Quarterly report pursuant to Section 13 or 15(d)

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

v3.4.0.3
Share-Based Compensation - Summary of Stock Options Outstanding under Plans (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended
Mar. 31, 2016
Dec. 31, 2015
Mar. 31, 2016
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]        
Number of Shares, Options outstanding at beginning of period     510,148  
Number of Shares, Options exercised     (22,209) (19,581)
Number of Shares, Options forfeited     (125)  
Number of Shares, Options expired     (3,375)  
Number of Shares, Options outstanding at end of period 484,439 510,148 484,439  
Number of Shares, Options exercisable at end of period 307,751   307,751  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]        
Weighted-Average Exercise Price Per Share, Options outstanding at beginning of period (in usd per share)     $ 24.38  
Weighted-Average Exercise Price Per Share, Options exercised (in usd per share)     15.35  
Weighted-Average Exercise Price Per Share, Options forfeited (in usd per share)     144.00  
Weighted-Average Exercise Price Per Share, Options expired (in usd per share)     168.04  
Weighted-Average Exercise Price Per Share, Options outstanding at end of period (in usd per share) $ 23.76 $ 24.38 23.76  
Weighted-Average Exercise Price Per Share, Options exercisable at end of period (in usd per share) $ 26.44   $ 26.44  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term [Abstract]        
Weighted-Average Remaining Contractual Life, Options outstanding at beginning of period 7 years 1 month 6 days 7 years 3 months 18 days    
Weighted-Average Remaining Contractual Life, Options exercised     6 years 10 months 24 days  
Weighted-Average Remaining Contractual Life, Options forfeited     1 month 6 days  
Weighted-Average Remaining Contractual Life, Options expired     8 months 12 days  
Weighted-Average Remaining Contractual Life, Options outstanding at end of period 7 years 1 month 6 days 7 years 3 months 18 days    
Weighted-Average Remaining Contractual Life, Options exercisable at end of period 6 years 8 months 12 days      
Aggregate Intrinsic Value of In-the-Money Options, Options outstanding at beginning of period     $ 3,219  
Aggregate Intrinsic Value of In-the-Money Options, Options outstanding at end of period $ 2,303 $ 3,219 2,303  
Aggregate Intrinsic Value of In-the-Money Options, Options exercisable at end of period $ 1,734   $ 1,734  
Intrinsic value represents the excess of the closing stock price related to options outstanding (in usd per share) $ 22.02 $ 23.72 $ 22.02