Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 25,627	$ 20,236
Costs and expenses
Operating costs	18,926	14,898
Selling, general and administrative	3,479	3,718
Depreciation and amortization	6,591	6,256
Asset impairment, net	(35)	129
(Gain) loss on disposition of assets, net	(82)	828
Total costs and expenses	28,879	25,829
Operating loss	(3,252)	(5,593)
Interest expense	(943)	(630)
Loss before income taxes	(4,195)	(6,223)
Income tax (benefit) expense	(49)	46
Net loss	$ (4,146)	$ (6,269)
Loss per share:
Basic and diluted (usd per share)	$ (0.11)	$ (0.17)
Weighted average number of common shares outstanding:
Basic and diluted (shares)	38,124	37,546