Earnings Per Share - Calculation of Basic Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basic earnings (loss) per share:
Net income (loss) available to common stockholders	$ 18,215	$ 12,505
Basic weighted-average shares of common stock outstanding	283,399	273,780
Basic earnings (loss) per share	$ 0.06	$ 0.05