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Shareholders' Equity - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Sep. 30, 1999
Stockholders Equity Note [Line Items]        
Preferred stock outstanding 0 0    
Number of shares authorized to be repurchased       7,500,000
Treasury stock, shares repurchased 0 0 0  
Cost of repurchased shares $ 114,425 $ 114,425    
Remaining number of shares authorized to be repurchased 1,129,087      
Common Stock        
Stockholders Equity Note [Line Items]        
Amount of votes common stock is entitled One      
Percentage of Board entitled to elect 25.00%      
Treasury stock, shares 6,322,650 6,322,650    
Class B Common Stock        
Stockholders Equity Note [Line Items]        
Amount of votes common stock is entitled Ten      
Treasury stock, shares 48,263 48,263