Loss per Share - Schedule of Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Basic loss per share, Net Loss	$ (37,020)	$ (62,844)
Diluted loss per share, Net Loss	$ (37,020)	$ (62,844)
Basic loss per share, Shares	83,354	86,209
Diluted loss per share, Shares	83,354	86,209
Basic loss per share, Per Share Amount	$ (0.44)	$ (0.73)
Diluted loss per share, Per Share Amount	$ (0.44)	$ (0.73)