Earnings Per Share - Calculation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
BASIC EPS:
Net loss attributed to common stockholders	$ (75,042)	$ (33,769)	$ (120,172)	$ (189,492)
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	218,059	211,875	219,635	191,237
Basic net loss per common share	$ (0.34)	$ (0.16)	$ (0.55)	$ (0.99)
DILUTED EPS:
Net loss attributed to common stockholders	$ (75,042)	$ (33,769)	$ (120,172)	$ (189,492)
Weighted average number of common shares outstanding, excluding non-vested shares of restricted stock	218,059	211,875	219,635	191,237
Weighted average number of diluted common shares outstanding	218,059	211,875	219,635	191,237
Diluted net loss per common share	$ (0.34)	$ (0.16)	$ (0.55)	$ (0.99)
Potentially dilutive securities excluded as anti-dilutive	9,052	9,973	9,052	9,973