Net Income (Loss) Per Share - Summary of Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net loss	$ (6,697)	$ (24,511)	$ (25,297)	$ (30,494)
Weighted average shares outstanding	42,028	27,696	42,000	27,632
Effect of dilutive stock options (in shares)	0	0	0	0
Diluted shares outstanding (in shares)	42,028	27,696	42,000	27,632
Basic - net loss per share (in dollars per share)	$ (0.16)	$ (0.89)	$ (0.60)	$ (1.10)
Diluted - net loss per share (in dollars per share)	(0.16)	(0.89)	(0.60)	(1.10)
Cash dividends declared per share (in dollars per share)	$ 0.07	$ 0.07	$ 0.14	$ 0.14