Unaudited Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Unaudited Condensed Consolidated Statements of Operations
Revenue	$ 76,377	$ 39,459	$ 195,889	$ 117,769
Cost and expenses
Cost of sales (exclusive of items shown separately below)	54,808	35,689	143,768	96,758
Asset retirement obligations accretion	156	128	461	428
Depreciation and amortization	6,751	5,258	18,861	15,601
Selling, general and administrative	5,895	5,966	15,767	15,723
Total costs and expenses	67,610	47,041	178,857	128,510
Operating income (loss)	8,767	(7,582)	17,032	(10,741)
Other income	789	1,743	7,156	11,456
Interest expense, net	(933)	(344)	(1,418)	(915)
Income (loss) before tax	8,623	(6,183)	22,770	(200)
Income tax expense (benefit)	1,588	(1,407)	1,650	(38)
Net loss	$ 7,035	$ (4,776)	$ 21,120	$ (162)
Earnings (loss) per common share
Basic earnings (in dollars per share)	$ 0.16	$ (0.11)	$ 0.48	$ 0.00
Diluted earnings (in dollars per share)	$ 0.16	$ (0.11)	$ 0.48	$ 0.00
Weighted average common shares outstanding
Basic weighted average shares outstanding (in shares)	44,109	42,647	43,915	42,373
Diluted weighted average shares outstanding (in shares)	44,465	42,647	43,996	42,373