Stockholders' Equity - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
Equity [Abstract]
Common stock issued during the period | shares	40.5
Price per share of common stock issued during the period | $ / shares	$ 53.23
Proceeds from issuance of common stock | $	$ 2,160