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Stockholders' Equity - Additional Information (Details) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Aug. 25, 2017
Jul. 31, 2017
Sep. 30, 2017
Sep. 30, 2017
Sep. 30, 2016
Feb. 25, 2016
Equity [Abstract]            
Common stock dividends paid   $ 59,400,000   $ 178,200,000 $ 156,700,000  
Dividends paid per common share (in dollars per share) $ 0.63          
Stock repurchase program, authorized amount           $ 200,000,000
Number of shares of common stock repurchased     0 0