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Subsequent Event - Additional Information (Detail) - $ / shares
Jul. 10, 2019
Jul. 10, 2018
Jul. 11, 2017
Subsequent Event [Line Items]      
Annual common stock dividend declared   $ 2.55 $ 2.50
Dividend payable date, declared day   Jul. 10, 2018 Jul. 11, 2017
Dividend payable date   Aug. 17, 2018 Aug. 15, 2017
Stockholders of record date   Aug. 03, 2018 Aug. 02, 2017
Subsequent Event [Member]      
Subsequent Event [Line Items]      
Special cash dividend $ 2.40    
Annual common stock dividend declared $ 0.60    
Dividend payable date, declared day Jul. 10, 2019    
Dividend payable date Aug. 20, 2019    
Stockholders of record date Aug. 06, 2019