Earnings per Share - Calculation of Earnings (Loss) per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Line Items]
Net income (loss)		$ (17,685)	$ (41,336)	$ (367,199)	$ 5,157	$ 18,641	$ (31,477)	$ (426,220)	$ (7,679)
Net (income) loss allocated to participating restricted stockholders		0			(128)			0	0
Basic and diluted earnings available to common stockholders		$ (17,685)			$ 5,029			$ (426,220)	$ (7,679)
Common shares/units:
Common shares outstanding — basic		37,626			33,707			37,596	26,093
Dilutive effect of potential common shares		0			0			0	0
Common shares outstanding — diluted		37,626			33,707			37,596	26,093
Net earnings per share:
Basic		$ (0.47)			$ 0.15			$ (11.34)	$ (0.29)
Diluted		$ (0.47)			$ 0.15			$ (11.34)	$ (0.29)
Stock Options [Member]
Net earnings per share:
Antidilutive stock options or warrants	[1]	0			3			0	3
Warrants [Member]
Net earnings per share:
Antidilutive stock options or warrants	[2]	2,174			9,154			2,174	9,154

[1] Amount represents options to purchase common stock that are excluded from the diluted net earnings per share calculations because of their antidilutive effect.

[2] Amount represents warrants to purchase common stock that are excluded from the diluted net earnings per share calculations because of their antidilutive effect.