Earnings (Loss) Per Share - Schedule of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss (numerator):
Net loss	$ (63,307)	$ (26,801)	$ (73,011)	$ (40,687)	$ (813,869)	$ (81,468)	$ (41,970)	$ (34,103)	$ (203,806)	$ (971,410)	$ (183,176)
Weighted-average shares (denominator):
Weighted-average number of shares of common stock—basic and diluted									241,434	217,897	144,369
Loss per share:
Basic and diluted	$ (0.23)	$ (0.10)	$ (0.33)	$ (0.18)	$ (3.66)	$ (0.37)	$ (0.19)	$ (0.17)	$ (0.84)	$ (4.46)	$ (1.27)