CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 15,520	$ 21,639	$ 20,383
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of discount on available for sale debt securities	(58)	(54)	(51)
Amortization of deferred offering costs	207	478	199
Gain on sale of U.S. Treasury bonds-available for sale	(4)
Depreciation, depletion and amortization	47,172	30,517	21,993
Deferred tax benefit	(7)	(78)	(29)
Change in fair value of derivative financial instruments	281	(9,165)	(540)
Stock option expense	2,592	1,546	2,429
Change in assets and liabilities:
Increase in accounts receivable-trade	(4,157)	(879)	(1,121)
Decrease (increase) in other assets	(41)	71	(443)
Increase in accounts payable and accruals	6,618	3,646	3,221
Decrease in other long term liabilities	(1,286)	(965)	(720)
Net cash provided by operating activities	66,837	46,756	45,321
Cash flows from investing activities:
Purchase, exploration and development of oil and gas properties	(61,397)	(56,598)	(23,380)
Acquisition of oil and gas properties	(15,607)
Purchases of property and equipment	(2,666)	(7,578)	(5,702)
Proceeds from U.S. Treasury bonds-available for sale	13
Net cash used in investing activities	(79,657)	(64,176)	(29,082)
Cash flows from financing activities:
Proceeds from line of credit	20,000	98,657
Payments on debt and debentures	(10,158)	(81,838)	(21,462)
Proceeds from the exercise of stock options	839	123	128
Repurchase of preferred stock, net			(1,051)
Net cash provided by (used in) financing activities	10,681	16,942	(22,385)
Net decrease in cash and cash equivalents	(2,139)	(478)	(6,146)
Cash and cash equivalents at beginning of year	10,614	11,092	17,238
Cash and cash equivalents at end of year	8,475	10,614	11,092
Supplemental disclosure of cash flow information
Cash paid for interest	3,181	2,699	3,269
Noncash investing and financing activities:
Accrued preferred stock dividend	10	10	18
Change in accounts payable relating to oil and gas property	(15,750)	10,630	3,518
Note payable on purchase of property and equipment			3,500
Increase in asset retirement liability	$ 9,491	$ 5,260	$ 1,428