Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
Share-based Compensation - Summary of Stock Options Outstanding under Plans (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Options Outstanding, Number of Shares 387,901 510,148 603,872 546,595
Options Outstanding, Intrinsic Value $ 6,752      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 17.49 $ 24.38 $ 23.78 $ 28.09
Options Outstanding, Weighted-Average Remaining Contractual Life 6 years 9 months 18 days      
Options Exercisable, Number of Shares 341,561 333,460 224,766  
Options Exercisable, Intrinsic Value $ 6,054      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 16.85 $ 27.16 $ 33.35  
Options Exercisable, Weighted-Average Remaining Contractual Life 6 years 7 months 18 days      
Intrinsic value of stock options outstanding (in usd per share) $ 34.9      
$10.88 to $14.99 [Member]        
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      
Options Outstanding, Number of Shares 36,901      
Options Outstanding, Intrinsic Value $ 835      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 12.27      
Options Outstanding, Weighted-Average Remaining Contractual Life 5 years 5 months 12 days      
Options Exercisable, Number of Shares 36,901      
Options Exercisable, Intrinsic Value $ 835      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 12.27      
Options Exercisable, Weighted-Average Remaining Contractual Life 5 years 4 months 24 days      
$15.00 to $19.99 [Member]        
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      
Options Outstanding, Number of Shares 265,000      
Options Outstanding, Intrinsic Value $ 4,861      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 16.55      
Options Outstanding, Weighted-Average Remaining Contractual Life 6 years 8 months 18 days      
Options Exercisable, Number of Shares 255,000      
Options Exercisable, Intrinsic Value $ 4,710      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 16.43      
Options Exercisable, Weighted-Average Remaining Contractual Life 6 years 8 months 18 days      
$20.00 to $24.83 [Member]        
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      
Options Outstanding, Number of Shares 86,000      
Options Outstanding, Intrinsic Value $ 1,056      
Options Outstanding, Weighted-Average Exercise Price Per Share (in usd per share) $ 22.62      
Options Outstanding, Weighted-Average Remaining Contractual Life 7 years 8 months 18 days      
Options Exercisable, Number of Shares 49,660      
Options Exercisable, Intrinsic Value $ 509      
Options Exercisable, Weighted-Average Exercise Price Per Share (in usd per share) $ 22.39      
Options Exercisable, Weighted-Average Remaining Contractual Life 7 years 6 months 18 days