lower Limit (in usd per share) 15.00      
Exercise Price Range, Upper Limit (in usd per share) 19.99      
$20.00 to $24.83        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Exercise Price Range, Lower Limit (in usd per share) 20.00      
Exercise Price Range, Upper Limit (in usd per share) $ 24.83      
2007 and 2013 Plan        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Options Outstanding, Number of Shares (shares) 338,338 364,088 387,901 510,148
Options Outstanding, Intrinsic Value $ 924      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 17.52 $ 17.86 $ 17.49 $ 24.38
Options Exercisable, Number of Shares (shares) 338,338 354,753 341,561  
Options Exercisable, Intrinsic Value $ 924      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 17.52 $ 17.71 $ 16.85  
Intrinsic value of stock options outstanding (in usd per share) $ 19.70      
2007 and 2013 Plan | $10.80 to $14.99        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Options Outstanding, Number of Shares (shares) 12,338      
Options Outstanding, Intrinsic Value $ 90      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 12.36      
Options Outstanding, Weighted-Average Remaining Contractual Life 3 years 7 months      
Options Exercisable, Number of Shares (shares) 12,338      
Options Exercisable, Intrinsic Value $ 90      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 12.36      
Options Exercisable, Weighted-Average Remaining Contractual Life 3 years 7 months      
2007 and 2013 Plan | $15.00 to $19.99        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Options Outstanding, Number of Shares (shares) 265,000      
Options Outstanding, Intrinsic Value $ 834      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 16.55      
Options Outstanding, Weighted-Average Remaining Contractual Life 4 years 8 months      
Options Exercisable, Number of Shares (shares) 265,000      
Options Exercisable, Intrinsic Value $ 834      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 16.55      
Options Exercisable, Weighted-Average Remaining Contractual Life 4 years 8 months      
2007 and 2013 Plan | $20.00 to $24.83        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Options Outstanding, Number of Shares (shares) 61,000      
Options Outstanding, Intrinsic Value $ 0      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 22.73      
Options Outstanding, Weighted-Average Remaining Contractual Life 5 years 10 months      
Options Exercisable, Number of Shares (shares) 61,000      
Options Exercisable, Intrinsic Value $ 0      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 22.73      
Options Exercisable, Weighted-Average Remaining Contractual Life 5 years 10 months