Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues	$ 57,460	$ 55,943
Cost and expenses
Cost of sales (exclusive of items shown separately below)	41,006	44,331
Asset retirement obligation accretion	128	123
Depreciation and amortization	4,116	2,438
Selling, general and administrative	3,960	3,431
Total cost and expenses	49,210	50,323
Operating income	8,250	5,620
Other income	298	489
Interest expense, net	(307)	(100)
Income before taxes	8,241	6,009
Income tax expense	1,358	743
Net income	$ 6,883	$ 5,266
Basic and diluted earnings per share
Basic (in dollars per share)	$ 0.17	$ 0.13
Diluted (in dollars per share)	$ 0.17	$ 0.13
Weighted average common shares outstanding
Basic (in shares)	40,604	39,905
Diluted (in shares)	40,652	40,142