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Stockholders' Equity - Additional Information (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Feb. 13, 2017
Jul. 25, 2011
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Stockholders Equity [Line Items]                          
Common stock, value of shares authorized to repurchase   $ 200,000,000                      
Stock repurchase, shares   1,770,000                 44,798 369,133  
Value of shares repurchased   $ 52,000,000                 $ 1,545,000 $ 13,294,000 $ 20,809,000
Average price of repurchased shares                     $ 34.50 $ 36.01  
Cash dividends per common share     $ 0.17 $ 0.170 $ 0.170 $ 0.170 $ 0.170 $ 0.170 $ 0.170 $ 0.165 $ 0.680 $ 0.675 $ 0.655
Dividend payment to common shareholders       $ 36,361,000 $ 36,361,000 $ 36,361,000   $ 35,969,000 $ 35,969,000 $ 35,969,000 $ 36,361,000 $ 35,969,000 $ 34,851,000
Subsequent Event [Member]                          
Stockholders Equity [Line Items]                          
Dividend declared date Feb. 13, 2017                        
Cash dividend to be paid $ 0.175                        
Dividend to be paid date Mar. 10, 2017                        
Dividend declared, shareholders of record date Feb. 27, 2017