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Stockholders' Equity - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Oct. 19, 2016
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
May 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Compensation expense       $ 3,200,000 $ 2,300,000  
Unrecognized compensation cost   $ 7,500,000   $ 7,500,000    
Weighted average remaining period       3 years    
Fair market value of the shares       $ 900,000    
Stock repurchase program, authorized amount           $ 50,000,000
Stock repurchase program, expiration period Dec. 31, 2019          
Repurchased shares of common stock       0    
Cash dividends declared (in USD per share)   $ 0.17 $ 0.15 $ 0.32 $ 0.30  
Maximum [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock repurchase program, authorized amount $ 30,000,000          
2004 Plan [Member] | Restricted Stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares subject to outstanding awards (in shares)   750,576   750,576    
2014 Plan [Member] | Restricted Stock [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares of common stock available for delivery pursuant to the grant of awards (in shares)   750,000   750,000    
Additional shares of common stock available for grant       750,000    
Restricted shares for vesting period       5 years