Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating Activities
Net income	$ 8,461	$ 11,720
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in gain of joint venture	0	(2,034)
Change in derivative fair value	(6,840)	(10,472)
Monetization of derivative contracts	0	12,364
Depreciation, depletion, and amortization	12,285	10,218
Impairment	1,977	1,306
Amortization of deferred financing fees	(676)	(296)
Accretion of future site restoration	335	235
Stock-based compensation	1,142	1,199
Changes in operating assets and liabilities:
Accounts receivable	(6,474)	1,507
Other	4,941	(79)
Accounts payable and accrued expenses	6,268	(517)
Net cash provided by operating activities	22,771	25,743
Investing Activities
Capital expenditures, including purchases and development of properties	(33,466)	(35,116)
Proceeds from sale of oil and gas properties	3,192	0
Net cash used in investing activities	(30,274)	(35,116)
Financing Activities
Proceeds from long-term borrowings	21,000	14,500
Payments on long-term borrowings	(13,101)	(4,089)
Deferred financing fees	(96)	(603)
Exercise of stock options	44	0
Other	(29)	(128)
Net cash provided by financing activities	7,818	9,680
Effect of exchange rate changes on cash	56	1
Increase in cash	371	308
Cash and equivalents, at beginning of period	2,061	0
Cash and equivalents, at end of period	2,432	308
Supplemental disclosure of cash flow information:
Interest paid	$ 2,256	$ 2,289