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Stockholders' Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended
Jul. 31, 2017
Jun. 30, 2017
Mar. 31, 2017
Jun. 30, 2016
Mar. 31, 2016
Jun. 30, 2017
Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Dividend declared and paid per share   $ 0.19 $ 0.19 $ 0.18 $ 0.18    
Aggregate dividend declared for the year           $ 6,800,000 $ 6,400,000
Dividend declared per share   $ 0.19   $ 0.18   $ 0.38 $ 0.36
Authorized to purchase of common stock under the stock repurchase program   $ 485,000,000       $ 485,000,000  
Repurchase of common Stock   400,000       1,000,000 0
Cumulative aggregate cost of repurchase of common stock   $ 15,000,000       $ 36,500,000  
Cumulative repurchase of common stock   16,000,000       16,000,000  
Aggregate cost of repurchase of common stock           $ 461,400,000  
Subsequent Event [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Dividend declared per share $ 0.19            
Dividend payable, date declared Sep. 20, 2017            
Dividend payable, record date Sep. 06, 2017