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, 2017	Dec. 31, 2016		Dec. 31, 2015
Successor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ (5,296)				$ 32,662
Less: Preferred stock dividends	0				0
Net loss attributable to common shareholders	$ (5,296)				$ 32,662
Weighted-average shares – basic	14,992				14,996
Effect of dilutive securities	0	[1]			67
Weighted-average shares – diluted	14,992				15,063
Predecessor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)			$ 1,054,602			$ (1,582,961)
Less: Preferred stock dividends			(5,972)	[2]		(22,789)	[2]	$ (22,789)
Net loss attributable to common shareholders			$ 1,048,630			$ (1,605,750)		$ (1,605,750)
Weighted-average shares – basic			88,013			73,639		73,639
Effect of dilutive securities			36,074			0	[1]
Weighted-average shares – diluted			124,087			73,639		73,639
Potentially dilutive securities with the effect of being anti-dilutive excluded from the calculation of diluted earnings per common share	100							30,200

[1] 2 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. For 2015, approximately 30.2 million potentially dilutive securities, including Predecessor Preferred Stock, stock options and RSUs had the effect of being anti-dilutive and were excluded from the calculation of diluted earnings per common share.

[2] Preferred stock dividends were excluded from diluted earnings per share for the year ended December 31, 2015, as the assumed conversion of the outstanding preferred stock would have been anti-dilutive.