Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Activities
Net income	$ 4,704	$ 595
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in derivative fair value	613	592
Depreciation, depletion, and amortization	7,635	6,509
Amortization of deferred financing fees	348	333
Accretion of future site restoration	144	172
Stock-based compensation	439	474
Changes in operating assets and liabilities:
Accounts receivable	6,812	(8,804)
Other	113	(69)
Accounts payable and accrued expenses	(18,384)	10,111
Net cash provided by operating activities	2,424	9,913
Investing Activities
Capital expenditures, including purchases and development of properties	(36,719)	(17,773)
Proceeds from sale of oil and gas properties	2,782	0
Net cash used in investing activities	(33,937)	(17,773)
Financing Activities
Proceeds from long-term borrowings	27,000	12,000
Payments on long-term borrowings	(370)	(6,047)
Exercise of stock options	46	0
Other	(20)	0
Net cash provided by financing activities	26,656	5,953
Effect of exchange rate changes on cash	1	0
Decrease in cash	(4,856)	(1,907)
Cash and equivalents, at beginning of period	5,205	2,061
Cash and equivalents, at end of period	349	154
Supplemental disclosure of cash flow information:
Interest paid	$ 430	$ 1,016