Segment Information - Items Not Allocated to Segments (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
General and administrative expense		$ (56,531)	$ (21,597)	$ (27,253)
Gain of sale of assets		113,411	166,747	1,585
Interest expense		(8,532)	(19,985)	(34,066)
Loss on extinguishment of debt, net		(611)	(35,864)	0
Other corporate non-operating income		3,600	1,718	3,006
Income (loss) before taxes from continuing operations		50,043	90,815	8,214
Items Not Allocated To Segments
Segment Reporting Information [Line Items]
General and administrative expense		(50,354)	(18,274)	(24,802)
Share-based and long-term incentive compensation expense		(7,201)	(4,425)	(4,474)
Gain of sale of assets		28,674	48,891	0
Interest expense		(8,532)	(19,985)	(34,066)
Loss on extinguishment of debt, net		(611)	(35,864)	0
Other corporate non-operating income		1,627	350	256
Income (loss) before taxes from continuing operations	[1]	$ (36,397)	$ (29,307)	$ (63,086)

[1] Items not allocated to segments consist of: For the Year 2017 2016 2015 (In thousands)General and administrative expense$(50,354) $(18,274) $(24,802)Share-based and long-term incentive compensation expense(7,201) (4,425) (4,474)Gain on sale of assets28,674 48,891 —Interest expense(8,532) (19,985) (34,066)Loss on extinguishment of debt, net(611) (35,864) —Other corporate non-operating income1,627 350 256 $(36,397) $(29,307) $(63,086)