Earnings Per Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Options to purchase shares of common stock not included in the computation of diluted earnings per share	100,000	2,200,000	500,000	700,000
Repurchased shares of common stock	0		4,200,000
Average price per share			$ 98.50
Total cash outlay			$ 415.5