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Stockholders' Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Oct. 31, 2018
May 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Sep. 30, 2018
Sep. 30, 2017
Feb. 28, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Common stock, par value     $ 0.01           $ 0.01     $ 0.01
Dividend declared and paid per share     0.20 $ 0.20 $ 0.20 $ 0.19 $ 0.19 $ 0.19        
Aggregate dividend declared for the year                 $ 10,800,000 $ 10,200,000    
Dividend declared per share     $ 0.20     $ 0.19     $ 0.60 $ 0.57    
Authorized to purchase of common stock under the stock repurchase program     $ 535,000,000           $ 535,000,000   $ 50,000,000  
Repurchase of common Stock           100,000     200,000 1,100,000    
Cumulative aggregate cost of repurchase of common stock     $ 300,000     $ 3,500,000     $ 10,000,000 $ 40,000,000    
Cumulative repurchase of common stock     16,300,000           16,300,000      
Aggregate cost of repurchase of common stock                 $ 474,900,000      
Subsequent Event [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Dividend declared per share $ 0.20                      
Dividend payable, date declared 2018-10                      
Dividend declared payable date Dec. 26, 2018                      
Dividend payable, record date Dec. 12, 2018                      
Employee Stock Purchase Plan [Member]                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Number of additional shares to be granted   400,000                    
Common stock, par value   $ 0.01