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Stockholders' Equity - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Equity [Abstract]    
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement 50,000,000  
Stock repurchased, shares 900,000  
Shares repurchased, average price per share $ 20.27  
Additional shares authorized for purchase 3,600,000  
Number of Options, exercised 358,000  
Exercise price of stock options, lower range limit $ 15.29  
Exercise price of stock options, upper range limit $ 23.64  
Proceeds from stock option exercises $ 6,606 $ 1,076