Components of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	4 Months Ended		8 Months Ended	12 Months Ended
	Dec. 31, 2016		Sep. 12, 2016	Dec. 31, 2018	Dec. 31, 2017
Successor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ (5,296)			$ 224,785	$ 32,662
Less: Preferred stock dividends	0			0	0
Net loss attributable to common shareholders	$ (5,296)			$ 224,785	$ 32,662
Weighted-average shares – basic	14,992			15,059	14,996
Effect of dilutive securities	0	[1]		233	67
Weighted-average shares – diluted	14,992			15,292	15,063
Predecessor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)			$ 1,054,602
Less: Preferred stock dividends			(5,972)
Net loss attributable to common shareholders			$ 1,048,630
Weighted-average shares – basic			88,013
Effect of dilutive securities			36,074
Weighted-average shares – diluted			124,087
Potentially dilutive securities with the effect of being anti-dilutive excluded from the calculation of diluted earnings per common share	100

[1] For the period from September 13, 2016 through December 31, 2016, less than 0.1 million potentially dilutive securities, represented by RSUs, had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per common share.