Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 10,224	$ 45,073	$ 70,099	$ 158,310
Costs and expenses
Operating costs	8,663	34,246	52,987	111,032
Selling, general and administrative	2,796	3,755	10,101	11,308
Severance and merger-related expenses	0	320	1,076	2,688
Depreciation and amortization	10,767	11,154	33,338	33,838
Asset impairment	0	1,966	16,619	9,839
(Gain) loss on disposition of assets, net	(326)	265	(1,208)	3,503
Other expense	0	122	0	377
Total costs and expenses	21,900	51,828	112,913	172,585
Operating loss	(11,676)	(6,755)	(42,814)	(14,275)
Interest expense	(3,554)	(3,560)	(10,812)	(10,913)
Loss before income taxes	(15,230)	(10,315)	(53,626)	(25,188)
Income tax (benefit) expense	(31)	232	(84)	590
Net loss	$ (15,199)	$ (10,547)	$ (53,542)	$ (25,778)
Loss per share:
Basic and diluted (in dollars per share)	$ (2.67)	$ (2.80)	$ (11.91)	$ (6.82)
Weighted average number of common shares outstanding:
Basic and diluted (in shares)	5,703	3,770	4,495	3,780