CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 30,385	$ 15,520	$ 21,639
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of discount on available for sale debt securities	(61)	(58)	(54)
Amortization of deferred offering costs	218	207	478
Gain on sale of U.S. Treasury bonds-available for sale		(4)
Depreciation, depletion and amortization	44,806	47,172	30,517
Deferred tax expense (benefit)	64	(7)	(78)
Change in fair value of derivative financial instruments	2,523	281	(9,165)
Stock option expense	2,062	2,592	1,546
Change in assets and liabilities:
Increase in accounts receivable-trade	(3,890)	(4,157)	(879)
Decrease (increase) in other assets	(764)	(41)	71
Increase in accounts payable and accruals	5,856	6,618	3,646
Decrease in other long term liabilities	(1,846)	(1,286)	(965)
Net cash provided by operating activities	79,353	66,837	46,756
Cash flows from investing activities:
Purchase, exploration and development of oil and gas properties	(69,162)	(61,397)	(56,598)
Acquisition of oil and gas properties		(15,607)
Purchases of property and equipment	(2,680)	(2,666)	(7,578)
Proceeds from U.S. Treasury bonds-available for sale		13
Net cash used in investing activities	(71,842)	(79,657)	(64,176)
Cash flows from financing activities:
Proceeds from line of credit	5,000	20,000	98,657
Payments on debt and debentures	(10,077)	(10,158)	(81,838)
Proceeds from the exercise of stock options	711	839	123
Net cash provided by (used in) financing activities	(4,366)	10,681	16,942
Net increase (decrease) in cash and cash equivalents	3,145	(2,139)	(478)
Cash and cash equivalents at beginning of year	8,475	10,614	11,092
Cash and cash equivalents at end of year	11,620	8,475	10,614
Supplemental disclosure of cash flow information
Cash paid for interest	2,672	3,181	2,699
Noncash investing and financing activities:
Accrued preferred stock dividend	10	10	10
Change in accounts payable relating to oil and gas property	4,029	(15,750)	10,630
Increase in asset retirement liability	$ 1,139	$ 9,491	$ 5,260